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ENGINEERING WORKS SPECIFICATION
Typical Civil and Structural Engineering Specification for Sewerage Works
PED/SDQS/SPEC-CWS/SPEC/0808(017)
PREFACE Indah Water Konsortium Sdn. Bhd. (IWK) is the national sewerage services company responsible to plan, design, operate and manage the national sewerage infrastructure in Peninsular Malaysia. Since its inception in 1994, IWK had seen through the steep improvements in the country’s lagging standards in the sewerage sector. Series of procedures, guidelines, standards, specifications and best practices had been developed and introduced over the past decade to enhance the standards in the sewerage industry. This has resulted in a better planned and well organised development of new sewerage systems to fulfil the whole life infrastructure obligations. This continual effort is important in moving the industry to higher standards which will uplift the image of our local sewerage industry. This document contains the key ‘Engineering Specification’ deliberately catering to the needs of Civil and Structural works of sewerage facilities. It sets out the typical requirements of engineering works detail aiming to minimise variation of works quality whilst enhancing the functionality of end product in the construction of sewage treatment plant, pump station, sewer network etc. It is applicable to both new and refurbishment projects. The ‘Typical Civil and Structural Engineering Specification for Sewerage Works’ is presented in twelve (12) sections as follows: Section 1.0 Section 2.0 Section 3.0 Section 4.0 Section 5.0 Section 6.0 Section 7.0 Section 8.0 Section 9.0 Section 10.0 Section 11.0 Section 12.0
: General : Earthworks : Concrete : Formwork : Steel Reinforcement : Piling : Structural Steelwork : Sewers, Force Mains, Pipelaying, Manholes and Appurtenances : Building Works : Roadworks : Drainage Works : Miscellaneous
In the preparation of this document, references have been made to various internationally accepted codes of practice and standard, adapting them to local conditions. Considerable assistance and valuable advice have also been derived from panel of experts and such assistance is hereby acknowledged. Whilst complying with this specification is strongly encouraged, engineering discretion and best advice need to be sought for betterment in case to case application. It is IWK’s hope and vision to see a better and sustainable sewerage infrastructure in the coming years.
Prepared by Planning and Engineering Department Indah Water Konsortium Sdn. Bhd. October 2008
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ACKNOWLEDGEMENT This document was a cooperative effort between IWK Planning & Engineering Department (PED), IWK Capital Works & Refurbishment (CWRD), IWK Operation & Maintenance Department (OMD), and SMHB Sdn. Bhd. To all, Planning and Engineering Department (PED) would like to express recognition and appreciation to the following members in developing this document.
Ir. Abdul Rashid Abdul Rahman – IWK OMD Ir. Mohd Adnan Md Dom – IWK PED Ir. Moghan Muniandy – SMHB Sdn. Bhd. Ir. Mohd Taufik Salleh – IWK PED Ir. Tan Kok Hong – IWK CWRD Ir. Teh Teik Ho – IWK OMD Ir. Yam Soong Yeong – IWK CWRD Jama’iatul-Lailah bt Mohd. Jais – IWK PED Khor Bee Chin – IWK PED Ng Mee Weng – SMHB Sdn. Bhd. Stephanie Sim Lee Gaik – IWK PED Zakaria Mohd Yassin– SMHB Sdn. Bhd.
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© Copyright Indah Water Konsortium Sdn Bhd, 2008
All rights reserved. This publication is protected by copyright.
No part of this publication may be reproduced, distributed, transmitted, stored in a retrieval system, or reduced to any electronic medium without the written authority of the company.
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Table of Contents
TYPICAL CIVIL AND STRUCTURAL ENGINEERING SPECIFICATION FOR SEWERAGE WORKS Section 1
General
Section 2
Earthworks
Section 3
Concrete
Section 4
Formwork
Section 5
Steel Reinforcement
Section 6
Piling
Section 7
Structural Steelwork
Section 8
Sewers, Force Mains, Pipelaying, Manholes and Appurtenances
Section 9
Building Works
Section 10 Roadworks Section 11 Drainage Works Section 12 Miscellaneous
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Section 1 - General
1.0
GENERAL ....................................................................................................1-1 1.1
Materials ...........................................................................................1-1
1.2
Standards .........................................................................................1-1
1.3
Samples and Tests ..........................................................................1-1
1.4
Test Certificates...............................................................................1-2
1.5
Independent and Local Tests .........................................................1-2
1.6
Testing Facilities..............................................................................1-3
1.7
As-Built Survey ................................................................................1-3
1.8
Programme of Work.........................................................................1-4
1.9
Access Roads ..................................................................................1-6
1.10
Environmental and Social Protection Requirements....................1-7
1.11
Health, Safety and Environmental ................................................1-11
1.12
The Site...........................................................................................1-18
1.13
Access to the Site ..........................................................................1-18
1.14
Working Space and Work through Private Land.........................1-18
1.15
Trespass on Adjacent Property ....................................................1-19
1.16
Existing Services ...........................................................................1-19
1.17
Works in Roads and Footpaths ....................................................1-19
1.18
Claims for Damage to Person or Property...................................1-20
1.19
Amenities to be Preserved............................................................1-20
1.20
Works to be Kept Clear of Water ..................................................1-20
1.21
Discharge of Water and Waste .....................................................1-21
1.22
Temporary Fencing........................................................................1-21
1.23
Temporary Works Construction and Design ...............................1-21
1.24
Water Supply..................................................................................1-22
1.25
Power Supply .................................................................................1-22
1.26
Temporary Sanitary Conveniences ..............................................1-23
1.27
Site to be Kept Tidy .......................................................................1-23
1.28
General Hygiene and Medical Examination of Contractor's Employees.......................................................................................1-23
1.29
Temporary Buildings for Use by Contractor ...............................1-23
1.30
Temporary Offices for the S.O. and His Staff ..............................1-24
1.31
Transport for S.O. and His Staff ...................................................1-24
APPENDIX 1.1:
Standard Compliance
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1.0 General 1.1
Materials
The term 'materials' shall mean all materials and articles of every kind whether raw, processed or manufactured to be supplied by the Contractor for incorporation in the Works. Except as may be otherwise specified for particular parts of the Works, the provisions in this section of the Specification shall apply to materials and workmanship for any part of the Works. All materials other than natural or pretreated materials shall be new and of the kinds and qualities described in the Contract and shall at least be equal to approved samples. As soon as practicable after receiving the order to commence the Works, the Contractor shall inform the S.O. of the names of the suppliers from whom he proposes to obtain any materials, but he shall not place any order, without the approval of the S.O. which may be withheld until samples have been submitted and satisfactorily tested. The Contractor shall thereafter keep the S.O. informed of orders for and delivery dates of all materials. Materials shall be transported, handled and stored in such a manner as to prevent deterioration, damage or contamination.
1.2
Standards
All workmanship, materials and components throughout shall where applicable and unless otherwise stated in the Contract comply either (a) with the relevant Malaysian or British Standard or Code of Practice current on the date fixed for receipt of tenders or (b) with other Standards or Codes of Practice proposed by the Contractor at the time of submitting his tender provided that these Standards or Codes of Practice are equivalent or superior to the relevant Malaysian. Appendix 1.1 provides a list of standard compliance tabulating the relevant standards that need to be complied with for the design and execution of specified civil works. The acceptance of a tender based upon a Standard or Code proposed by the Contractor shall only signify the S.O.’s general approval to the use of such Standards or Codes and shall not make the S.O. liable to accept a Standard or Code subsequently found to be inferior to the corresponding Standard or Code. Where the relevant standard provides for the furnishing of a certificate to the S.O. stating that the materials supplied comply with all aspects with the standard, the Contractor shall obtain the certificate and forward it to the S.O.
1.3
Samples and Tests
The Contractor shall submit samples of such materials as may be required by the S.O. and shall carry out the specified tests directed by the S.O. at the place of manufacture or on the Site or at a laboratory approved by the S.O. Samples shall be submitted and tests carried out sufficiently early to enable further samples to be submitted and tested if required by the S.O. The Contractor shall prepare the necessary test pieces and
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supply all labour, appliances, testing apparatus and everything necessary for the carrying out of all the specified tests. Unless otherwise provided for separately in the Bill of Quantities, the cost of the samples and of conducting all the specified tests on the samples shall be included in the Contract Rates. The Contractor shall give the S.O. fourteen days notice in writing of the date on which any of the samples will be ready for testing or inspection at the place of manufacture or at a laboratory approved by the S.O. and unless the S.O. shall attend at the appointed place within the said fourteen days the test may proceed in his absence. Provided that the Contractor shall in any case submit to the S.O. within seven days of every test such number of certified copies (not exceeding six) of the test readings as the S.O. may require. Approval by the S.O. as to the placing of orders for materials or as to samples or tests shall not prejudice any of the S.O.’s powers under the Contract.
1.4
Test Certificates
Certificates shall be provided by the Contractor in respect of materials to be used in the Works giving the results of the specified tests. The required copies of submission shall be as per project specific requirement (refer General Specification of Tender Document). The material shall be suitably marked to enable it to be identified from references on the certificates. No materials subject to test shall be incorporated into the Works until the receipt by the S.O. of a satisfactory Test Certificate. In case of any items of the Works which have not been inspected at the manufacturer's works, the Contractor shall obtain from the manufacturer and supply to the S.O. certificates signed by the manufacturer giving the results of the tests as carried out and certifying that the items have been manufactured in accordance with this Specification.
1.5
Independent and Local Tests
The S.O. reserves the right to carry out any independent or local tests he may deem fit on any material to be used in the Works, at any stage of manufacture or delivery. Any samples of materials which may be required for such tests shall be provided by the Contractor at no extra cost to the Employer. The cost of making any such independent tests shall be borne by the Employer, unless it can be shown that the workmanship or materials under test are not in accordance with the Specification in which case the costs of the tests shall be borne by the Contractor. Any materials or completed items of the Works which are shown by such independent tests to be not in accordance with the Specification shall be rejected notwithstanding any previous certificate which may have been provided.
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1.6
Testing Facilities
The Contractor shall at his own expense arrange with the suppliers or manufacturers to supply the necessary gauges and prepare all test pieces and supply all labour and apparatus for testing which may be necessary or which may be required by the S.O for carrying out the tests and requirements of this Specifications at the Contractor’s premises or at the place of manufacture, and shall also provide all test pieces required. If the Contractor fails to perform any of the foregoing obligations, the S.O. shall be at liberty to perform the said obligations or any of them which the Contractor has failed to perform, either at the Contractor’s premises, places of manufacture or elsewhere and charge the costs and expenses thereof to the Contractor.
1.7
As-Built Survey
As-built survey shall cover the Works as completed, incorporating all modifications carried out during manufacture or after testing at or after testing at the Contractor’s and Manufacturer’s works and all modifications carried out in the course of the erection, testing and commissioning of the Plant and the construction of the civil works. These drawings may be produced by modifying drawings produced for manufacture and/or construction, or may be produced separately. Each item of the Plant, e.g., pumps, valves, motors, starters, cables, etc, shall be shown on detailed general arrangement drawings clearly marking the position of the component parts. All parts shall be numbered and the numbers given shall correspond to the numbers in the instruction manuals, spare parts lists, pamphlets and descriptive matter. Comprehensive electrical circuit drawings shall be provided showing the relation of one electrical item of equipment to another. In addition, each item of electrical equipment shall be provided with a schematic drawing and a wiring drawing. The schematic drawing shall show the connections in a schematic form enabling the operation to be ascertained, while the wiring drawing shall show the individual components approximately in their relative physical positions, with the electrical connections shown exactly as wired, to enable a particular component or connection to be located on the actual equipment. Every connection shall be numbered and the number given for a particular connection shall be the same on the schematic drawing, on the wiring drawing, and as tagged on the actual equipment itself. The draft record drawings shall be submitted to the S.O. before commissioning of the Works. The required copies for submission shall be as per project specific requirement (refer General Specification of Tender Document). The approved Record Drawings shall be bound in albums of A1 size to the approval of the S.O. The Contractor shall supply to the S.O., within three months of the issue of the Certificate of Practical Completion, a minimum of four (4) complete sets of the approved Record Drawings. One set of these drawings shall be on tracing linen and remaining three shall be paper prints, all of which shall be suitably bound with an appropriately titled cover. In addition, a further three (3).nos. complete sets of the above drawings to A3 size shall also be provided suitably bound with hard covers. One copy of each of the record drawings shall also be provided on CD-ROM. The submission of approved Record Drawings shall be as per project specific requirement.
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1.8
Programme of Work
The Contractor shall submit the Works Programme for the execution of the Works in a format and media to the approval of the S.O. The required copies of submission shall be as per project specific requirement. The Programme shall be in three levels of detail as follows: 1.
The Overall Programme which shows the major work items of the Works. Milestones and major interface dates as set out in the Programme of Works in the Schedule of Particulars shall be indicated on the overall programme. The Overall Programme shall be submitted to the S.O. for approval within fourteen (14) days of the award of the Contract.
2.
The six (6) months Working Programme which indicates further breakdown of the major work items of the Works into sub-items involved in each major item of work.
3.
The Detailed Working Programme which shows further breakdown of the sub-items into activities involved in the sub-items.
The Contractor shall use Critical Path Analysis (CPA) to analyse and identify critical activities and dates and shall present the programme in bar chart form and network diagram indicating activities and dates critical to completion of the Works on time. The Contractor shall produce all programmes from one (1) software database so that the programmes are inter-linked and fully co-ordinated. The programme shall show increasing detail, each succeeding programme level sub-dividing activities in the preceding level. The Contractor shall submit an explanatory report covering any aspect of the chart or network that the Contractor cannot show on the Chart. The Contractor shall develop the programme using a project management software to be approved by the S.O. The Contractor shall agree with the S.O. the work sections, activities, sub-activities, interface and other critical dates the Contractor is to identify in the Programmes. Upon approval of the S.O., the proposed overall programme shall become the Overall Works Programme based on which the Contractor shall complete the Works on time. This Overall Works Programme shall not be changed unless approved by the S.O. The Overall Works Programme shall show every significant activity required for the completion of the Contract including: 1.
Dates when construction drawings are required to be issued by the S.O.
2.
Construction of individual sections of the Works, differentiating between different function and trade activities.
3.
Submission of samples, designs, drawings and documents for items to be designed by or supplied by the Contractor.
4.
Approvals required from statutory authorities and agencies
5.
Testing of sections of the Works (e.g. hydraulic testing of pipelines and leakage testing of water retaining structures) Mobilisation, time on site and removal of major items of Contractor’s Plant and temporary facilities
6.
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7.
Dates when civil structures are specified to be available to commence plant installation
8.
Off-site activities such as prefabrication of components
9.
Plant and equipment installation, testing and commissioning
10.
Maintenance, operation and training
Each of the activity in the Overall Works Programme shall have the following information: 1.
Activity code, description, duration and the sequence with other activities
2.
The earlier and latest start and finish dates with available float
3.
The party responsible for each activity
4.
The cost weightage for each activity with respect to the total cost of all the activities in the Programme. The total weightage of all activities must add up to 1.
5.
The installation quantities and forecast manhour requirements.
The six months Working Programme shall contain the sub-items which are breakdowns of the major work items by area or zones, such that no activity shall have a duration exceeding 30 days. The detailed Working Programme shall indicate the major activities involved in the sub-items, e.g. formwork, reinforcement and casting and curing of concrete. The Programme shall identify the main quantities of materials and other agreed relevant information. The Contractor shall provide a concise master network diagram. The Contractor shall analyse the CPM network using the precedence diagram method. The work breakdown structure will be the same as that for the Overall Works Programme, and each major activity shall relate to the price breakdown headings. The activities presented in the programme shall be capable of indicating the required information similar to that required for the Overall Works Programme. The Contractor shall provide the S.O. with the six (6) months Working Programme and Weekly Detailed Working Programme. The Contractor shall immediately report to the S.O. details of all critical activities in delay and any delays the Contractor can foresee to future critical activities. If necessary the Contractor shall consult the S.O. and submit a revised programme for his approval and shall report the likely effect of these delays on the programme and the remedial action the Contractor proposes to rectify the delay such as, but not limited to: 1. 2. 3.
increasing resources increasing the hours worked carrying out activities in parallel
The approval by the S.O. of any revised programme shall not be deemed to be consent to any amendments of the completion dates or relieve the Contractor of his obligations under the Contract. Within twenty-eight (28) days of the Commencement Date, the Contractor and the S.O. shall agree to a schedule for weekly progress meetings covering the first six (6) months of the Works. The
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Contractor shall make himself available for any other meetings called for by the S.O. outside the schedule. The Contractor shall prepare the following programmes with increasing detail to demonstrate the Contractor’s shorter term and detailed planning of the execution of the activities: 1. 2.
Six (6) Months Working Programme Weekly Detailed Working Programme
The Six (6) Months Working Programme shall be submitted to the S.C. for approval monthly to cover the period for the next six (6) month’s planned work. The hard copy of the programme must also include the previous one (1) month’s progress. The electronic copy of the programme must also include progress for the period from the beginning of the Contract. The Weekly Detailed Working Programme shall be submitted to the S.O. for approval weekly and must show at least the previous week’s progress and the future two (2) week’s planned work. The Contractor shall issue relevant short-term programmes with method statements required in the Contractor project Quality Assurance Plan. To accurately reflect the status of the Works, the Contractor’s shall monitor, update, revise the programmes, and submit them to the S.O. in the monthly or weekly progress meetings or at such other times as instructed by the S.O. All the programmes submitted to the S.O. shall be in the electronic format using a project management software to be approved by the S.O. Upon approval by the S.O., the programmes shall become the current Working and Detailed Working Programmes. In addition, the Contractor shall develop within 30 days of award of the Contract, S-curves for cumulative financial and physical progress for the Works. These curves shall be up-dated monthly to show actual progress versus planned progress including a schedule of outstanding commitment figures. The Contractor shall provide explanations if the actual and planned progress differ significantly.
1.9
Access Roads
The access roads to and within the Site shall be completed for the readiness of the civil works as shown in the programme of work to permit plant erection and for easy access to the Employer and to others. For this purpose, the access roads shall be completed up to the binder coarse which will permit good and reasonable access at all times to complete the various sections of works as specified. The works to be completed shall also include all culverts, drains, manholes and all turfing necessary to prevent erosion and deposition of silt on the roads. The Contractor shall maintain and make good any damage of the roads for easy access to the Site and to areas within the Site. It is intended that the final top wearing course shall be laid towards the later part of the Contract period after the main construction and erection activities have been completed. Before laying the top wearing course, the road surfaces shall be cleaned and all damaged portions including the road base and sub-base shall be made good to the satisfaction of the S.O. The Contractor shall maintain and make good any damaged areas to the satisfaction of the S.O. until all construction and erection works are completed notwithstanding whether the damages of the access roads are due to the Contractor’s own doing or by others.
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1.10 Environmental and Social Protection Requirements The civil construction and ancillary works is anticipated to generate both beneficial and adverse impacts of varying degree on the existing environment. It is important to implement strategies and techniques to control the extent of environmental impacts to acceptable levels. The Contractor is required to take necessary actions or mitigation measures to eliminate or minimise adverse environmental impacts. The mitigation measures identified by S.O. shall be implemented by the Contractor during the construction Stage. The Contractor shall comply in all respects with the Conditions of Approval issued by Jabatan Alam Sekitar as detailed in EIA Approval letter if any. (a) Soil Erosion One of the major impacts identified during site clearance and related earthworks activities is soil erosion and related problems such as increased silt loads and sedimentation rates. The extent of soil erosion as a result of these activities shall be minimised through the implementation of the following mitigation measures. The approach taken to erosion and sediment control shall incorporate: -
exposure of the smallest practical area of land for the shortest time possible;
-
application of adequate erosion and sediment control measures within the Site boundary and downstream areas; and
-
implementation of a thorough maintenance and follow-up programme to ensure the effectiveness of the control measures.
Selective Clearance The foremost approach to counter soil erosion problems shall be to undertake land clearance in sections or stages, thereby reducing the surface area exposed to the weather at any one time. In addition, by compartmentalising the felling of trees from high to low ground, the remaining vegetation can act as silt barrier. This strategy shall be best approached through advance planning of the works especially in the coordination between clearing works, supply of equipment and materials and execution of construction works to avoid undue delays of the project schedule. Stormwater Diversion Temporary stormwater diversion ditches shall be adequately installed prior to the construction works to divert stormwater from any exposed areas which may otherwise aggravate soil detachment leading to soil erosion and landslides. Upon completion of the construction works and when demobilisation activities take place, the diversion ditches which are not submerged by the reservoir shall be revegetated. Silt Traps and Sedimentation Ponds Silt traps and sedimentation ponds shall be strategically installed prior to land clearance activities and earthworks. These silt control structures are essential to intercept any run-off from the site before entering the receiving waterways thus reducing sediment loads into the watercourses.
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Any discharges from the sedimentation ponds into the watercourses shall not contain suspended solids of more than 50 mg/l. Regular desilting and maintenance of the silt traps and sedimentation ponds is necessary to ensure effectiveness of the silt control measures. These structures when no longer in use, shall be removed and the ground reinstated and revegetated. Revegetation/Ground Cover During land clearance and construction stages, topsoil, turf and other suitable vegetation shall be placed as immediate temporary cover on all exposed surface areas which are not going to be inundated. Methods such as coconut matting and hydroseeding shall be adopted. This will minimise erosion of stripped or cut soil while making provision for permanent ground cover. In addition, plastic, PVC covers or other protection structures which are impervious to water shall also be temporarily used on all exposed surfaces, particularly on sloping areas. (b) Materials Handling and Disposal of Waste Material Soil contamination at the material storage and vehicle maintenance areas shall be avoided through proper storage and handling of materials such as fuel, lubricants and chemicals. During the demobilisation stage, all equipment and vehicles used during the construction activities shall be removed from the Site. Liquid wastes are also required to be removed from the Site and disposed in a proper manner by a licensed waste collector. Civil construction works is expected to generate substantial quantities of waste material. Necessary actions shall be adopted to reduce and dispose of unwanted materials, the waste material shall be disposed at a pre-selected disposal site as approved by the local authority. (c) Landuse and Aesthetics During the construction phase, temporary structures and exposed areas such as the storage and borrow areas, shall be minimised in order to reduce the impact on the aesthetics of the general environment. The project site will need to be rehabilitated at the end of the construction phase. Therefore, the arrangement of temporary structures shall be considered during the planning stage incorporating detailed rehabilitation plans for these areas. Surplus excavated material and construction waste generated from the excavation works shall be disposed of. As much of the material as possible shall be processed for use in the construction works. It should be noted that the disposal of spoil requires written consent from the DOE as legislated in Section 24 of the Environmental Quality Act 1974 (Act 127). In general, the selected sites for the disposal of spoil shall be located where they will not cause siltation problems in the streams. Where necessary, the waste piles shall be levelled and turfed or landscaped to prevent erosion. Strategic locations shall be opted for construction of temporary access or haul roads to the construction siter. The construction of access roads to the construction sites shall be limited as much as possible to avoid excessive land conversion. This will also minimise the short term visual and soil erosion impacts on the existing environment. It is expected that re-establishment of vegetation will occur in the areas previously cleared during the construction stage. Exposed slopes shall be immediately revegetated, both for erosion control and to maintain a visually pleasing appearance at the dam site. (d) Road and Traffic
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The road and traffic impacts shall be mitigated by adopting the following measures: -
provide temporary and permanent drainage works along with the road construction activities to avoid localised flooding;
-
provide adequate manpower, sign boards and advance notices of imminent inconvenience to the public road users to reduce traffic flow interruptions and to regulate the traffic movements;
-
appoint authorised personnel to co-ordinate with the local traffic and road authorities to plan and control the movement and schedule of the construction vehicles; and
-
immediate turfing, hydromulching or other slope protection measures need to be carried out to reduce slope failures or landslides.
(e) Air Quality, Noise and Vibration The potential air quality impacts of construction civil works are mainly related to dust particles expected to be generated during the construction stage. The air quality impacts shall be mitigated by implementing the following dust suppression measures: -
maintaining and upkeeping all major haul routes;
-
wetting of stockpiles, exposed and uncompacted areas;
-
wetting of all access routes and spraying vehicle wheels at the construction route before entering into the main road;
-
covering construction material loads of the transporting vehicles with PVC sheets or other means of coverage; and
-
turfing and revegetating of all exposed areas.
Face masks shall be provided for the construction site workers and personnel. Necessary actions are required to be taken to minimise noise and vibration impacts through the adoption of the following measures: -
provide safety goggles and protective hearing devices for construction workers when handling equipment with potential noise hazards;
-
limit operating hours for isolated high noise activities such as pile driving, rock blasting and tree cutting, etc.;
-
install warning signboards to indicate high noise areas; and
-
transportation of heavy loads of construction materials, machineries, etc. to be undertaken preferably during off-peak traffic hours.
(f) Hydrology and Hydraulics Regime Installation of silt traps and sedimentation ponds shall be carried out before the land clearance to reduce the silt loads which can potentially alter the hydrology and hydraulic regime of rivers adjacent to the construction site.
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The land clearance and earthwork activities shall be carried out in sections to reduce the area exposed to rain and wind action which may increase soil erosion rates. Frequent desilting of the silt traps shall be undertaken to ensure efficient performance. Revegetation of bare earth shall be carried out to control surface runoff, silt loading, slope protection as well as landscaping purposes. Culvert and cofferdams shall be installed at strategic locations during the construction period to control construction floods. These structures shall be designed for a 1 in 25 year return period. Proper temporary and permanent drainage shall also be provided prior to the construction activities and continuously maintained up to operational phases of the project to ensure efficient removal of stormwater. (g) Water Quality Implementation of slope protection measures and soil erosion control can minimise the siltation of waterways during the site preparation period. The loading of high silt concentrations into the rivers downstream of the Site shall be reduced by constructing silt traps at the outlet of water discharge points from the construction sites. This will safeguard the deterioration of water quality in the rivers downstream of the Site. Proper sanitation facilities that comply to the specifications set by the Ministry of Health shall be provided at the construction workers camp. As much as possible of the vegetation in the proposed reservoir area shall be removed to reduce the possibility of the decomposition of residual vegetation leading to anaerobic conditions in the reservoir water. In order to maintain river water quality, wastewater generated during the construction phase shall be treated before discharging into the receiving waters. Since there are water supply intakes located downstream of the project sites, the wastewaters shall have to be treated to Standard A of the Environmental Quality (Sewage and Industrial Effluents) Regulations of 1978 prior to discharge. (h) Aquatic Resources The biodiversity of aquatic organisms are influenced by the water quality of the river system. As such, the proposed mitigating measures undertaken to reduce the impacts on river water quality will also be beneficial for the sustenance of the aquatic ecosystem. During reservoir impounding compensation flows shall be released to maintain flows in the downstream river channel in consideration of the aquatic life and other riparian users. (i) Terrestrial Fauna The reservoir area shall be cleared of its vegetation in such a manner that the animals and birds can be driven up the slopes and be allowed to escape into adjacent forest reserve areas. To be effective in driving the animals and birds out of the reservoir area, clearing work shall begin at the dam site working up the valley towards the upper parts of the Sg. Jus catchment. (j) Public Health In order to avoid potential health problems during the construction period, the following mitigation measures shall be adopted: -
screen all construction workers for communicable diseases;
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-
provide a sufficient supply of clean water to the construction site and base camps;
-
provide adequate sanitation facilities at the construction site to prevent bacteriological contamination of downstream river water;
-
provide proper waste disposal systems to prevent the breeding of mosquitoes, rats and other pests; and
-
carry out periodic vector surveys at the construction site.
1.11 Health, Safety and Environmental Occupational Safety and Health Act 1994 The Contractor shall comply with the relevant requirements of this Act. The Contractor shall appoint a Safety Officer and set up Safety Committee. Compliance with the requirements of this section of the Specification by the Contractor shall not relieve the Contractor from responsibility to comply fully with the provisions of the Act, and for the safety of his workers and employees and those of his sub-contractors. Failure to Comply In the event that the Contractor fails to comply with the requirements of the Act or with the Specification in respect of safe working conditions or practices on the Site, the S.O. shall have the authority to instruct the Contractor to stop work in any particular location until the unsafe conditions or practices have been rectified to the satisfaction of the S.O. In this event, the Contractor shall be responsible for all costs and delays resulting from complying with such instruction by the S.O. and for the actual costs incurred on rectification of the unsafe conditions or practices. Contractor’s Safety Plan The Contractor shall establish a health and safety plan to show how the Contractor will carry out the Works in a safe and hygienic manner and complying with all laws, regulations, codes of practice and other things relevant to health and safety that may from time to time apply to the Works. Within fourteen (14) days of the date of the Letter of Award the Contractor shall produce and submit to the S.O. an outline Health and Safety Plan. Within twenty-one (21) days thereafter the Contractor shall submit to the S.O. for approval a detailed Health and Safety Plan that shall take proper account of the S.O.’s comments on the outline Health and Safety Plan. The Contractor shall implement the procedures set out in the approved Health and Safety Plan. The Contractor shall prepare and submit to the S.O. for approval a Safety Plan specific to the work to be carried out under the Contract. The Contractor shall carry out all work on the Site in accordance with the approved Safety Plan. The Safety Plan must include the safety objectives and the proposed outline for carrying out this objectives. The safety plan must also include procedures for training of site personnel on all safety procedures and induction courses for new staff. The system for accident reporting and investigation must be fully elaborated in the safety plan. Contractor’s Safety Officer
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The Contractor shall appoint a qualified and experienced Safety Officer for the duration of the Contract. The full time duty of the Safety Officer shall be the prevention of accidents and enforcement of the requirements of legislation in force. The name and qualifications of the Safety Officer so designated shall be submitted to the S.O. by the Contractor for approval within two (2) weeks of the date of the Letter of Award. The Safety Officer shall attend full time on site during normal working hours and whenever work is in progress during out of hours working, public and national holidays approved by the S.O. and available by phone and cellular phone during non-working hours. The Safety Officer shall be registered with DOSH and shall possess, as a minimum requirement, certificates of attendance at relevant safety training courses operated under the auspices of the Factories & Machinery Department or similar government bodies. In the absence of such certificates of formal relevant training the proposed Safety Officer will be required to attend and complete a Short Course in Safety Training operated under the auspices of the National Institute of Occupational Safety and Health (NIOSH). Contractor’s Safety Committee The Contractor shall set up a Safety Committee comprising the Safety Officer, project manager, site agent, S.O’.s site representatives and foremen for the Contract. The committee shall meet weekly and minutes shall be recorded and a copy shall be submitted to the S.O. The S.O. shall be invited to be present at the Safety Committee’s meetings. Site Safety Committee The Contractor shall appoint a representative, whose appointment shall be approved by the S.O, to the Site Safety Committee which shall be set up to coordinate safe working practises of the various subcontractors. Unless otherwise permitted by the S.O., the Contractor’s representative shall be the Contractor’s full time safety officer or part time safety officer as appropriate. The composition of the Site Safety Committee shall be: -
the S.O. or his representative Project Manager Site Agent Safety Officer
The purpose of the meetings will be to discuss and resolve safety aspects of the various parts of the work, including possible areas of conflict or difficulty. Where different sub-contractors are working in the same area of adjacent areas, or where the work of one may impinge upon the work of another, the meetings will consider what action needs to be taken to ensure each sub-contractor is aware of the safety requirements of others. First Aid Facilities The Contractor shall provide a complete Red Crescent first aid outfit and shall keep it in a metal box in his site office. The outfit shall be in the charge of either the Contractor’s Safety Officer or some other responsible person who will also be on the site during all working hours to ensure that the first aid outfit is available without delay at all times when work is in progress. The Contractor shall also provide a first aid outfit in the office for the S.O. There shall be provided at all times and at suitable locations equipment for promptly rescuing persons from the water and resuscitating rescued persons.
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The Safety Officer and another senior member of the Contractor staff shall be trained in simple first aid duties including resuscitation of persons rescued from drowning. The Contractor shall comply fully with all rules and regulations form time to time issued and orders given by the Health Ministry or the local medical or sanitary authorities. Overhead Hazards Every place where persons are required to work or to pass that is normally exposed to falling material or objects shall be provided with suitable overhead protection, and where no one is required to work or to pass but employees are at work in the vicinity such exposed area shall be roped off or other-wise guarded against inadvertent entry. Falling Hazards Every hole into or through which a person may fall shall be covered by a temporary cover fixed securely in position or guarded by an effective barrier to prevent falls except where free access is required by work actually in progress. In such a case where work is in progress, the barrier shall be maintained in position to the extent possible, and suitable warning signs shall be erected. Drowning Hazards Where the work involves filling tanks with water leaving an open surface, the Contractor shall provide at all times and at suitable locations equipment for promptly rescuing persons from the water and resuscitating rescued persons. Slipping Hazards The Contractor shall not suffer or permit an employee to use a passageway, or a scaffold, platform or other elevated working surface which is in a slippery condition. Oil, grease, water and other substances causing slippery footing shall be removed, sanded or covered to provide safe footing.
Tripping Hazards All passageways, platforms and other places of work shall be kept free from accumulations of dirt and debris and from other obstructions that may cause tripping. Sharp projections shall be removed or covered. Access to Workplace Temporary stairways, ramps or runways shall be provided as the means of access to working levels above or below ground except where the nature or progress of the work prevents their installation, in which case ladders or other safe means shall be provided. The Contractor shall not assume that access arrangements provided by another Contractor or by the Employer will necessarily remain in place after the time that the Contractor commences work in a particular area. Dust and Gases Dust and gases shall be controlled by ventilation or otherwise so as to prevent concentrations tending to injure health or obstruct vision or from exceeding safe levels.
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Corrosive Substances All alkalis, acids and other corrosive substances shall be so stored and used so as not to endanger employees. Suitable protective equipment for the use of such substances shall be provided. Clean water supply shall be readily available for washing off any spillage of any corrosive substance on the employees. Eye Protection Suitable eye protection equipment shall be provided for and shall be used by employees while engaged in welding or cutting operations or in chipping, cutting or grinding any material from which particles may fly, or while engaged in any other operation which may endanger the eyes. Respirators Where required the Contractor shall provide and the employee shall use a respirator suitable for the type of operation for which it is to be used. The Contractor shall maintain such respirator in good repair and shall furnish the means for its continued efficient working condition. The Contractor shall provide regular inspection, cleansing and sterilisation of such equipment. Such equipment when not in use shall be store in a closed container. The equipment shall be either of the escape set type, where it is provided for possible emergency use, or self contained breathing apparatus where work has to be carried out in conditions where toxic gases are present or where there is a deficiency of oxygen. All persons who may be required to use equipment shall be adequately trained and shall have certificates to that effect. Work in Confined Spaces Where work is required to take place in a confined space, defined as an enclosed space with limited access and where there is no natural ventilation, the Contractor shall provide equipment for monitoring the quality of the air within the space. The equipment shall be used to check the atmosphere before personnel enter, and shall remain in place while work is in progress to ensure that the confined space is free of harmful or noxious gases. The Contractor shall not permit anyone to enter or work in a confined space, including personnel from other Contractors, the S.O. staff or the Employer’s staff if harmful or noxious gases are detected. Any personnel inside shall be evacuated immediately. All personnel working in such conditions shall be provided with escape sets. The Contractor shall provide a “top-man” who shall be stationed immediately outside the entrance to the confined space, and who shall maintain communication with personnel working inside the confined space, and who shall have means for raising the alarm in case of any emergency inside the confined space. Harnesses and ropes etc. shall be provided to enable unconscious personnel to be brought out of the confined space in an emergency. The Contractor shall provide adequate ventilation for workers carrying out work inside a confined space, pipeline or chamber or other enclosed areas by using blowers or other suitable means. Trolleys attached to ropes shall be provided for persons moving within the pipeline. Protective Clothing
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Every employee shall be provided with a safety helmet of a type tested and approved by SIRIM, and shall be required to wear it while working on the Site, except in the Contractor’s office. Every employee required to work in water, wet concrete or other wet footing shall be provided with suitable waterproof boots. Every employee required to use or handle alkaline, acid or other corrosive substances shall be provided with appropriate protective clothing. Electrical Hazards Before work commences, the Contractor shall ascertain by inquiry or direct observation, or by instruments, where any part of an electric power circuit exposed or concealed is so located that the performance of the work may bring any person, tool, or machine into physical or electrical contact therewith. The Contractor shall post and maintain proper warning signs to his employees of the location of such lines, the hazards involved and the protective measures to be taken and shall, if practicable, de-energise the electric power circuit.
The Contractor shall not suffer or permit an employee to work in such proximity to any part of an electric power circuit that he may contact the same in the course of his work unless the employee is protected against electric shock by de-energising the circuit and earthing it or by guarding it, by effective insulation or other means acceptable to the S.O. or relevant authority. In work areas where the exact location of underground electric power lines is unknown, employees using jack-hammers, bars or other hand tools which may contact a line shall be provided with insulated protective gloves and footwear. Power Driven Saws All portable power-driven hand operated saws shall be equipped with guards above the base plate which completely protects the operator from contact with the saw blade when in motion and with selfadjusting guards below the base plate which completely covers the saw to the depth of the teeth when the saw is removed from the cut. Public Vehicular Traffic Whenever any work is being performed over, on or in proximity to a highway or any other place where public vehicular traffic may cause danger to men at work, the working area shall be so barricaded as to direct traffic away from it or the traffic shall be specially controlled by persons designated for that purpose. All vehicles used at the worksite must be roadworthy and registered with the appropriate authority. No person shall drive a vehicle at the worksite unless he is the holder of the appropriate driving licence. Stability of Structures No section of the plant or other structure or part of a structure shall be left unguarded in such condition that it may fall, collapse or be weakened due to wind pressure or vibration. Storage of Materials and Equipment
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All materials shall be stored or stacked in a safe and orderly manner so as not to obstruct any passageway or place of work. Material piles shall be stored or stacked in such a manner as to ensure stability. Disposal of Debris Debris shall be handled and disposed of by a method which will not endanger persons. Debris shall not be allowed to accumulate so as to constitute a hazard. Excavations No employee shall be permitted to enter any excavated area, including areas excavated by other contractors on the Site, unless sheet piling, shoring or other safeguard that may be necessary for his protection is provided. Where any employee in an excavation is exposed to the hazard of falling or sliding materials from any bank or side more than 1.5 m high above his footing, adequate piling and bracing shall be provided against the bank or side to eliminate such hazard. The excavation and its vicinity shall be checked by a designated person after every rain storm or other hazard-increasing occurrence and the protection against slides and cave-ins increased if necessary. Shoring adequate to support the overhanging material shall be provided where banks are undercut. Excavated material and other superimposed loads shall be placed at least 1 m back from the edge of open excavations and trenches and shall be so shored or retained that no part thereof can fall into the excavation, or cause the banks to slip or cause the upheaval of the excavation bed. Banks shall be stripped of loose rock or other materials which may slide, roll or fall upon persons below. Open slides of excavations where a person may fall more than 3 m shall be guarded by adequate barricades, and suitable warning signs shall be put up at conspicuous positions. No employee shall be suffered or permitted to work where he may be struck or endangered by an excavating machine or by material dislodged by it or falling from it.
Ladders, Step Ladders and Access Platforms Every ladder, step-ladder and access platform shall be of good construction, sound material and adequate strength for the purpose of which it is used. Ladders, step-ladders and access platforms shall not stand on loose bricks or other packing, but shall have a levelled and firm footing. Positioning of Machinery No person shall be permitted to position or operate machinery in a manner likely to endanger himself or others. Cranes
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Cranes shall be so constructed, positioned and operated as to be stable. No crane shall be loaded beyond the safe working load except by an approved person or an inspector for the purpose of testing such machine. Every crane including all blocks, shackles, sheaves, wire ropes and the various devices on the mast and jib shall be thoroughly inspected by an approved person at intervals not exceeding 12 months. Cranes shall be inspected before being first erected or operated on each job or after any major repair. Inspection and repair of crane jib shall be made only when the jib is lowered and adequately supported. Outriggers and counter-weights shall be provided and used as specified by the manufacturer of the crane or by an approved person. Counter-weights shall be properly placed and secured. Levelling jacks or other suitable means shall be provided and used with outriggers of truck mounted mobile cranes. Firm and uniform footing shall be provided for cranes. When such a footing is not otherwise supplied it shall be provided by substantial timber, or other structural members sufficient to distribute the load so as not exceed the safe bearing capacity of the underlying material. Every power-operated crane shall be provided with efficient brake or brakes or other locking devices which will prevent the fall of the load when suspended and by which the load can be effectively controlled whilst being lowered. Hand or foot-operated bakes shall be provided with a substantial locking device to lock the brake in engagement. No load-bearing part of any crane shall be replaced by another part, and no such machine shall be modified by the addition thereto or removal therefrom of any load bearing part, unless the replacement or modification shall be certified by either the manufacturer or the approved person who tested the crane. A capacity chart shall be provided for every crane. Such chart shall be posted and maintained in a place clearly visible to the operator and shall set forth the safeloads for various lengths of jib at various jib angles and radial distances. Where outriggers are provided such loads shall be set forth with and without the use of outriggers. Unless furnished by the manufacturer or builder of the crane, a capacity chart shall be prepared and certified by an approved person. A crane shall not lift any load that exceeds the corresponding safe working load specified by its capacity chart. Every crane having a jib shall be provided with an accurate indicator which shows, clearly to the operator, the radius of the jib and the safe working load corresponding to that radius at all times and gives warning signal when the radius is unsafe. Before hoisting any load at a new job site, the jib shall be operated to its maximum height. Crane cabs shall be locked when the operator is not present and no unauthorised person shall enter the cab or remain immediately adjacent to any crane in operation. If locking of a crane cab is impracticable, the operating mechanism shall be locked so as to prevent the crane from being operated by an unauthorised person.
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No crane shall be operated in such a location that any part of the cane or of its load in any position of jib or swing may come within 3 metres of live power lines: Attachment of Loads Where a sling is employed to hoist long-length material, a lifting beam shall be used to space the sling legs for proper balance. When load is suspended at two or more points with slings, the eyes of the lifting legs of the slings shall be shackled together and this shackle or the eyes of the lifting legs may be shackled directly on the hoisting block or balance beam. The eyes may be placed on the lifting hook without shackles if the hook is of the safety type. Each container or receptacle used for raising or lowering loose material of any kind shall be so enclosed, constructed or designed as to prevent the accidental fall of such material. Crane loads shall be raised vertically so as to avoid swinging during hoisting. No crane shall travel with a suspended load except upon a safe runway. During travel without loads, cranes falls shall be secured or place so as to prevent accidents or damage by swinging.
1.12 The Site The limits of the lands available to the Contractor for the purpose of the Works are shown on the Drawings or as specified. The Contractor shall be deemed to have inspected the Site in accordance with Clause 15 of the Conditions of Contract to ascertain the site conditions such as the topography, vegetation, drainage, weather conditions, means of access and any other contingency liable to affect his construction of the Works. Claims will not be entertained by the S.O. for any extra costs incurred by the Contractor in carrying out the Works on the ground of ignorance of the site conditions, or the conditions under which the Works will be executed.
1.13 Access to the Site Access to the site can be gained from the existing roads from where access roads shall be constructed under the Contract or temporary access roads constructed by the Contractor.
1.14 Working Space and Work through Private Land Land Acquisition for Permanent Works In the case where Works are to be constructed through private land, the Employer will make available the land and the limits of the land which will be available for the construction of the Works are shown on the Drawings. The Contractor will not be allowed to exceed the limits of the land shown on the Drawings. Temporary Access The Contractor shall be responsible for obtaining the consent of the owner, tenant, or occupier of private land to the use of such land or private roads for temporary access to the work site or for other temporary purposes. Before entering upon private land for the purpose of commencing construction the Contractor shall confirm in writing to the S.O. that he has obtained this consent.
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The Contractor shall pay all costs, expenses, rentals, compensation or other disbursement which may be incurred by him in negotiations with the owner, tenant or occupier and during the subsequent use by him of such private land or roads for these purposes. No reimbursements will be made to the Contractor in this respect. The full cost thereof shall be deemed to be included in the Contract Rates. The Contractor shall note that his responsibility shall apply to the whole of the land occupied or used by him for the purpose of the Works, whether within or without the working space defined above. The Contractor shall be held responsible for all damage which he may do to land or property lying outside the working space as defined above. Compensation for damage to such land or property caused by the Contractor will be assessed by the Collector of Land Revenue for settlement by the Contractor through the Employer. The Employer will be entitled to withhold from any payments due to the Contractor sufficient sums as may appear to him to be necessary to cover the Contractor's liabilities until evidence is produced by the Contractor to the S.O. to show that the Contractor's liabilities in this respect have been finally settled and discharged.
1.15 Trespass on Adjacent Property In carrying out the Works, due regard shall be paid to the amenities of adjacent property and to the interests of owners, tenants and occupiers. The Contractor shall take adequate steps to prevent trespass by his employees and shall be wholly responsible for making good any loss or damage caused by such trespass.
1.16 Existing Services The Contractor shall be responsible for the security of all water, electricity, telephone, sewerage and other services, drains, pipes and other apparatus belonging to or under the control of any public authority, company or person, which may be, or be liable to be, interfered with, by or in connection with the execution of the Works. The Contractor shall fully indemnify the Employer against any claim, action, expense, loss, damage or injury arising in this respect.
1.17 Works in Roads and Footpaths Where work is carried out in or adjacent to public or private roads, footpaths or verges the Contractor shall comply with the regulations in force in the place. If the Contractor's work will cause unavoidable interference with access to adjoining property the Contractor shall give seven days notice in writing of such interference to the occupier of such property and shall, before interfering with the existing access provide temporary means of access for vehicles and pedestrians. Where the Contractor wishes to obtain any partial or complete road closure he shall make all the proper arrangements with the appropriate persons or authorities. The Contractor shall also provide all apparatus and men required for adequate traffic control lighting, watching and fencing to the satisfaction of the S.O., local authority and police. The Contractor shall note that the works may be required to be executed outside the normal working hours as required and such works as carried out
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shall not be considered as ordered overtime working. He shall comply fully with all requirements of these authorities before commencing and during any excavation in roads. Any damage to the roads and paths caused by the Contractor's vehicles shall be made good at his own expense. The Contractor shall carry out such maintenance as to keep the roads and paths clean and clear of any loose materials, debris, earth and the like deposited by his vehicles. In respect of this Clause, the Contractor shall bear the full responsibility for all the costs of any such arrangement and these costs shall be deemed to have been included in the Contract Rates and shall indemnify the Employer against any claim whatsoever arising therefrom.
1.18 Claims for Damage to Person or Property Any claim received by the Employer or S.O. in respect of matters in which the Contractor is required under the Contract to indemnify the Employer will be passed to the Contractor who shall likewise inform the S.O. of any such claim which is submitted directly to him by a claimant. The Contractor shall do everything necessary, including notifying the insurers of claims received, to ensure that all claims are settled properly and expeditiously and shall keep the S.O. informed as to the progress made towards settlement, failing which the Employer shall be entitled to make direct payment to claimants of all outstanding amounts due to them in the S.O.'s opinion and without prejudice to any other method of recovery to deduct by way of set-off the amounts so paid from any sums due or which shall become due from the Employer to the Contractor. Nothing contained therein above shall relieve the Contractor of his obligations and responsibilities under the Contract. If the Contractor receives a claim which he considers to be in respect of matters in which he is indemnified by the Employer under the Contract he shall immediately pass such claim to the Employer.
1.19 Amenities to be Preserved The Contractor shall not cause interference with existing amenities, whether natural or man-made. No trees shall be felled except on the instructions of the S.O. and clearance of vegetation of any sort shall generally be kept to the minimum necessary for the Works and Temporary Works.
1.20 Works to be Kept Clear of Water The Contractor shall keep the Works clear of water at all times during construction and erection of plant by others and at all such times during the Defects Liability Period as shall be required by the S.O. The Contractor shall construct, operate and maintain all temporary dams, cofferdams, watercourses and other works, and shall carry out all pumping, that may be necessary to exclude water from the Works while construction and erection is in progress. All such temporary works shall be removed at a time approved by the S.O. when the Works are completed.
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Notwithstanding any approval by the S.O. of the arrangements made for the exclusion of water, the Contractor shall be held responsible for the sufficiency thereof, and shall be liable for keeping the Works safe during all floods, and for making good at his own expense any damage to the Works that may be attributed to floods. Any loss of production, additional overheads, or additional costs of any kind that may result from floods shall be at the Contractor's own risk. Floods shall not be deemed to be an "excepted risk". All costs incurred by the Contractor in complying with the requirements of this Clause shall be deemed to be included in the Contract Rates.
1.21 Discharge of Water and Waste The Contractor shall make provision for the discharge or disposal from the Works and temporary works of all water and waste products howsoever arising and the methods of disposal shall be to the satisfaction of the S.O. and of any Authority or person having an interest in any land or watercourse over or in which water and waste products may be so discharged. The requirements of this Clause shall not limit any of the Contractor's obligations or liabilities, particularly as to Clause 32 of the Conditions of Contract.
1.22 Temporary Fencing The Contractor shall erect, maintain and remove suitable and approved temporary fencing to enclose such areas of the Works, Temporary Works and all areas of land occupied by the Contractor within the Site as may be necessary to meet his obligations under Clause 32 of the Conditions of Contract and as directed by and to the satisfaction of the S.O. Where any temporary fence has to be erected around the Site, alongside a public road, footpath, etc, it shall be of the type required by and shall be erected to the satisfaction of the authority concerned.
1.23 Temporary Works Construction and Design The Contractor shall submit to the S.O. for approval drawings and full particulars of all Temporary Works which he intends to construct. Adequate time shall be allowed for checking such drawings and particulars before it is desired to commence constructing such works. The submission to or approval by the S.O. of any such proposals by the Contractor shall not relieve the Contractor of any of his responsibilities for the sufficiency of the Temporary Works for their intended purposes. The Contractor shall provide, maintain and remove on completion of the works all necessary temporary works including but not limited to temporary traffic diversions, roadways, crossings, footpaths, accesses, drains, stagings, scaffoldings and other temporary supports to enable the constructional operations to be performed in the appropriate sequence. All temporary works proposed shall be properly designed and constructed to carry out the loads to which they will be subjected and all drawings and calculations pertaining thereto shall be forwarded to the S.O. for approval. Notwithstanding the approval by the S.O. of any submitted design for any temporary works the Contractor shall remain wholly responsible until the removal of such works for their efficiency, security and maintenance and for all obligations and risks in relation to such works specified or implied in the Contract and shall reinstate the same at his own expense should any mishap or accident
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occur causing damage or injury thereto subject to any provisions of the Conditions of Contract as may be applicable in case of such damage or injury. Except where specific provision is made in the Bill of Quantities for payment to the Contractor for temporary works the cost of complying with the requirements of this clause shall be deemed to be included in the tender rates and prices.
1.24 Water Supply All water for use on the Works shall be fresh and free from harmful impurities to the satisfaction of the S.O. The Contractor shall make adequate arrangements to deliver sufficient water to the Site for drinking, washing, sanitation and general cleaning down, in addition to any required for the construction, watertightness testing, sterilisation and flushing.
1.25 Power Supply The Contractor shall make his own arrangements for the supply of electricity to and about the Site for the construction, of the Works and for his own use during the Defects Liability Period. The Contractor shall comply with all local authority regulations applicable to the use and storage of diesel oils, petrol, paraffin and other inflammable fuels and engine driven generators used by him on the Site, and shall ensure that adequate precautions are taken against fire. Permanent fencing and other safeguard required to be erected around electrical equipment shall be to the standards required by the Tenaga Nasional Berhad before any connection to the public supplies can be made.
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1.26 Temporary Sanitary Conveniences The Contractor shall provide all proper temporary conveniences for his workmen. These conveniences shall consist of flush system closets and the sewerage shall be discharged to septic tanks or Imhoff tanks. All such arrangements shall meet all the requirements as stipulated by the local Health Authority and the Contractor's proposals shall be submitted to and approved by the S.O. The Contractor shall maintain the Site and all working areas in a hygienic condition and in all matters of health comply with the requirement of the local Health Authority.
1.27 Site to be Kept Tidy Throughout the progress of the Works, the Contractor shall keep the Site and all working areas in a tidy and workmanlike condition and free from rubbish and waste materials. Any temporary works, construction plant, materials or other things which for the time being are not required for use by the Contractor may with the consent of the S.O. be removed from the Site but otherwise shall be dispersed about the Site in an orderly fashion and shall be properly and securely stored thereon. The Contractor shall make safe and reinstate all areas affected by temporary works.
1.28 General Hygiene and Medical Examination of Contractor's Employees Before commencing work on the Site the Contractor shall ensure that all his employees are instructed in the necessity for the prevention of pollution. The Contractor shall immediately dismiss and remove from the Site any employee or representative of the Contractor who has been polluting or fouling the Site or any of the water supply installations and shall take appropriate remedial measures to prevent a repetition of the occurrence and to disinfect the areas concerned all to the satisfaction of the S.O. The Contractor shall not employ upon the Site, or on periodic visits thereto, persons who are known to have any disease which could be water-borne or who is suffering from an illness associated with looseness of the bowels or who are carriers of typhoid bacillus or other potential pathogenic organisms or who are otherwise unsuited on medical grounds to be employed in or around water supply installations. The Contractor shall if and when required to do so, arrange for his employees to be examined and tested in the manner approved by the Government's Medical Officer of Health. The Contractor shall immediately remove from the Site any such employees who as a result of such examination and testing may in the opinion of the Medical Officer or the S.O. constitute a danger to water supplies or who refuse to undergo an examination.
1.29 Temporary Buildings for Use by Contractor The Contractor shall provide such temporary offices, buildings, tanks, etc, as may be necessary and proper for his general use in connection with the Works, and for the use of persons employed by him. The nature of the offices, buildings, tanks, etc, and the positioning of them shall be subject to the prior approval of the S.O.
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The Contractor shall maintain all offices, buildings, tanks, etc, referred to in this and succeeding clauses in good condition and comply with all the requirements of the Local Authorities in whose area they are situated.
1.30 Temporary Offices for the S.O. and His Staff The Contractor shall supply, paint and furnish temporary site offices for the S.O. and his staff in approved locations to be provided by the Contractor. The site offices as approved by the S.O. shall be constructed and maintained by the Contractor.
1.31 Transport for S.O. and His Staff The Contractor shall provide and keep available at all times during the period of execution of the Works and such times until issuance of the Certificate of Practical Completion as shall be required by the S.O. for the sole use of the S.O. and his staff in the performance of their duties the motor vehicles as described in Bill of Quantities.
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Section 2 - Earthworks
2.0
EARTHWORKS
2-1
2.1
Definitions
2-1
2.2
Levels to be Recorded
2-2
2.3
Explosives and Blasting
2-3
2.4
Disposal of Materials
2-4
2.5
Excess Excavation to be Made Good
2-4
2.6
Site Clearance
2-4
2.7
Trees
2-5
2.8
Stumps
2-5
2.9
Stripping Topsoil
2-5
2.10
General Excavation
2-5
2.11
Excavation of Cuttings (Bulk Excavation)
2-6
2.12
Excavation below Embankments and below Formation Level in Cuttings
2-6
2.13
Trench Excavation
2-7
2.14
Trench Excavation in Roads, Road Shoulders and Footpaths
2-8
2.15
Trench Excavation in Fields, etc.
2-8
2.16
Rock and Other Materials in Excavations
2-9
2.17
Supporting Excavation
2-9
2.18
Trimming Excavations
2-9
2.19
Inspection of Excavation
2.20
Filling to Embankments and Backfilling to General Excavation 2-10
2.21
Compaction of Embankments and Other Areas of Fill
2-11
2.22
Earthworks to be Kept Free of Water
2-13
2.23
Embankments on Soft Soil
2-13
2.24
Trenches Not to be Left Open
2-14
2.25
Refilling Trench Excavation
2-14
2.26
Spoil Tips on the Site
2-15
2.27
Treatment of Material from Excavation
2-15
2.28
Surface Reinstatement in Road Verges, Fields, etc.
2-16
2.29
Works in Roads and Road Reserves
2-16
2.30
Surface Reinstatement in Roads and Footpaths
2-17
2.31
Other Structures in the Pipeline
2-17
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2.32
Land Drains
2-17
2.33
Care of Existing Services
2-18
2.34
Hedges, Fences and Walls
2-19
2.35
Crossing Watercourses, etc
2-19
2.36
Top Soiling
2-19
2.37
Turfing
2-19
APPENDIX 2.1 :
Gradation Curves for Filters, and Rip-Rap Materials for General Filling
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2.0 Earthworks 2.1
Definitions
The following terms shall have the meanings hereby assigned to them:"Topsoil"
Means any surface material, suitable for use in soiling areas to be grassed or cultivated.
“Unsuitable Material”
Unsuitable material, shall include :-
i)
running silt, peat, logs, stumps, perishable or toxic material, slurry or mud, or
ii)
any material - consisting of highly organic clay and silt; - which is clay having a liquid limit exceeding 80% and/or a plasticity index exceeding 55%; - which is susceptible to spontaneouse combustion; - which has a loss in weight greater than 2.5% on ignition; - containing large amounts of roots, grass and other vegetative matter. - which is soft or unstable because it is too wet or too dry for effective compaction for its intended use.
“Suitable Material”
Suitable material shall comprise all that which is acceptable in a natural or processed state in terms of its intended use to the approval of the S.O.
“Rock"
Means material which in the opinion of the S.O. would normally have to be loosened either by blasting or by the use of pneumatic tools (excluding clay spades worked on an air compressor) or by other rock quarrying methods or, if excavated by hand, by the use of wedge and sledge hammers. An isolated solid boulder or detached piece of rock shall qualify as Rock only if it exceeds 0.30 cubic metre in volume.
“Granular Fill”
‘Granular fill’ shall conform to the grading limits given below :-
BS Sieve Size
10mm 5mm 2mm 600μm 75μm
Percentage by Weight Passing
85 50 10 0
100 to 100 to 100 to 90 to 5
‘Free draining material’ shall consist of hard, clean, crushed rock or gravel having the
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“Free Draining Material”
grading limits specified below. The aggregate crushing value of the material shall not exceed 30%.
BS. Sieve Size
Percentage by Weight Passing
63mm 37.5mm 20mm 10mm
100 85 to 100 0 to 20 0 to 5
"Bulk Excavation”
Means excavation in open cut (excluding Trench Excavation and Incidental Excavation) down to levels specified on the Drawings or otherwise as being the general levels after completion of excavation.
"Trench Excavation”
Means excavation of trenches into which pipes, tubes, cables or drainage materials are to be laid to levels and limits specified in the Drawings or otherwise directed by the S.O.
"Incidental Excavation”
Means excavation below or outside the limits of Bulk Excavation and Trench Excavation.
“Excess Excavation”
Means excavation outside the limits specified or shown on the Drawings or directed by the S.O. for Bulk or Trench Excavation.
All reference to “excavation” or “excavations” shall apply to Bulk, Trench and Excess Excavation(s) except where clearly stated to the contrary.
2.2
Levels to be Recorded
Before the surface of any part of the Site is disturbed or the Works thereon are begun the Contractor shall take and record levels of any such part, in the manner specified or as agreed with the S.O. in the presence of the S.O. and such levels when agreed shall form the basis for measurement. The Contractor shall obtain the S.O.’s prior approval to the proposed methods of obtaining and recording this information and shall afford the S.O. all facilities to attend and check each survey and recording. The Contractor shall give to the S.O. notice of his intention to carry out such survey work at least 24 hours in advance of the commencement of the survey. The Contractor shall carry out, to the satisfaction of the S.O., all extra surveys required to resolve any doubts which may arise as to the correctness of any survey or record and the S.O.’s decision shall be final regarding what shall be recorded as the correct survey. A similar procedure shall be adopted to record any rock surface limits and levels before they are blasted or excavated.
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Each survey drawing with agreed data shall be referred to as a “Record Survey” which shall be signed by the Contractor and the S.O. and shall form the basis for preparation of record drawings of the appropriate work. The Contractor shall supply four copies of each Record Survey to the S.O.
2.3
Explosives and Blasting
The S.O. shall have power to regulate, restrict or prohibit blasting if in his opinion it is necessary to do so for the safety of persons or property or to safeguard the Works. No blasting shall be carried out in any part of the Works without the permission in writing of the S.O. Such permission shall not absolve the Contractor from any of his obligations or liabilities under the Contract and he shall take all necessary precautions including the use of blasting nets to avoid damage, loss or injury to persons and to public or private property. The Contractor shall keep the S.O. fully informed at all times when blasting is proposed to be carried out and of any details that may be required concerning strength of charges and their positions. Explosives shall not be used within 15 metre, or such greater or lesser distances as the S.O. may direct, of concrete placed in the Works, of any existing structure, water main, electric cable, sewer or other services. Notwithstanding the above, all excavations into rock by blasting to prepare foundations for any structures in close vicinity of existing structures shall be carried out with extreme care. Before any rock blasting commences, the Contractor shall submit a detailed controlled blasting plan for the approval of the S.O. The purpose of the control of blasting operations is to eliminate any possibilities of damage to the existing structures. Approval of the Contractor’s proposal shall not absolve him from responsibilities in the event that the existing structures are damaged as a result of the blasting method used. All details regarding the type of explosives or chemicals, strength, spacings, depths, positions of charges, detonation delays used and the method of monitoring the magnitude of vibration generated shall be supplied to the S.O. Pilot tests to assess the effectiveness of the controlled blasting shall be conducted at an approved location within the site before the method is approved. The Contractor shall provide vibration measuring instruments to monitor the magnitude of vibration caused by the proposed arrangements with respect to explosive charges, spacings, detonation delays, etc. The instrument shall be able to measure resultant peak particle velocities from measurement in X, Y and Z planes and record measurements digitally. Sensors shall be mounted at different positions on the existing structures as instructed by the S.O. The instrument shall be a triaxial vibration recorder or similar and shall be capable of measuring velocities in the range of 10-70mm/sec. Blasting operations shall be carried out and supervised only by personnel qualified in and fully conversant with the handling and use of explosive.
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The Contractor shall be responsible for determining the danger zone likely to be created during blasting operations and he shall be responsible for evacuating this area of personnel and placing the necessary safety barriers. The Contractor shall also ensure, by placing heavy blasting mats, or taking similar precautions, when necessary, such that no damage is caused to personnel and property on or off site during blasting operations. The Contractor shall obtain the necessary permits and licences for the use, storage, transport and handling of explosives including providing a store or stores suitable for explosives in accordance with local and national regulations, laws and standards.
2.4
Disposal of Materials
All requirements herein for the disposal by the Contractor of materials arising from site clearance or from excavations are subject to the provisions of the Specification. Suitable materials intended for re-use should be used as soon after excavation as possible. With the approval of the S.O., certain materials may be allowed to be stock piled for re-use. If this is the case, they shall be stock-piled at a location approved by the S.O. Temporary stockpiling shall be such that the properties and composition of materials intended for use as construction materials at a later stage will not change. The influence of stockpiling on ground water, drainage and adjacent structures and services shall be investigated and where necessary suitable measures should be taken. Areas used for temporary stockpiling shall be kept clean and orderly and shall be restored to their original condition before completion of works. Unsuitable materials and suitable material not intended for re-use shall be removed from the work site and disposed off at a location approved by the S.O. Materials shall be disposed off in accordance with local and national laws and regulations including the payment of royalties, fees etc. which may be imposed by the relevant Authorities.
2.5
Excess Excavation to be Made Good
The Contractor at his own expense shall remove from the Site all material resulting from Excess Excavation and shall make good the same with such kind of fill material or in such class of concrete as may be reasonably required by the S.O. having regard to the circumstances.
2.6
Site Clearance
All areas of the Site marked on the Drawings or specified for clearance or from which material is to be excavated or upon which filling is to be deposited shall be cleared to the extent required by the S.O. of all buildings and foundations, walls, gates, fences and other structures and obstructions and of all bushes, hedges, trees, stumps, roots and other vegetation except for trees marked for preservation. Material so cleared shall be disposed of off the Site as directed by the S.O.
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All open burning shall be subject to the prior approval of the relevant Authorities. The Contractor shall obtain the necessary Contravening Licence from the Director-General of Department of Environment, all the burning shall be carried out in conformity with all pertinent regulations. Burning shall only be conducted at times when conditions are considered favourable for burning and at locations approved by the S.O. Materials to be burns shall be heaped neatly and, when in a suitable condition, shall be burnt completely. Heaping for burning shall be done in such manner and at such locations as to cause the least fire risk. A break of 10 m minimum width shall be cleared first along the perimeter of the area to be cleared, to prevent any accidental fire spreading beyond the limits of the areas to be cleared at all times. Then before any burning may commence, another fire break of 20 m minimum width shall be constructed around the perimeter of the heaped piles. No boundary stones, survey pegs, reference markers or temporary bench marks and site investigation markers shall be disturbed from its original position by the Contractor in the course of site clearance and should such stones/markers be disturbed as a result thereof, the Contractor shall be required to reimburse the Government the cost of re-survey and materials etc., which shall be deducted by way of set-off from any sums due or which shall become due from the Government to the Contractor.
2.7
Trees
Trees shall be uprooted or cut down as near to ground level as possible. Branches and foliage shall be removed and disposed of off the Site. Useful timber within Government reserve shall remain the property of the Government and shall be cut into suitable length and stacked properly.
2.8
Stumps
Stumps and roots whether existing or remaining after tree felling shall where directed by the S.O. be grubbed up and uprooted and disposed of off the Site. The resulting hole shall be filled with approved material deposited in 225mm layers and compacted to the same dry density as the adjoining soil. For reservoir clearing before impounding, stumps with diameter more than 0.6 m at 1m above ground level can be left in place provided they do not project more than 1.2m above ground.
2.9
Stripping Topsoil
Where shown in the drawings or ordered by the S.O. topsoil shall be stripped, to such depths and over such areas as he may direct, as a separate operation prior to any further excavation which may be required. Where applicable, turf intended for re-use, as agreed with S.O., shall be taken up in strips of a constant breadth with an approved turfing tool and stock piled in a location approved by the S.O. where it shall be neatly stacked and regularly watered and tended until required for relaying at approved locations. The remaining top soil and turf shall be disposed off the Site as directed by the S.O. and in accordance to the requirements of the relevant authorities.
2.10 General Excavation
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General excavation shall mean excavation required for structures but not include Trench Excavation. The ground shall be excavated by such methods and to such dimensions and depths as shall allow for the proper construction of the Works. Where nominal 'payment' limits of excavation are not shown on the Drawings or otherwise specified they shall be deemed to be the minimum net limits which would allow the outline of the completed structure to be lowered vertically from ground level into its final position. The Contractor shall make his own allowance for any working space required, and any excavation outside the aforesaid limits which has not been ordered by the S.O. whether it be excavated to suit the Contractor’s method of working or unavoidable overbreak or due to his carelessness or error, shall be held to be Excess Excavation.
2.11 Excavation of Cuttings (Bulk Excavation) (i)
The excavation of cuttings shall be carried out in accordance with the Drawings and to the slopes, levels, depths, widths and heights shown thereon.
(ii)
Erosion protection measures as described in Clauses 2.36 and 2.37 shall be carried out as soon as is practicable following trimming of the cut slope, and in any event within 5 days. This time limit applies to each part of a slope or slopes as it is trimmed. The S.O. will not allow excavation of the cutting to progress below any bench until the erosion protection measures have been carried out to his satisfaction on the slope above that bench.
(iii)
Hauling of material from cuttings or the importation of fill material to the embankments or other areas of fill shall proceed only when sufficient compaction plant is operating at the place of deposition to ensure compliance with the requirements of Clause 2.20.
(iv)
Any over excavation below formation level tolerance shall be made good by backfilling with suitable material of similar characteristics, removed and compacted in accordance with Clause 2.20.
(v)
Where the material below the formation level of a cut area is deemed to be unsuitable as subgrade material by the S.O. it shall be removed to a depth to be determined by the S.O. and replaced with suitable material in layers not exceeding 300mm and compacted to 95% (for cohesive material) or 100% (for cohesionless material) of the maximum dry density determined in accordance with BS. 1377, Test 13.
(vi)
The slopes of cuttings shall be cleared of all boulders or rock fragments which move when prised by a crow-bar. Any resultant voids in the slope shall be made good using Class 10/20 concrete, rubble pitching or other means to the satisfaction of the S.O.
(vii)
Constructional traffic shall not use the surface of the bottom of a cutting which has reached formation level unless the cutting is in rock or the Contractor maintains the level of the bottom surface at least 300mm above formation level. Any damage to the subgrade arising from such use of the surface shall be made good by the Contractor at his own expense with material having the same characteristics as the material which has been damaged.
2.12 Excavation below Embankments and below Formation Level in Cuttings
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(i)
Where any material below the natural ground level under embankments, under culvert bedding, or below formation level in cuttings is required to be excavated, it shall be removed to such depth and over such areas as are indicated on the Drawings or as the S.O. shall direct and disposed of in a manner depending on its nature and condition at the time. The resultant excavation shall be backfilled with suitable material deposited in layers of thickness appropriate to the material and compaction plant to be used and compacted in the manner specified for the forming of embankments.
(ii)
If after the removal of material as specified in Sub-Clause (i), the Contractor allows the material so exposed to reach a condition where compaction of backfilling complying with Clause 2.20 is impracticable, he shall make good at his own expense either by additional excavation and filling in the manner specified, or by waiting until the condition of the exposed material is fit to receive the approved backfill.
2.13 Trench Excavation The line and level of trenches shall be as shown on the Drawings or as directed by the S.O. Before commencing Trench Excavation, the route of the trench shall be pegged out accurately and the existing ground levels shall be agreed with the S.O. Strong sight rails shall then be fixed and maintained at each change of gradient and at as many intermediate points as may be necessary. On these rails shall be marked the centre line and the level to which the excavation is to be carried out, such rails being not more than 25 metre apart. Trench Excavation shall be carried out by such methods and to such lines dimensions and depths as shall allow for the proper construction of the Works, provided always that, unless shown otherwise in the Drawings or the S.O. permits otherwise and subject to any specific requirements of the Specification, no Trench Excavation shall be less than the widths stated below:D
Clear width of trench for backfill with excavated material Not exceeding 500mm D + 600mm Exceeding 500mm but not D + 750mm exceeding 750mm Exceeding 750mm D + 900mm
Clear width of trench for sand surround or sand backfill D + 600mm D + 750mm D + 750mm
Note: Where D in mm is the external diameter of the pipe including any sheathing. Notwithstanding the foregoing, any rock in trench excavation shall be so excavated that the clearance between the pipe when laid and the rock sides and bottom of the trench is kept to the minimum limits necessary to provide for the specified thickness of bedding haunching and surround to the pipe. Any excavations outside these limits whether for working space or due to overbreak shall be held to be Excess Excavation. The sides of Trench Excavation shall be vertical unless the S.O. permits otherwise. The Contractor shall be responsible to take the necessary precaution and safety measure to ensure such excavation is safe for working. Stones shall be removed from the trench invert and holes so formed shall be filled with well compacted selected soft granular material. Where mechanical excavators are used, the last 150mm of
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the excavation shall be removed by hand to the required depth, and the trench invert carefully trimmed true to level. Any widening or deepening of Trench Excavations necessary to accommodate curves, joints or bends in the pipe or to provide extra working space for the construction thereof shall be held to be Excess Excavation. Trench Excavation shall wherever practicable be carried out in such a way that every part of the excavation is at least 600mm clear of the existing edge of the carriageway. In any event the Contractor shall take special precautions, which shall include the continuous support of the sides of the excavation, from the time when excavation is begun until the refilling of the trench is placed, to ensure that there is no disturbance of the adjacent road or road foundation. For the purpose of measuring certain work in connection with Trench Excavation "nominal limits" of Trench Excavation are stated above and any excavation outside these limits, which have not been ordered by the S.O. shall be held to be Excess Excavation.
2.14 Trench Excavation in Roads, Road Shoulders and Footpaths All Trench Excavation and other work carried out within the limits of any road reserve shall be completed as rapidly as possible and not more than half of the width of the carriageway shall be obstructed at one time. A minimum width of 4 m wide of traffic lanes shall have to be kept clear for flow of traffic and where necessary the shoulder should be strengthened to the satisfaction of relevant Authorities at the Contractor’s own cost. Road drains and grids shall be kept free from obstruction. Where trenches are excavated in public roads, road shoulders and footpaths of congested areas necessitating carting spoil to distant tips, the Contractor shall employ suitable plant to ensure that the passage of traffic past the Works is not impeded by the loading and unloading of spoil. Excavated materials shall not be left standing on road pavement. All trenches on metalled roads shall not be left open for more than one day and all trenches on road verges shall not be left open for more than three days. Tarmacadam and similar road surfaces shall be broken out neatly along the trench line using a diamond disc road cutter to keep the edges straight and vertical. The Contractor shall take special precautions, including the continuous support of the sides of the excavation from the time excavation is begun until refilling of the trench is completed to ensure that there is no disturbance of the adjacent road or road foundation. The Contractor shall also provide barricades to fence off the works and approved road sign boards placing at regular intervals to ensure safety of the public and vehicles. Special care shall be taken trench excavation for the laying of sewer pipes near or at slope areas to ensure that the existing earth slopes are not disturbed. The length of excavation shall be limited to the length of sewer pipes that can be laid within each work period. Trenches shall be backfilled as soon as possible on completion of pipe laying to avoid leaving them open over extended periods of time, hence compromising the intensity of the slopes.
2.15 Trench Excavation in Fields, etc. The term "fields" includes fields, plantations, padi, grass verges and the like. The Contractor shall have particular regard to the safety of livestock in fields or which may be introduced to the fields, and
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shall ensure that all excavations, access routes and steep or loose slopes arising from the Contractor’s operations in these fields are adequately fenced and protected. After the erection of temporary fencing the Contractor shall remove topsoil to such depth and over such area as may be necessary to provide sufficient material to ensure adequate surface reinstatement of the working areas occupied by the Contractor for construction of the pipeline.
2.16 Rock and Other Materials in Excavations Any material in the excavations which the Contractor considers may be classified as Rock as defined in Section 2.1 shall be notified to the S.O. before commencement of excavation of the material. The quantities of Rock or material alleged to be Rock excavated from within the nominal limits of excavation shall be recorded by the S.O. and the Contractor each day or at such shorter intervals as the S.O. may require. Only such proportion of material so notified, recorded and signed shall qualify for additional payment as Rock. Overbreak (that is excavation outside the nominal limits of excavation) shall be kept to a minimum and shall be held to be Excess Excavation. Materials classified as Grade III or weaker (as defined in Table 10 of BS 5930) shall be classified as ‘Rock’ within the meaning of Section 2.1 only if in the opinion of the S.O.: a)
the material in Bulk Excavation is incapable of being loosened by ripping with a tracked machine, in good working condition and operated by experienced and skilled personnel, of 24 tonne minimum weight and net horse power rating of 240 hp or more, drawing a mounted parallelogram type ripper recommended by the tractor or ripper manufacturer; the ripper shall have a single shank in first class condition with a sharpened cutting point;
b)
the material in Trench Excavation is incapable of being excavated at a rate of 4 cu.m. per hour by hydraulic excavator of minimum net horse power rating of 120 hp, in good working condition and operated by experienced and skilled personnel.
2.17 Supporting Excavation The Contractor shall well and effectively support the sides and ends of all excavations to prevent any fall or run from any portion of the ground outside the excavation and to prevent settlement or damage to structures adjacent to the excavation. Any extra excavation necessary to provide space for such support or other working space shall be held to be Excess Excavation. If, for any reason, any portion of the bottoms, sides or ends of any excavations shall give way the Contractor shall at his own expense take all necessary remedial measures including the excavation and removal of all the ground thereby disturbed both within and beyond the nominal limits of excavation and such extra excavation shall be held to as Excess Excavation. Where the Contractor elects and is permitted by the S.O. to perform excavations with sloping faces (other than sloping excavations shown on the Drawings or required as permanent features of the Works) and without shoring, the excavated faces shall be to stable slopes and heights and the resulting extra excavation shall be held to be Excess Excavation.
2.18 Trimming Excavations
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When excavating to specified levels for the foundation of any structure or pipes or to specified limits for the faces of any structure required to abut against undisturbed ground the Contractor shall not excavate the last 150mm until immediately before commencing the constructional work, except where the S.C. shall permit otherwise. Should the Contractor have excavated to within 150mm above these specified levels or to within 150mm of these specified limits before he is ready or able to commence the constructional work he shall, where required by the S.O., excavate further so as to remove not less than 150mm of material immediately before commencing the constructional work and such further excavation shall be held to be Excess Excavation. Before commencement of any constructional work all shattered and loose material shall be removed from the excavations by hand so as to ensure that the work rests on a solid and perfectly clean foundation or abuts against solid ground.
2.19 Inspection of Excavation When the specified levels or limits of excavation are reached the S.O. shall inspect the ground exposed, and if he considers that any part of the ground is by its nature unsuitable he may direct the Contractor to excavate further. Such further excavation shall be refilled to the specified levels or limits with concrete, selected excavated materials or selected imported material as directed by the S.O. but shall not be held to be Excess Excavation. Should the material forming the bottom of any excavation, while acceptable to the S.O. at the time of his inspection, subsequently become unacceptable to him due to exposure to weather conditions or due to flooding or have become puddled, soft or loose during the progress of the Works, the Contractor shall remove such damaged, softened or loosened material and excavate further by hand to the satisfaction of the S.O. Such excavation shall be held to be Excess Excavation.
2.20 Filling to Embankments and Backfilling to General Excavation Forming Of Embankments And Other Areas Of Fill: (i)
Where embankment is to be constructed against an existing embankment or on existing ground with a cross-slope of 1 vertical to 10 horizontal or steeper the existing ground shall be excavated, irrespective of the type of material (including rock), to form benches with horizontal and vertical surfaces on/against which the embankment will be constructed. The benches shall be contiguous beneath the full width of the embankment and shall be of a width suitable to accommodate construction equipment such as motor graders, trucks, compactors, etc.
(ii)
All earthwork material placed in or below embankments, below formation level in cuttings or elsewhere in the Works shall be deposited and compacted as soon as practicable in layers of thickness appropriate to the compaction plant used. Embankment shall be built up evenly over the full width unless otherwise indicated in the Contract and shall be maintained at all times with adequate camber or slope and surface sufficiently even to enable surface water to drain readily therefrom. During the construction of embankments the Contractor shall control and direct constructional traffic uniformly over their full width. Damage to compacted layers by constructional traffic or water erosion shall be made good by the Contractor at his own expense.
(iii)
Granular fill and free draining material for depositing in water in the areas shown on the Drawings shall conform Clause 2.1 and shall be deposited without the associated use of compaction plant described to the requirements of Clause in Clause 2.21. However,
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subsequent to the completion of filling to the specified levels, the granular fill shall, where specified, be compacted by vibrocompaction. (iv)
Compaction of embankments and other areas of fill shall be undertaken to the requirements of Clause 2.21. The embankment shall be constructed to a sufficient width to permit adequate compaction at the edges before trimming back.
(v)
If the material deposited as fill subsequently reaches a condition such that it cannot be compacted in accordance with the requirements of the Contract the Contractor shall at his own expense, either :(a)
make good by removing the material off the embankment either to tip or elsewhere until it is in a suitable physical condition for reuse, and replacing it with suitable material; or
(b)
make good the material by mechanical or chemical means; or
(c)
cease work on the material until its physical condition is again such that it can be compacted as described in the Contract.
(vi)
Isolated boulders each within the range 0.2m3 to 0.1m3 in size may be incorporated in earth embankments at the discretion of the S.O. provided that the specified compaction requirements are met. No stone exceeding 0.02m3 shall be placed less than 0.5m below formation level of carriageway or hard shoulders.
(vii)
Work on embankments and/or cuttings in areas required for the construction of bridges and other structures shall not be carried out until the S.O. agrees that construction of such structures is sufficiently advanced such that there is no risk of interference or damage to them. However, where piling for a structure is required through the embankment, the embankment shall be built up to a level not less than the elevation of the soffit of the pile cap or to conform to Clause 2.38 in the case of soft ground prior to any piling.
The Contractor shall arrange the timing and rate of placing fill material around or upon any completed or partially completed structure in such a way that no part of the Works is over-stressed, weakened, damaged or endangered. All fill materials adjacent to complete structures shall be so placed as to maintain adequate drainage and to prevent accumulation of water. In particular, the placing of fill materials around the walls of basements, and tanks shall commence only after the walls and floor have been completed and have attained their full specified strength. Fill around the walls of reservoirs shall not commence until after satisfactory completion of testing. Fill material behind walls fixed at the top to the roof shall not be placed until the roof has been completed and if made of concrete, has attained its full specified strength and had the temporary supports removed. The materials shall be placed so as to exert a uniform pressure around the walls of a structure, and each layer shall be placed with a fall to prevent the accumulation of water. The Contractor shall when placing the filling or backfilling make due allowance for any settlement that may occur before the end of the Defects Liability Period. Where necessary, the Contractor shall at the end of the Defects Liability Period remove any excess material or make up any deficiency of backfilling or filling to the specified levels.
2.21 Compaction of Embankments and Other Areas of Fill
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(i)
All materials used in embankments and as fill elsewhere shall be compacted as soon as practicable after deposition. Unless otherwise stated on the Drawings, suitable materials shall be laid in layers not greater than 300mm loose depth and shall be compacted with appropriate compaction equipment. Compaction of each layer shall only be undertaken when at least 75% of the samples taken at a rate of one sample per 500m2 for a length not exceeding 100m show a moisture content within the limits of optimum moisture content + 3% as determined in accordance with BS. 1377, Test 13. The fill shall be processed by scarifying, grading, mixing, wetting, aerating, drying or other approved method so that the material is brought within the above designated limits.
(ii)
The Contractor shall submit to the S.O. for approval his proposals for the compacting of each main type of material to be used in the embankments. These shall include proposals for the number of passes in relation to the loose depth and the type of plant for each material. The Contractor shall carry out compaction trials, supplemented by any necessary laboratory investigations, as required by the S.O., using the procedures proposed by the Contractor for the earthworks and shall satisfy the S.O. that all the specified requirements regarding compaction can be achieved. Compaction trials with the main types of material likely to be encountered shall be completed before any permanent work using any of these materials will be allowed to commence.
(iii)
Filter material shall be compacted in layers not exceeding 150mm by passes of a smoothwheeled vibrating roller. One pass shall consist of as many journeys of the roller as shall ensure that the bearing width of the roller completely covers the layer once. An overlap of 450mm between the adjacent paths of the roller shall be maintained. All filter materials shown on the Drawings as vertical layers or layers whose surface is inclined at a slope steeper than one horizontal to three vertical shall be described as filter material in vertical layers. The Contractor shall ensure that the filter material so placed will comply with the specified requirements.
(iv)
Earthmoving plant shall not be accepted as compaction equipment under this Clause.
(v)
The requirements for compaction of embankment fill are as follows and shall apply equally to all clayey, silty, sandy or gravelly materials placed in the embankment.
(vi)
The Contractor shall ensure that the embankment and other areas of fill are compacted to 95% of maximum dry density for the 900mm below formation and 90% of maximum dry density elsewhere. The maximum dry density shall be determined in accordance with BS 1377, Test 13. The Contractor shall demonstrate compliance with Clause 2.21 (v) for material within 900mm of formation by carrying out field density tests in accordance with BS 1377, Test 15 at a rate of not less than one test per 2,000 cubic metres.
(vii)
The S.O. may at any time order or carry out field density tests on material which he considers has been inadequately compacted. If the test results confirm this to be the case then the Contractor shall carry out such further work as the S.O. may approve to comply with the requirements of the Contract.
(viii)
Without prejudice to the relevant Clause in the Jabatan Kerja Raya Conditions of Contract and in order that the S.O. may make proper provision for the supervision and testing of compaction in the permanent work, the Contractor shall, not less than 24 hours before he
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proposes to carry out earthwork compaction during periods of overtime, apply in writing to the S.O. for permission to do so.
2.22 Earthworks to be Kept Free of Water (i)
The Contractor shall arrange for the rapid dispersal of water shed on to the earthwork or completed formation during construction, or which enters the earthwork from any source, and when practicable the water shall be discharged into the permanent outfall for the pipe drainage system. The Contractor shall provide adequate means of trapping silt in temporary systems discharging into permanent drainage systems. The arrangements shall be made in respect of all earthwork including excavation whether for pipe trenches, foundations or cuttings.
(ii)
The Contractor shall provide, where necessary, temporary watercourses, ditches, drains, pumping or other means of maintaining the earthwork free from water. Such provision shall include carrying out the work of forming the cuttings and embankments in such a manner that their surfaces have at all times a sufficient minimum crossfall and, where practicable, a sufficient longitudinal gradient to enable them to shed water and prevent ponding.
(iii)
In pumping out excavations and in any lowering of the water table the Contractor shall pay due regard to the stability of all structures.
2.23 Embankments on Soft Soil (i)
The construction of embankments on soft soil shall be carried out in accordance with the methods, sequence, and rates of filling indicated on the Drawings and other sections of the Specification. In each case the method of construction shall be reflected in the Contractor’s programme submitted with the tender, and in the subsequent work’s programme.
(ii)
The compaction of all embankment material including any portion placed to make up anticipated settlements shall be in accordance with the requirements of Clause 2.21.
(iii)
During the construction of embankments on soft soil, the Contractor shall carefully monitor pore water pressures, settlements and horizontal displacements of the embankment material as indicated by the piezometers, rod settlement gauges and displacement markers.
(iv)
Unless otherwise instructed by the S.O. such readings shall be taken twice weekly during filling operations and weekly during rest periods. Plotted records shall be submitted, in a format agreed with the S.O., within 24 hours of the readings being taken. For the computation of the volume of fill that has settled below the original level of the ground on which the embankment is constructed, the measured settlement of each marker shall be used for the purpose following the method shown on the Drawings.
(v)
Should the S.O. so direct, filling operations shall be immediately suspended and shall not resume until directed by the S.O.
(vi)
Drainage Layer When shown on the Drawings or as directed by the S.O., Geotextile complying with the requirements of Clause 10.5 shall be placed on the cleared and graded subsoil foundation
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prior to the deposition of free draining material as defined in Clause 2.1 of the Specifications. Free draining material shall be deposited without the associated use of compaction plant to the thickness shown on the Drawings. No construction plant shall travel directly over the geotextile layer until a sufficient thickness of material has been placed to prevent damage to the geotextile or to avoid heave of the foundation soil. A second layer of geotextile shall be laid on top of the free draining material before commencement of deposition of embankment fill.
2.24 Trenches Not to be Left Open No length of trench excavation shall be started until the materials to be laid in that length are available on Site. Trench Excavation shall be carried out expeditiously and, subject to any specific requirements of the Contract, the refilling and surface reinstatement of Trench Excavation shall be commenced and completed as soon as reasonably practicable after the materials have been laid. Joint holes for pipeworks may be left unrefilled until the joints have been air tested and moulded or protected. The Contractor shall furnish, install and operate all necessary machinery, appliances, and equipment to keep the excavation sufficiently free from the water during construction of the work to permit proper laying and jointing, and shall dispose of water so as not to cause nuisance, injury to persons or damage to public or private property. Particular care shall be exercised when carrying out dewatering activities adjacent to existing structures or slopes to ensure that no damage is caused. Pipelaying shall follow closely upon the progress of Trench Excavation, and the Contractor shall not permit the carrying out of Trench Excavation in unreasonably excessive lengths until pipelaying matches up with the progress of Trench Excavation. The Contractor shall take precautions to prevent flotation of pipes in locations where Trench Excavations may be flooded and these precautions may include the partial refilling of the trench leaving pipe joints exposed while awaiting tests of the joints. If the S.O. considers that the Contractor is not complying with any of the foregoing requirements he may prohibit further Trench Excavation until he is satisfied with the progress of laying and refilling of Trench Excavation.
2.25 Refilling Trench Excavation Trench Excavation shall normally be refilled using suitable materials selected from excavations or imported fill materials. Excavated material for trench refilling shall be soft granular material free from stones of all kinds to be deposited in 150mm layers and thoroughly rammed under and around the pipe with suitably shaped rammers working alternately on either side of the pipe (particular care being taken to avoid damage to the pipe and any sheathing) until the trench has been refilled up to the swell of the pipe, and thereafter until the soft filling has been carried up at least 300mm above the top of the pipe. The soft filling however shall not be muddled or unsuitable material. The remainder of the refilling may consist of coarse material free from boulders and clods of earth larger than 150mm in size provided that the compacted refill is, in the opinion of the S.O., sufficiently dense to prevent material from the superimposed layers being washed into the voids in such refill.
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This coarse material shall be spread in layers of depth not greater than 225mm and be thoroughly rammed by an approved mechanical rammer or pan vibrator. The coarse filling shall be carried up to the level at which surface reinstatement is to commence or to such level at which the surface reinstatement of the whole of the topsoil, will leave the finished work sufficiently "proud" to allow for future settlement to the original ground level. The reinstated surface shall be rolled with a two-tonne roller when the material is dried. Any part of the reinstated surface that settled beyond the adjacent original ground level the Contractor shall have to make good of the settlement to avoid formation of drains or gullies within the refilled trenches. Sand material for trench excavation backfilling shall be deposited in 150mm layers on both sides of the pipe simultaneously and thoroughly compacted and around the pipe working alternately on either side of the pipe unless shown otherwise in the Drawing, until the trench has been filled up to 150mm above the top of the pipe unless shown otherwise in the Drawing except for pipes laid in roads where the sand backfill shall be brought up to the base course formation level. The sand filling material shall be compacted either by a suitable mechanical vibrator and/or by an approved system of water jet. The topping of the refilling shall be in accordance with the remainder of the refilling for trench excavation as described above for backfill with excavated material. Sand (Class X) filling materials falling within the grading limits as shown in Appendix 2.1 shall be accepted for use. Quarry dust shall not be considered for use as filling material. Where necessary the Contractor shall adjust the moisture content of the refill material, as determined in accordance with BS 1377 Test 13, either by drying out or by adding water to assist the compaction of the material. Should the material to be placed as refilling, while acceptable at the time when approved, become unacceptable to the S.O. due to exposure to weather conditions or due to flood or have become muddled, soft or segregated during the progress of the Works, the Contractor shall not use such material for refilling trenches and shall only use fresh material approved by the S.O. Compaction of trench refilling shall be undertaken to the requirements of Section 2.21. In particular, the Contractor shall demonstrate that the compaction is to 95% of maximum dry density by carrying out field density testing in accordance with BS 1377 Test 15. Trench Excavations shall be refilled with concrete to the heights and limits as shown on the Drawings and where directed by the S.O.
2.26 Spoil Tips on the Site The limits and finished levels of spoil tips shall be as shown in the Drawings or as directed by the S.O. Spoil tips may be used to store excavated material as required and shall be arranged by the Contractor subject to the S.O.’s approval having regard to any particular requirements of the Contract. Only material which is approved by the S.O. shall be placed in the spoil tips, topsoil being placed in separate spoil tips where so ordered. No tree trunks, stumps, roots, branches or rubbish of any kind shall be placed in spoil tips. The spoil tips shall be so shaped as to maintain stability and good drainage at all times.
2.27 Treatment of Material from Excavation
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Subject to any specific requirements of the Contract, the Contractor shall make his own arrangements for the temporary storage of any excavated material which is required for use in refilling Trench Excavation, and backfilling to general excavation including any necessary double handling. In this connection the Contractor shall have regard to the working areas available to him for the construction of the Works. Any temporary tips alongside the excavations shall be to stable slopes and heights. Where the nature of the excavated material is suitable the Contractor’s temporary storage as aforesaid shall include for the separate storage as the S.O. may direct of any of the various grades of material hereinafter specified for the refilling and surface reinstatement of excavations, namely, soft granular material, coarse granular material, hard material and topsoil. The Contractor shall ensure that no excavated material which is suitable and is required for re-use in the Works is disposed off outside Site, unless it is surplus for use in the Works. Any excavated material not required or not suitable for use in the Works shall become the liability of the Contractor and he shall be entirely responsible for its removal from the Site and for its ultimate disposal. The Contractor shall comply with all the regulations for the disposal of surplus excavated materials off the site including the payment of royalties, fees, etc, which may be imposed by the relevant Authorities.
2.28 Surface Reinstatement in Road Verges, Fields, etc. Where Trench Excavation is in road verges, fields and grassed areas, the turf previously removed will suffice for surface reinstatement providing that the grass has not been killed during stacking and that the surface is free from all loose stones. After refilling Trench Excavation as specified, the Contractor shall replace all topsoil previously removed and it shall be evenly distributed and levelled over the full extent of the stripped area. The working space occupied by the Contractor which was originally covered with grass if destroyed during the course of construction shall be covered with 75mm of topsoil, close turfed and maintained until the new grass is properly established at the Contractor’s expense. Other areas not originally covered with grass shall be restored to their former state. Road verges shall be restored to their original width and to a minimum fall of 1 in 24 away from the road and towards the ditch (if any). Restoration of the dip shall be carried out unless the fact that no dip existed prior to excavation has been recorded in writing and agreed to by the S.O. The Contractor shall restore all surfaces in a condition not inferior to that which existed prior to commencement of works. Any damage to the metalled road due to excavation work alongside road verges or shoulders shall be reinstated to the satisfaction of the S.O. and the Authorities concerned at no extra cost to the Employer.
2.29 Works in Roads and Road Reserves Where work is carried out within road reserve, the Contractor shall comply fully with all regulations and requirements in force in that place by all relevant local and public Authorities.
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The times of working allowed by the Authorities may or may not fall within day light hours or within the normal working hours of the Authorities. The Authorities may impose charges for works carried out on road verges and metalled roads and the Contractor shall pay the Authorities and recover the cost under the appropriate items in the Bill of Quantities.
2.30 Surface Reinstatement in Roads and Footpaths Surface reinstatement of roads and footpaths shall be restored to the approval of the S.O. and to the requirements of the Authorities concerned or the party concerned. Any settlement or defects prior to final surface reinstatement shall be made good by the Contractor to the satisfaction of the S.O. Where the pipe trench crosses or is along tarmacadam roads and footpaths belonging to private owners or Authorities, the pipe shall be surrounded with sand and topped up with 375mm thick of crusher run material followed by 100mm thick of dense bituminous mix comprising 60mm thick binder course and 40mm thick wearing course unless otherwise specified or shown in the drawings. The compacted crusher run and binder course surfaces shall receive a layer of prime coat and tack coat respectively before the application of binder course material and wearing course materials. All fill materials shall be compacted by approved means. The consolidated surface shall be brought up to the same level of the adjoining road. Any subsidence shall be filled in by the Contractor using the same materials. The road shall be kept continuously at its proper level to the satisfaction of the S.O. and the Authorities from the date of filling in the trench until the surface is finally restored. All materials for this reinstatement and subsequent maintenance shall be supplied by the Contractor. When any section has been reinstated as specified the Contractor shall notify the S.O. who in the presence of the Contractor shall inspect the length of reinstated trench. The S.O. shall at this inspection indicate any further reinstatement required and the Contractor shall complete this work to the satisfaction of the S.O. and the Authorities concerned within fourteen days of the inspection. Acceptance of reinstatement by the S.O. or the Authorities at this inspection shall not relieve the Contractor of his responsibility for the maintenance of surfaces as specified above.
2.31 Other Structures in the Pipeline The Contractor shall carry out further excavation as may be necessary to accommodate structures such as thrust blocks and valve chambers. Such excavation shall include for disposal of surplus material and, where appropriate, for backfilling round the structures.
2.32 Land Drains Where land drains, mole drains or field drains are severed by Trench Excavation they shall be kept in effective temporary operation during construction. The Contractor shall submit to the S.O. for approval a temporary drainage arrangement to ensure the water course is not hindered during the construction. The drain on either side of the Trench Excavation shall be cut-back for at least 300mm and temporary pipes of suitable length and diameter shall be joined to the existing drain and laid resting with the ends on solid ground with suitable stopping to prevent the subsequent run of land drainage water into
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the trench. During trench re-filling, the refill material shall be carefully placed and thoroughly compacted under the temporary pipes to give them adequate support. Should any existing sub-soil or field drains be uncovered during general excavation, the Contractor shall either carefully replace them when backfilling, or if this is impracticable shall divert them to new drains or ditches, or otherwise relay them as the S.O. may direct. At the appropriate stage of refilling the Trench Excavation the drains shall be permanently restored to the satisfaction of the S.O.
2.33 Care of Existing Services Information relating to the positions of all existing mains, cables, culverts, pipes, drains or services of any kind shall be ascertained by the Contractor. Notwithstanding any information which may be furnished by the Employer or the S.O., the Contractor shall be responsible for ascertaining the positions of all utilities including all mains, pipes and cables whether underground or overhead, within or near the Site by pilot trenching, radio detection, including using current detectors, ultrasonic detectors, metal detectors, etc and from his own inspection of the site and from the respective utility authorities and other public authorities. Where services are shown on the drawings or where there is evidence of services in the ground, the Contractor shall also determine their exact positions. In addition the Contractor shall watch for and determine the position of any service which may not have been marked. Where Trench Excavation is carried out close to or across the line of sewers, pipes, cables and other services the Contractor shall provide temporary adequate supports to secure the services and where such sewer, pipe, cable or other service is temporarily displaced or disturbed it shall be restored to its original state. If restoration of any service to its original state cannot be achieved then it shall be replaced and made good. The cost of excavating around any service which crosses the trench, and of temporarily supporting it while pipelaying is undertaken, shall be deemed to be included in the rates for excavation. All damage to services shall be made good to the satisfaction of the S.O. and the Authorities concerned. The cost of making good any damage shall be deemed to be included in the rates for excavation. In the event that any damaged service shall only be repaired by the Authority concerned, all costs whatsoever relating to the repairing of the damaged service undertaken by the Authority shall be at the Contractor’s expense. Where damage to a service had already existed prior to excavation or other work, repair of the damaged service shall be undertaken by the Contractor, if so ordered by the S.O. and the Contractor shall be paid on Daywork for repairing such service. Where in the opinion of the S.O., construction of the pipeline cannot reasonably be carried out unless the sewer, pipe, cable or other service is permanently severed or permanently diverted or permanently supported the Contractor shall undertake such work if so ordered by the S.O. Any such work if carried out shall be to the satisfaction of the S.O. and of the Authority concerned and shall be paid for at Daywork where necessary and at the appropriate Contract Rates. Where pipes are laid under culverts they shall, subject to other provisions in the Contract and to the S.O.’s instructions, be given a concrete surround extending for 600mm clear on each side of the culvert, and a concrete half haunch to the culvert shall be provided over the width of the trench cast directly on top of the concrete surround. The cost of all work in removing any piles and concrete bed under culverts and of temporarily supporting the culvert during pipelaying shall be deemed to be covered by the rates for the items in the Bill of Quantities for pipes crossing under culverts.
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2.34 Hedges, Fences and Walls Where the Trench Excavation passes under barriers such as hedges, fences and walls the Contractor shall, as a temporary measure during construction, provide temporary fencing for any parts of such barriers that have been removed. After trenches have been refilled and surfaces reinstated, the Contractor shall carry out work as the S.O. may order for permanent restoration of such barriers. In the case of a hedge the section removed shall be replaced by new plants of the appropriate variety and where ordered by the S.O. the plants shall be protected from livestock on both sides by an adequate post and barbed wire fence. During the Defects Liability Period all hedges replanted in the above manner shall be inspected and any dead plant replaced by the Contractor to the satisfaction of the S.O.
2.35 Crossing Watercourses, etc Where the pipeline crosses underneath rivers culverts and other watercourses the Contractor shall be deemed to have allowed for all the additional measures necessary for the proper construction of the pipeline including maintaining the full flow of water.
2.36 Top Soiling Topsoil shall be evenly spread and trimmed over embankments and other areas to the slopes and levels shown on the Drawings or ordered by the S.O. The depth after spreading and trimming shall be 75mm unless otherwise directed, measured normal to the surface. All clods and lumps shall be broken up and any rubbish, stones, roots and weeds shall be removed.
2.37 Turfing The Contractor shall establish grass by continuous conventional turfing or by hydroseeding as directed. Conventional (closed) Turfing Prior to conventional (Closed) turfing an approved pre-turfing fertiliser with N:P:K of 10:15:10 shall be worked into the top 50mm of the topsoil at the rate recommended by the manufacturer. The areas thus prepared shall be close turfed and lightly beaten to a well-bonded pattern with no gaps in between the turfs. Where turf is laid on slopes steeper than 1 on 3, each turf shall be securely pegged down with two cleft wooden pegs 150mm long. All turfed areas shall be lightly rolled with an approved roller immediately after laying, and shall be watered regularly with addition of fertilisers until the grass has been established. Grass areas affected by trench excavation shall be restored as specified above. Spot Turfing
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Alternatively where indicated on the Drawings, the areas shall be spot turfed with each turf approximately 200mm by 200mm by 50mm thick and the distance between the centre lines of divots in the form of a triangular pattern shall not exceed 500mm. Turf shall be laid immediately after delivery to Site. Hydroseeding Seeding or hydroseeding shall be carried out as soon as practicable on slopes and other areas as shown on the Drawings and/or directed by the S.O. The Contractor shall submit to the S.O. for his consideration and approval, at least (4) weeks in advance of the proposed work, full details of his proposed method of seeding or hydroseeding. The information submitted shall include, but not necessarily be limited to, a full description of the following aspects of the work: i.
the preparation of the areas to be seeded or hydroseeded, including if appropriate the amount of topsoil to be used and its method of application;
ii.
the details and results of investigations to determine which types of grass and legume are compatible with the soil in the areas to be seeded;
iii.
the types of grass and legume (if any) and strains of seed to be used, and the function, root and growth characteristics of each type;
iv.
the rates of application of the grass and legume seeds;
v.
the composition of fertiliser to be used at the time of seeding, and its rate of application;
vi.
the composition of fertiliser to be used after seeding, the times of application after seeding, and the rates of application;
vii.
the type of mulch to be used and its method and rate application;
viii.
the amounts of lime or other chemicals (if any) to be applied to improve the soil before, during and/or after seeding;
ix.
the type and amounts of binding agent to be applied with the seeds, mulch fertiliser, etc., as appropriate;
x.
the proportions and methods of preparation of the seeding mix;
xi.
the equipment and methods to be used in preparing and placing the seeding mix and other materials;
xii.
the cultivation and after-care of the seeded areas, including rates and frequencies of watering, fertilising, grass cutting and general maintenance for at least 1 year after seeding;
xiii.
the time after seeding required for establishing permanent, dense growth of grasses, which will require minimal maintenance; and
xiv.
guarantees of success of seeding work.
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Grass Maintenance All grass shall be regularly watered until the vegetation is satisfactory established to the satisfaction of the S.O. Any dead grass be replaced at the Contractor’s own expense. The Contractor shall be responsible to maintain the turfed area in good conditions by cutting, trimming and weeding at monthly intervals until the end of the Defects Liability Period. Where turf fails to establish itself, the Contractor shall grass the effected area again at no extra cost to the Employer until the grass establishes itself and thereafter the monthly maintenance aforesaid shall be continued.
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Appendix - 2.1
GRADATION CURVES FOR FILTERS, AND RIP-RAP MATERIALS FOR GENERAL FILLING
GRADATION CURVES FOR CRUSHER RUN
Civil Work Specifications Final Document (June 2008)
App2-1
Section 3 - Concrete
3.0
CONCRETE
3-1
3.1
Scope
3-1
3.2
Concrete Production at the Site
3-1
3.3
Test Certificates
3-1
3.4
Aggregate Samples
3-1
3.5
Records of Concreting
3-1
3.6
Concrete Mixes – Submission of Design
3-2
3.7
Construction Joints and Lifts – Joints Layout and Formwork Lines for Concrete Placing
3-2
3.8
Cement
3-2
3.9
Storage of Cement
3-3
3.10 Aggregates
3-3
3.11 Storage of Aggregates
3-4
3.12 Water
3-4
3.13 Admixtures
3-4
3.14 Test Equipment
3-5
3.15 Grades of Concrete
3-6
3.16 Free Water/Cement Ratio
3-6
3.17 Limits of Salt Content
3-6
3.18 Workability
3-7
3.19 Design of Concrete Mixes
3-7
3.20 Trial Mixes
3-8
3.21 Material Batching
3-9
3.22 Mixing Concrete
3-10
3.23 Ready-mixed Concrete
3-10
3.24 High Alumina Cement
3-10
3.25 Preparing for Concreting
3-11
3.26 Transporting Concrete
3-11
3.27 Placing concrete
3-11
3.28 Concreting in Hot Weather
3-11
3.29 Compaction
3-12
3.30 Attendance of Steel Fixer and Carpenter
3-12
3.31 Curing of Concrete
3-12
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3.32 Construction Joints
3-13
3.33 Dimensions and Surfaces of Finished Concrete
3-13
3.34 Unformed Surfaces
3-14
3.35 Built in Pipes and Plant
3-15
3.36 Structural Precast Concrete
3-15
3.37 Installation of Precast Concrete Units
3-16
3.38 Prestressed Concrete
3-17
3.39 Precast Concrete Products
3-17
3.40 Sampling and Testing of Aggregate
3-18
3.41 Quality Control: Sampling and Testing of Concrete
3-18
3.42 Compliance with Specified Requirements
3-18
3.43 Non-Compliance
3-19
3.44 Cutting and Testing of Core Samples
3-19
3.45 Inspection Procedures
3-19
3.46 Concrete Protection Systems
3-20
3.47 Concrete Protection Procedures
3-22
3.48 Machinery Bases and Grouting In
3-22
3.49 Epoxy Protective Coating for Concrete Surfaces
3-23
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3.0 Concrete 3.1
Scope
This section covers the supply of materials for concrete, design of concrete mixes, mixing, transporting, placing and curing of concrete, testing of concrete and quality control of concrete.
3.2
Concrete Production at the Site
At the commencement of the Contract the Contractor shall submit for the approval of the S.O. a method statement detailing with regard to the requirements of this Specification his proposals for the organisation of concreting activities at the Site. The method statement shall include the following items: (a) (b) (c) (d) (e)
plant proposed; layout of concrete production facility; proposed method of organisation of the concrete production facility; quality control procedures for concrete and concrete materials; method of transport and placing of concrete;
3.3
Test Certificates
Unless otherwise directed by the S.O., manufacturer's test sheets shall be supplied with each consignment of cement and admixture certifying compliance with the relevant standard. The Contractor shall also submit to the S.O. certificates of calibration for the weighing and dispensing equipment on the concrete batch mixing plant, certified test results for all tests carried out on aggregate, water, fresh concrete and hardened concrete, all as specified.
3.4
Aggregate Samples
Prior to the commencement of the trial mixes of concrete the Contractor shall submit for approval samples 50kg in weight of each aggregate which he proposes to use. The source of each aggregate shall be clearly marked on the container of each sample. Certified test results demonstrating compliance with the relevant quality standard shall be submitted at the same time. Samples approved by the S.O. shall remain preserved at Site for reference.
3.5
Records of Concreting
An accurate and up to date record showing dates, times, weather and temperature conditions when various sections of the Works are concreted shall be kept by the Contractor and shall be available for inspection by the S.O. The Contractor shall also record the results of all tests of concrete and shall identify these results with the parts of the Works of which the sampled material is representative.
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For each grade of concrete, the Contractor shall submit to the S.O., not later than twenty-four hours after concreting, a daily return of the number of batches mixed, the number of batches and total volume of concrete placed, the number of batches wasted or rejected and the weight of cement used. The return shall also include specific details of each location in the Works where concrete is placed, together with the grade of concrete, total volume of concrete placed and the number of batches used for each location.
3.6
Concrete Mixes – Submission of Design
At the commencement of the Works the Contractor shall design a mix for each grade of concrete which will be required for use in the Works and shall submit full details of the mix designs to the S.O. for his approval. Each mix design shall be according to the requirements of BS 5328.
3.7
Construction Joints and Lifts – Joints Layout and Formwork Lines for Concrete Placing
The Contractor shall submit to the S.O. for his approval, as soon as is practicable after the acceptance of his tender and not less than three weeks before the commencement of concreting, drawings showing his proposals for placing concrete on which the position of all construction joints and lifts shall be shown. No concreting shall be started until the S.O. has approved the method of placing, the positions and form of the construction joints and the lifts. The construction joints shall be located so as not to impair the strength of the structure. Rebates, keys or notches shall be formed and waterstops inserted as the S.O. may require. The position of construction joints and the size of formwork panels shall be so co-ordinated that where possible the line of any construction joint coincides with the line of a formwork joint and that in any case all construction joint lines and formwork joint lines appear as a regular and uniform series. For all exposed horizontal joints and purposely inclined joints, a uniform joint shall be formed with a batten of approved dimensions to give a straight and neat joint line.
3.8
Cement
The cement used for any particular mix shall comply with whichever of the following standards is relevant:a. b. c. d. e. f.
Ordinary and Rapid-hardening Portland cement Sulphate resisting cement Portland Blastfurnace cement High Slag Blastfurnace cement Portland Polverished-Fuel Ash cement High Alumina cement
BS EN 197-1 BS 4027 BS EN 197-4 BS 4246 BS EN 197-1 BS 4550-6 & BS 14647
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General: In addition to the requirements for soundness of cement given in the relevant British Standard for the type of cement being used, the cement shall also be tested for soundness in accordance with ASTM C151-77 'Standard Test Method for Autoclave Expansion of Portland Cement'. The expansion of the cement bar resulting from this test shall not exceed 0.8 %. The Contractor shall provide from each consignment of cement delivered to the Site such samples as the S.O. may require for testing. Any cement which is, in the opinion of the S.O., lumpy and partially set shall be rejected and the Contractor shall promptly remove such cement from the Site. Cement which has been stored on the Site for more than forty days and cement which in the opinion of the S.O. is of doubtful quality shall not be used in the Works unless it is retested and the test results show that it complies in all respects with the relevant standard. All concrete shall be produced with cement that is resistant to attack by chlorides and sulphates, durable in a high humidity environment and not subject to alkali silica reaction. The cement to be used throughout the works shall be Portland Blastfurnace Cement or equivalent complying with MS 1389:1995 (BS EN 197-4:2004). The cement shall be produced by blending with Ordinary Portland Cement conforming to BS EN 107-1 and Ground Granulated Blastfurnace Slag (GGBS) conforming to BS EN 15167 (MS 1387:1995). The blend shall contain not less than 36% GGBS and not more than 65% GGBS by mass of combination.
3.9
Storage of Cement
Immediately upon arrival at the Site, cement shall be stored in silos designed for the purpose or in dry weather-tight and properly ventilated structures with floors raised 500mm above ground level with adequate provision to prevent absorption of moisture. All storage facilities shall be subject to approval by the S.O. and shall be such as to permit easy access for inspection and identification. Each consignment of cement shall be kept separately and the Contractor shall use the consignments in the order in which they are received. Cement of different types and from different sources shall be kept in clearly marked separate storage facilities. Cement delivered to the Site in drums or bags provided by the supplier or manufacturer shall be stored in the unopened drums or bags until used in the Works. Any cement in drums or bags which have been opened on the Site shall be used immediately or shall be disposed off.
3.10 Aggregates Aggregates for concrete shall be obtained from an approved source and shall conform with the requirements of BS EN 12620. Sampling and testing of aggregates shall be carried out as required by the S.O. in accordance with the requirements of the appropriate clauses of BS 81 Water absorption of aggregates when tested in accordance with the standard procedure prescribed in Part 2 of BS 812, shall not exceed 3%. The aggregates to be supplied shall not give rise to any alkali reaction with the cement, whether silica or carbonate. Potential reactivity or otherwise of aggregates shall be determined in accordance with ASTM C 289.
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In addition, the soluble chlorides and sulphates content of the aggregates shall be such that the concrete mix as a whole complies with the specified limits of salt content. Tests for chlorides and sulphates and for potential alkali reaction shall be carried out when required by the S.O. Notwithstanding any provisions contained herein, limestone aggregates shall not be used in underground and water retaining structures.
3.11 Storage of Aggregates The Contractor shall provide means of storing the aggregates at each point where concrete is made such that: (i) (ii) (iii)
Each nominal size of coarse aggregate and fine aggregate shall be kept separated at all times; Contamination of the aggregates by the ground or other foreign matter shall be effectively prevented at all times; Each heap of aggregate shall be capable of draining freely.
The Contractor shall ensure that graded coarse aggregates are tipped, stored and removed from store in a manner that does not cause segregation. Wet fine aggregate shall not be used until, in the opinion of the S.O., it has drained to a constant and uniform moisture content, unless the Contractor measures the moisture content of the fine aggregate continuously and adjusts the amounts of fine aggregate and added water in each batch of concrete mixed to allow for the water contained in the fine aggregate. If necessary to meet the requirements of this clause, the Contractor shall protect the heaps of fine aggregate against inclement weather.
3.12 Water Water for washing aggregates and for mixing concrete and curing shall be clean and free from harmful matter and shall satisfy the recommendations to BS EN 1008. When required by the S.O. the Contractor shall take samples of the water being used or which it is proposed to use for mixing concrete and test them for quality, including determining the concentration of sulphates and chlorides, which shall be such that the concrete mix as a whole complies with the specified limit for salt content.
3.13 Admixtures Admixtures shall mean material added to the concrete materials during mixing for the purpose of altering the properties of the concrete mix. Admixtures containing calcium chloride shall not be used. Admixtures shall not be used unless the S.O. has given his prior approval in writing for each instance. Both the amount added and the method of use shall be to the approval of the S.O. who shall also be provided with the following information: (i)
the typical amount added and the detrimental effects if any, due to an increase or decrease in this amount;
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(ii)
the chemical name(s) of the main active ingredient(s) in the admixture;
(iii)
whether or not the admixture leads to the entrainment of air when used at the amount the manufacturer recommends.
Any approved admixture shall conform to whichever of the following standards is appropriate:-
air entraining admixtures BS EN 934-6 water reducing admixtures BS EN 934-6 retarding admixtures BS EN 934-6 fly ash and raw or calcined natural pozzolans for use as a mineral admixture ASTM C 618
When more than one admixture is used in a concrete mix the compatibility of the various admixtures shall be ascertained by standard tests and certified by the manufacturers. Admixtures shall be used in accordance with the manufacturer's instructions.
3.14 Test Equipment The Contractor shall furnish all equipment and materials necessary for collecting samples and carrying out field laboratory tests on materials for concrete and on fresh and hardened concrete. Laboratory equipment shall be housed in a suitable laboratory building on the Site, which shall also incorporate space for storage of field test equipment and for curing of concrete test cubes in an orderly manner so that they are readily accessible for testing on the due date. The Contractor shall also furnish all weights, containers and other equipment necessary for testing the weigh-batching equipment for concrete materials and the dispensers for admixtures.
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3.15 Grades of Concrete Grades of concrete for use in the Work shall be as shown in the table below: Concrete Grade
Maximum aggregate size (mm)
C50/20 C40/20 *C35A/20 *C35A/40 C30/20 C25/20 C20/20 # C15/20
20 20 20 40 20 20 20 20
Characteristic strength at 28 days (N/sq.mm) 50 40 35 35 30 25 20 15
Minimum Cement content (kg/cu.m) 410 410 370 350 350 330 250 225
Maximum free Water/cement ratio 0.45 0.45 0.50 0.50 0.50 0.55 0.60 0.65
Note : * All water retaining structures shall use Grade C35A concrete. Grade C35A/40 is recommended for thick section. # Only for blinding purpose Concrete grade is that number which represents its 28 day characteristic strength expressed in N/sq.mm. Characteristic strength is that value of cube crushing strength below which none of all test results fail. This condition shall be deemed to be satisfied when test results comply with the specified test requirements. Maximum free water/cement ratios shall be based on aggregates being in a surface-dry condition.
3.16 Free Water/Cement Ratio In designing and establishing approved mixes of concrete for any part of the Works the Contractor shall keep strictly within the limitations on free water/cement ratios which may be shown on the Drawings or expressly stated elsewhere as applying to concrete for particular parts of the Works.
3.17 Limits of Salt Content No concrete shall contain more than the following total quantities of substances expressed as percentages by weight of cement: (a)
For mixes containing ordinary Portland cement to BS EN 197: Total water soluble chlorides 0.4% (as chloride ions)
(b)
For mixes containing cements complying with BS 4027: Total chlorides 0.2% (as chloride ions)
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(c)
For mixes used for prestressed concrete (all cement types): Total chlorides 0.1% (as chloride ions)
(d)
For all mixes: Total acid soluble sulphates
4.0% (as SO3 ions)
Tests shall be carried out in accordance with the following standards: -
chlorides in aggregates sulphates in aggregates chloride ion in mixing water sulphates in mixing water
ASTM D 1411 BS 1377 Test 9 ASTM D 512 ASTM D 516
3.18 Workability The workability of each grade of concrete shall be such that satisfactory compaction can be obtained when the concrete is placed and vibrated and that there is no tendency to segregate when it is handled, transported and compacted by the methods which the Contractor proposes to use in the Works. For reinforced concrete, the compacting factor, determined by the method described in BS 1881, shall not be less than 0.85 nor greater than 0.9. For unreinforced concrete the compacting factor shall be not greater than 0.85. Where pumping of concrete is permitted, the compacting factor may be increased to 0.95, provided that the conditions in clause 3.16 are not varied.
3.19 Design of Concrete Mixes Each mix design shall be such that: (i)
The aggregate shall comprise both fine aggregate and coarse aggregate with a combined grading consistent with the production of dense concrete. The maximum size of coarse aggregate shall be 20mm or 40mm as approved by the S.O.
(ii)
The cement content shall not be below the minimum specified for the grade of concrete or as approved by the S.O.
(iii)
The maximum free water/cement ratio shall be the maximum water/cement ratio when the aggregate is saturated but surface dry.
(iv)
The mixes shall be designed to produce a targeted mean concrete cube strength at 28 days after manufacture and shall be greater than the characteristic strength at 28 days by a margin of at least 5 N/sq.mm for grade C15 and 7.5 N/sq.mm for grades C20, C25, C30, C35A and C40.
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(v)
Where sufficient data can be produced by the Contractor to show that the standard of acceptance for characteristic strength can be maintained using a lower margin, the mix may be redesigned to have such reduced margin. Sufficient data shall consist of cube test results from at least 40 separate batches of concrete produced over a period exceeding 5 days but not exceeding 6 months by the same plant under similar supervision. The reduced margin shall be 1.64 times the standard deviation of the test results considered, but not less than 5 N/sq.mm for grade C15 and 3.75 N/sq.mm for grades C20, C25, C30, C35A and C40.
For any concrete containing admixtures, the strengths shall not be less than those specified but the mixes for the grade of concrete shall be separately designed to take account of the effects of the admixtures, and shall have separate trial mixes made and tested.
3.20 Trial Mixes As soon as the S.O. has approved each of the concrete mix designs, two batches from a trial mix for each grade shall be produced in a laboratory using cement and surface dry aggregates known to be typical of the proposed source of supply. The proposed mix proportions of each grade shall be approved only if both batches have the correct cement content and a free water cement ratio at or below the maximum value for the proposed degree of workability. When mix proportions have been approved by the S.O., three further batches of concrete for each grade shall be made at Site under full scale production conditions using the same mixing time and handled by means of the same plant which the Contractor proposes to use in the Works. The proportions of cement, aggregates and water, shall be carefully determined by weight in accordance with the Contractor’s approved mix design, and sieve analyses shall be made, by the method described in BS 812, of fine aggregate and each nominal size of coarse aggregate used. The compacting factor of each batch of each trial mix shall be determined immediately after mixing by the method described in BS 1881 and shall not be outside the limits specified in Section 3.19. Three 150mm compression test cubes from each of the three batches shall be made by the Contractor in the presence of the S.O. from each trial mix. The cubes shall be made, cured, stored and tested at 28 days after manufacture in accordance with the method described in BS EN 12390-1. If the average value of the compressive strength of the nine cubes taken from any trial mix is less than the target mean strength used in the mix design or if any individual cube test result falls below 85% of the target mean strength, the Contractor shall re-design that mix and make a further trial mix and set of test cubes. A full scale test of the workability of each trial mix of each grade of concrete shall be made by the Contractor in the presence of the S.O. The trial mix of each grade of concrete shall be batched, mixed and then transported for representative distance in the manner that the Contractor proposes to batch, mix and transport the concrete to be placed in the Works. After discarding the first batch so made, the concrete from later batches shall be placed and compacted in trial moulds both for reinforced and mass concrete with dimensions typical of the Works in accordance with the procedures described in later clauses, the sides of the moulds being capable of being stripped without undue disturbance of the concrete placed therein. The sides of the moulds shall be stripped after the concrete has set and the workability judged by the surface appearance and compaction obtained. If the workability test shows that the workability required is not attained for any trial mix for any grade of concrete, the trial mix shall be re-designed by the Contractor and a further full scale workability test undertaken for that trial mix.
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The re-design of the concrete mixes and the making and testing of trial mixes of concrete shall be repeated for each grade of concrete until trial mixes of concrete have been established which meet the specified requirements and have the required workability as demonstrated in the full scale workability test described above. If at any time during the construction of the Works the S.O. approves a change in the source of cement or aggregate or if the grading of the aggregate alters to such an extent that the fraction of aggregate retained on any sieve cannot be maintained within 2% of the total quantity of fine and coarse aggregate when adjusted as specified for sampling and testing of aggregates, then further trial mixes of concrete shall be made, tested and approved for use.
3.21 Material Batching All cement used in the manufacture of concrete shall be measured by weight either with an approved weighing machine or by making the size of each batch of concrete such as to require an integral number of complete bags or drums of cement. For concrete of grades C20, C25, C30, C35A and C40, the fine aggregate and the several nominal sizes of coarse aggregate shall be measured singly or cumulatively by weight using weigh-batching machines. For concrete of grade C15, the fine and coarse aggregate shall be measured separately either by weight using weigh-batching machines or by volume in gauge boxes. Weigh-batching machines shall provide facilities for the accurate control and measurement of the aggregates either singly or cumulatively and shall be capable of immediate adjustment by semi-skilled operators in order to permit variations to be made to the mix. All weigh dials shall be easily visible from the place at which filling and emptying of the hoppers is controlled. Every concrete mixing machine shall be fitted with a device to measure added water by weight and shall be so constructed that the water inlet and outlet valves are interlocked so that either one of them cannot be opened unless the other is fully closed. The weighing device shall be provided with an overflow with a cross-sectional area at least four times that of the inlet pipe and with its discharge point clear of the mixing plant. The entire water system shall be maintained free of leaks at all times and the measuring device shall be fitted with a drain pipe which allows the full quantity of water being measured to be drained off for checking the measurement. The outlet arrangement of the measuring device shall be such that between 5 and 10 % of the water enters the mixer before the other materials and a further 5 to 10 % of the water enters the mixer after the other materials. The remainder of the water shall be added at a uniform rate with the other materials. The water measuring device shall be readily adjustable so that the quantity of water added to the mixer can, if necessary, be varied for each batch. Where volume batching is permitted by the Specification, gauge boxes shall be soundly constructed of timber or steel to contain exactly the volume of the various aggregates required for one batch of each mix. They shall have closed bottoms and shall be clearly marked with the mix and aggregate for which they are intended. When calculating the size of the gauge box for fine aggregate, an allowance shall be made for the bulking of the fine aggregate due to the average amount of moisture contained in the stockpiles on the Site. Before the Contractor puts any gauge box into use on the Site he shall obtain the approval of the S.O. of the size and construction of such gauge box.
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Any admixtures which may be used shall be measured separately in calibrated dispensers. The Contractor shall submit details of the admixtures to the S.O. for his approval before such admixtures are allowed to be used in the Work. All mixing and batching plants shall be maintained free of set concrete or cement and shall be clean before commencing mixing. The accuracy of calibration of any weighing plant, water measuring plant and admixture dispenser, shall be checked before carrying out trial mixes, before mixing concrete for inclusion in the Works, after each service or adjustment to the mixing plant, and in any case at least once per month.
3.22 Mixing Concrete Concrete shall be mixed in batches in plant capable of combining the aggregates, cement and water (including admixtures, if any) into a mixture uniform in colour and consistency, and of discharging the mixture without segregation. On commencing work with a clean mixer, the first batch shall contain only half the normal quantity of coarse aggregate to compensate for the adhesion of the other materials to the drum. The moisture contents of the aggregates shall be determined before the commencement of each day's concreting and at such intervals during each day as may be necessary. The Contractor shall make due allowance for the water contained in the aggregates when determining the quantity of water to be added to each mix, and shall adjust the amount of water added to each mix to maintain constant the approved free water/cement ratio of the mixed concrete.
3.23 Ready-mixed Concrete In case of non compliance, the S.O. reserves the right to rescind the approval of ready mixed concrete. The Contractor shall satisfy the S.O. that ready-mixed concrete complies with the Specification in all respects, and that the manufacturing and delivery resources of the proposed supplier are adequate to ensure proper and timely completion of each concreting operation. The specified requirements as to the sampling, trial-mixing, testing and quality of concrete of various grades shall apply equally to ready-mixed concrete. Any additional facility, which the S.O. may require for the supervision and inspection of the batching, mixing and transporting of ready-mixed concrete shall be provided by the Contractor. In any case no ready-mixed concrete shall be allowed to be used after 45 minutes of initial mixing.
3.24 High Alumina Cement The composition of high alumina cement shall comply with BS 4550 – 6 & BS 14647. It shall consist of a minimum of 32% of alumina and the minimum compressive strengths of mortar cubes at one and three days shall be 42 N/sq.mm and 48 N/sq.mm respectively. High alumina cement shall not be used in structural concrete including foundations under tropical conditions where substantial reduction in strength has been experienced.
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3.25 Preparing for Concreting Before placing concrete the Contractor shall remove from the surface of the foundations or previously placed concrete, all oil, loose fragments of rock, earth, mud, timber and other debris, and standing water, to the satisfaction of the S.O. Where specified and elsewhere as ordered by the S.O., the excavated surfaces shall be prepared as specified under concrete protection.
3.26 Transporting Concrete Concrete shall be conveyed from the mixer to its place in the Works as rapidly as possible by methods which will prevent segregation or drying out and ensure that the concrete is of the required workability at the time of placing. If segregation has nevertheless occurred in any instance, the materials shall be remixed or rejected.
3.27 Placing concrete Concrete shall be placed and compacted before the initial set has occurred and, in any event, not later than 45 minutes from the time of mixing. When pneumatic placers are used, if the end of the placer pipe is not equipped with an energy absorbing device, it shall be kept as close to the work as practicable. Mortar or water used at the beginning or end of a run shall be discharged outside the formwork. When pumps are used, the end of the supply pipe shall be kept immersed in the concrete during placing to assist compaction. Mortar and water used at the beginning or end of a run shall be discharged outside the formwork.
3.28 Concreting in Hot Weather In hot weather, the Contractor shall take steps to ensure that the temperature of the concrete as placed shall not exceed 32 deg. C and that the maximum internal temperature attained during setting does not exceed 70 deg. C. To achieve this, the Contractor shall provide sun shades over stockpiles of aggregate, cement silos, mixing water tanks and pipelines, and in addition shall carry out the first and as necessary other of the following procedures which shall be submitted to the S.O. for approval: (i)
Cool the mixing water and replace part of the water by chipped ice. The ice shall be completely melted by the time mixing is completed.
(ii)
Spray clean cool water over the aggregate stockpiles. The Contractor shall carry out regular tests on the aggregates to ensure that concentrations of sulphates or chlorides do not rise to unacceptable levels, and to ensure that moisture content determinations allow for such spraying.
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(iii)
Shade or wet the outside of the formwork.
(iv)
Apply a fine moisture (fog) spray of clean cool water to shaded areas immediately prior to placing concrete.
(v)
Pour concrete at night.
3.29 Compaction All concrete placed in-situ shall be compacted with power driven internal type vibrators supplemented by hand spading and tamping, except as otherwise approved by the S.O. The vibrators shall at all times be adequate in number, amplitude and power to compact the concrete properly and quickly throughout the whole of the volume being compacted. Spare vibrators shall be readily on hand in case of breakdown. Vibrators shall be inserted into the uncompacted concrete vertically and at regular intervals. Where the uncompacted concrete is in a layer above freshly compacted concrete the vibrator shall be allowed to penetrate vertically for about 100mm into the previous layer. In no circumstances shall vibrators be allowed to come into contact with the reinforcement or formwork nor shall they be withdrawn quickly from the mass of concrete but shall be drawn back slowly so as not to leave voids. Internal type vibrators shall not be placed in the concrete in a random or haphazard manner nor shall concrete be moved from one part of the work to another by means of the vibrators. The duration of vibration shall be limited to that required to produce satisfactory compaction without causing segregation. Vibration shall on no account be continued after water or excess grout has appeared on the surface.
3.30 Attendance of Steel Fixer and Carpenter During the concreting of all reinforced concrete, including prestressed concrete, a competent steel fixer and carpenter shall be in attendance on each concreting gang, to ensure that the reinforcement, formwork and embedded fittings are kept in position as work proceeds.
3.31 Curing of Concrete Concrete shall be cured by protecting the surface from the effects of sunshine, drying winds, frost, rain, running water or mechanical damage for a continuous period of four days when the cement used in the concrete is sulphate-resisting Portland cement and seven days when the cement used is the ordinary Portland Cement. The protection shall be applied as soon as practicable after completion of placing by one or more of the following methods as approved by the S.O.: (a)
by water sprays in continuous operation;
(b)
by covering with hessian or similar absorbent material, or sand, kept constantly wet;
(c)
after thorough wetting, by covering with a layer of waterproof fabric kept in contact with the concrete surface.
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(d)
by the application of an approved non-staining liquid curing membrane which is either self-removing or easily removed following curing period and which has a 75% moisture retention standard. The liquid shall be applied to formed surfaces immediately after stripping the formwork.
Liquid curing membranes (d) shall not be used on Class U1 surfaces where laitance is to be removed and aggregate exposed to provide a satisfactory bond for placing further concrete or mortar screeds or on surfaces where the S.O. is of the opinion that the appearance of the concrete surface will be affected.
3.32 Construction Joints A construction joint is defined as a joint in the concrete introduced for convenience in construction at which special measures are taken to achieve subsequent continuity without provision for further relative movement. Concrete placed to form the face of a construction joint shall have all laitance removed and the large aggregate exposed prior to the placing of fresh concrete. The laitance shall wherever practicable be removed when the concrete has set but not hardened by spraying the concrete surface with water under pressure or brushing with a wire brush sufficient to remove the outer mortar skin and expose the large aggregate without being disturbed. Where the laitance cannot be removed due to hardening of the concrete, the whole of the concrete surface forming the joint shall be treated by high pressure water jet, sand blasting, use of a needle gun or a scaling hammer to remove the surface laitance. Before concreting is resumed, all loose matter on the existing concrete surface shall be removed and the surface slightly wetted.
3.33 Dimensions and Surfaces of Finished Concrete Workmanship in formwork and concreting shall be such that concrete shall require no making good, surfaces being perfectly compacted, smooth and with no irregularities. Concrete surfaces for the various classes of unformed and formed finishes shall in any event not exceed the maximum permitted tolerances which shall be as shown in the table below except where expressly stated otherwise in the Specification or Drawings. In the table "line and level" and "dimension" shall mean the lines, levels and cross-sectional dimensions shown on the Drawings. Surface irregularities shall be classified as "abrupt" or "gradual". Abrupt irregularities include, but shall not be limited to; offsets and fins caused by displaced or misplaced formwork, loose knots and other defects in formwork materials, and shall be tested by direct measurement. Gradual irregularities shall be tested by means of a straight template for plane surfaces or its suitable equivalent for curved surfaces, the template being 3.0m long for unformed surfaces and 1.5m long for formed surfaces. Maximum tolerance in mm:
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Class of Finish U1 U2 U3 F1 F2 F3
Line and level
Abrupt irregularity
Gradual irregularity
Dimension
+/- 12 +/- 6 +/- 6 +/- 12 +/- 6 +/- 3
6 3 3 6 6 3
+/- 6 +/- 3 +/- 3 +/- 6 +/- 6 +/- 3
+12, -6 +12, -6 +/-6
3.34 Unformed Surfaces Finishes to unformed surfaces of concrete shall be classified as U1, U2, U3, 'spaded' or 'bonded concrete' or such other special finish as may be particularly specified. Where the class of finish is not specified, the concrete shall be finished to Class U1. Class U1 finish is the first stage for Class U2 and U3 finishes and for a bonded concrete surface. Class U1 finish shall be a levelled and screeded, uniform plain or ridged finish, which (unless it is being converted to Class U2, U3 or bonded concrete) shall not be disturbed in any way after the initial set and during the period of curing, surplus concrete being struck off immediately after compaction. Where a bonded concrete surface is specified, the laitance shall be removed from the Class U1 finish surface and the aggregate exposed while the concrete is still green. A spaded finish shall be a surface free from voids and brought to a reasonably uniform appearance by the use of shovels as it is placed in the Works. Class U2 finish shall be produced by manual or mechanical floating of the concrete surface after the initial set has taken place and the surface has hardened sufficiently. The concrete shall be worked no more than is necessary to produce a uniform 'sandpaper' finish free from screed marks. Class U3 finish shall be a hard smooth steel-trowelled finish. Trowelling shall not commence until the moisture film has disappeared and the concrete has hardened sufficiently to prevent excess laitance from being worked into the surface. The surface shall be trowelled under firm pressure and left free from trowel marks. The addition of dry cement, mortar or water will not be permitted during any of the above operations.
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3.35 Built in Pipes and Plant Wherever possible, pipes and other items of Plant passing through concrete structures shall be installed and connected to the remainder of the pipework system to ensure proper fit, and shall be built into the structure as work proceeds. Where this procedure is impracticable due to programme or other requirements, holes shall be formed for the items of Plant to allow them to be built in later after complete installation of the Plant. In no case shall individual pipes of a complicated pipework system including flanged joints be built into concrete structures before accurate fit of the whole system can be checked after complete installation. Where holes are formed these shall be of size and shape sufficient to permit proper placing and compaction of concrete or grout. The surfaces of the holes shall be treated to produce a 'bonded' surface before installation of Plant. Before building-in commences the Plant shall be adequately supported in position to prevent movement or damage during building-in. Concrete used for building-in shall be of the same grade as concrete of the member into which the plant is being built, except that the mix shall also incorporate an approved expanding additive used in accordance with the manufacturer's instructions. Concrete, mortar and grout shall be carefully placed and compacted around the Plant to avoid damaging or moving the Plant.
3.36 Structural Precast Concrete Structural units of precast concrete shall be manufactured in the grade of concrete and to the sizes and details shown on the Drawings. The concrete shall comply in every aspect with the provisions of the Contract whether such units are manufactured on the Site or obtained from other manufacturers. All cement, aggregate and other materials for precast concrete units with faces which are exposed either internally or externally shall be from the same sources throughout. Exposed surfaces of the units shall be uniform in colour and in texture. Formwork and unformed surfaces for precast concrete units shall comply with the requirements for F3 formed surfaces and U3 unformed surfaces except that the dimensional variations shall not exceed the values listed below, unless otherwise detailed on the Drawings. Length
+/- 6mm
Cross-section
+/- 6mm each direction
Straightness
6mm (deviation from intended line)
Flatness
3mm (deviation from a 1.5m straight edge placed in any position on a nominally plane surface).
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Squareness
when considering the squareness of a corner, the longer of the two adjacent sides being checked shall be taken as the baseline, and the shorter side shall not vary in its distance from the normal so that the differences between the greatest and the shortest dimension exceeds 6mm. When the nominal angle is other than 90 degrees, the included angle between the check lines shall be varied accordingly.
Twist
any corner on any nominally plane surface shall not be more than 6mm from the plane containing the other three corners.
The positions of individual connecting bolts, bolt holes, projecting steel and other devices in any associated group (e.g. the joint of two precast units) shall be within 3mm of their true position in the group in which they are cast. The location of any such group shall be within 6mm of its true position in the unit in which it is cast, provided that such deviation does not adversely affect the proper assembly of the whole structure. The Contractor shall submit to the S.O. for approval, full details of his proposed method of carrying out all operations connected with the manufacture and assembly of precast concrete structural members, including: -
a description of the types of casting bed, mould and formwork for the various types of members;
-
the procedure for concrete casting and the method of curing the concrete;
-
the procedure for transporting, handling, hoisting and placing of each type of precast structural member;
-
full details of temporary supports necessary to ensure adequate stability during erection, due account be taken of construction loads, including wind.
3.37 Installation of Precast Concrete Units At all stages and until completion of the work, precast members shall be adequately protected to preserve all permanently exposed surfaces, arrises and architectural features. The protection shall not mark or otherwise disfigure the concrete. All units shall be laid, bedded, jointed and fixed in accordance with the lines, levels and other details shown on the Drawings. Dry-pack mortar jointing for packing shall consist of one part by volume ordinary Portland cement and two and half parts by volume of fine aggregate passing a 1mm sieve. The mortar shall be mixed with only sufficient water to make the materials stick together when being moulded in the hands. The mortar shall be placed and packed in stages, wherever possible from both sides of the space being filled, using a hardwood stick hammer until the mortar is thoroughly compacted. Any precast concrete structural member which is found to be cracked, damaged or otherwise inferior in quality either before or after erection, shall be rejected and replaced by the Contractor.
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Section 3 - Concrete
3.38 Prestressed Concrete The Contractor shall submit to the S.O. for approval his proposed method of carrying out all operations connected with prestressed concrete work and his proposals for handling, hoisting and placing in position any precast prestressed concrete units. Prestressed concrete work whether precast or cast in-situ shall be as detailed on the Drawings and the Contractor shall provide full details of his proposed method of carrying out all operations connected with prestressing including:(a)
Design of concrete mix.
(b)
Description of concrete casting and curing operations.
(c)
Procedure for prestressing and method of checking and recording the extension and anchorage slip.
(d)
Procedure for handling, hoisting and placing of any precast units.
(e)
Grouting of ducts.
prestress, wire
All tendons, duct forming devices, anchorages and other components shall be kept free of mud, oil (except water soluble oil applied for protection), paint, retarders, loose rust, or other foreign matter. They shall be placed with a tolerance of +/- 3mm in concrete dimensions of 300mm or less or +/6mm in concrete dimensions over 300mm. The bearing surfaces between anchorages and concrete shall be normal to and concentric with the tendons and the line of action of the prestressing force.
3.39 Precast Concrete Products Precast concrete products shall where appropriate be constructed in accordance with British Standards as follows, being hydraulically pressed where possible: Type of Unit Concrete blocks Concrete kerbs etc. Concrete flags Concrete sills Concrete lintels
Standard BS EN 1170-1 BS EN 1339 & BS EN 1340 BS EN 1339 & BS EN 1340 BS 5642 BS 5977
The concrete shall comply in every aspect with the provisions of the Specification whether such products are manufactured on the Site or obtained from other manufacturers.
Typical Civil and Structural Engineering Specification for Sewerage Works Issue 01 / Rev 0 August 2008
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Section 3 - Concrete
3.40 Sampling and Testing of Aggregate The Contractor shall sample and carry out a mechanical analysis of the fine aggregate and each nominal size of coarse aggregate in use employing the methods described in BS 1881 at least once in each week when concreting is in progress and at such more frequent intervals as the S.O. may require. The grading of all aggregates shall be within specified limits and should the fraction of aggregate retained on any sieve differ from the corresponding fraction of aggregate in the approved mix by more than 2% of the total quantity of fine and coarse aggregate, the S.O. may instruct the Contractor to alter the relative proportions of the aggregates in the mix to allow for such difference.
3.41 Quality Control: Sampling and Testing of Concrete The Contractor shall provide the equipment necessary to determine the compacting factor of freshly mixed concrete at each place where concrete is being made and shall determine the compacting factor of the freshly mixed concrete by the method described in BS 12350 on each occasion that a set of test cubes is made and not less than once a day or as the S.O. may direct. For each grade concrete, works test cubes shall be made whenever required by the S.O. but not less frequently than as follows unless otherwise particularly specified: for concrete of grades C25, C30, C35A, C40
one set of cubes per 25 cu.m or part thereof concreted per day;
for concrete of grade C15 or C20:
one set of cubes per 50 cu.m or part thereof concreted per day.
Each set of cubes (six cubes per set) shall be made from a single sample taken from a randomly selected batch of concrete. Three cubes shall be tested 7 days after manufacture and three cubes 28 days after manufacture.
3.42 Compliance with Specified Requirements The concrete shall be deemed satisfactory provided that:(i)
The average 28 days strength determined from any group of four consecutive sets of three test cubes exceeds the specified characteristic strength by not less than 5 N/sq.mm for grade C15 concrete and 3.75 N/sq.mm for grades C20, C25, C30, C35A and C40.
(ii)
The average of each set of three test cube results is greater than 100% of the specified characteristic strength.
If only one set of three cube results fails to meet the second requirement, those results may be considered to represent only the particular batch of concrete from which the cubes were taken, provided that the average strength of the group satisfies the first requirement.
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Section 3 - Concrete
If more than one set of three cube results in a group fails to meet the second requirement or if the average strength of any group of four consecutive sets of three test cubes fails to meet the first requirement then all the concrete in all the batches represented by all such cubes shall be deemed not to comply with the strength requirements.
3.43 Non-Compliance When the average strength of four sets of three consecutive test cubes fails to meet the first requirement, no further concrete from that mix shall be placed in the work and the Contractor shall establish the cause of the failure and apply such remedies as are necessary. The Contractor shall demonstrate by trial mixes and test cube results that the revised mix is in accordance with the specified requirements. The Contractor shall within 24 hours of the date of test make proposals for agreement with the S.O. about action to be taken in respect of any concrete represented by test cubes which fail to meet either of the requirements. These proposals may include, but shall not be limited to, cutting and testing cores. Concrete which is ultimately found not to comply with any of the requirements of the Specification shall be rejected and shall be broken out and replaced or otherwise dealt with as agreed with the S.O.
3.44 Cutting and Testing of Core Samples As and where directed by the S.O. cylindrical core specimens of 150mm nominal diameter shall be cut normal to the face of the hardened concrete for the purpose of examination and testing. The procedure for drilling, examination, measurement and testing for compressive strength shall be in accordance with BS 12390. Prior to preparation for testing, the specimen shall be made available for examination by the S.O. If the crushing strength of the specimen determined in accordance with paragraph 114 of BS 12390 is less than the characteristic strength at 28 days for the grade requirements in other respects, the concrete in that part of the Works of which it is a sample shall be considered not to comply with the specified requirements.
3.45 Inspection Procedures Before any concrete is placed, the Contractor shall carry out an inspection to ensure that all preparations are complete, including the provision of the necessary equipment and personnel, and shall ensure that sufficient materials are available to complete the work proposed. After completion of this inspection the work shall be offered for inspection by the S.O., sufficient time being allowed for inspection and correction of any defects. No concrete shall be placed until the S.O. has inspected and approved the surfaces upon which the concrete is to be placed, the formwork and the reinforcing steel. Where required by the S.O. the Contractor shall institute a 'pour card' system in which a card is made out for each lift of concrete and is initialled by the Contractor and S.O. indicating that the inspections have been carried out.
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Section 3 - Concrete
The 'pour card' shall include spaces to identify the concrete being placed and to signify completion of the inspections by the Contractor and S.O. of the following items: -
preparation of surface on which concrete is to be placed; formwork; reinforcement; ready for concrete placing; inspection after removal of formwork (any remedial work shall be agreed and noted); curing procedures; completion of remedial work (if any).
3.46 Concrete Protection Systems Where required all structural concrete in contact with the ground shall be protected by one of the methods specified below. Unless otherwise specified or detailed on the Drawings, in-situ concrete surfaces which are to be protected shall have either U2 or F2 finish as appropriate. (a)
Prefabricated membrane tanking:
The membrane shall be preformed consisting of 1.5mm thick rubber/bitumen compound formulated for use in hot climates, backed with 0.3mm thick PVC sheet. The membrane shall adhere with watertight joints to itself at overlaps and to concrete surfaces prepared with suitable priming compound. The membrane and primer shall be applied in accordance with the manufacturer's instructions to horizontal, inclined and vertical surfaces. After the blinding concrete has hardened, the membrane shall be applied, bitumen face downwards, and shall extend at least 150mm beyond the outer limits of the structure. As soon as the membrane has been applied and before any reinforcement or structural concrete is placed, the membrane shall be covered by a sand/cement screed 50mm thick, extending over the whole area of the base of the structure. The membrane projection of 150mm shall be temporarily protected with a layer of board as specified below to prevent mechanical damage. After the concrete structure has been constructed up to ground level and curing is completed, the surfaces which will be in contact with the ground, or as detailed otherwise on the Drawings, shall be primed with the material supplied by the membrane manufacturer. The vertical membrane shall be bonded onto the projection of the base membrane and terminated in a chase at the top. Fillets and reinforcing strips shall be used. Completed areas of vertical membrane shall be protected from mechanical damage during backfill operations by 12mm thick cardboard, fibreboard or chipboard secured with suitable adhesive, or by concrete blockwork. (b)
Made-in-place membrane tanking:
As an alternative to prefabricated membrane tanking on horizontal surfaces, the Contractor may propose to design, supply and install a made-in-place membrane of bitumen asphalt concrete laid on a tack coat placed on clean original ground. The bitumen asphalt concrete shall comprise bitumen or asphalt and coarse and fine aggregates.
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Section 3 - Concrete
The Contractor shall demonstrate to the S.O. by testing, by trial and by experience that made-in-place membrane tanking exhibits characteristics which are in all respects equal to or better than prefabricated membrane tanking. The system shall be: -
waterproof during life of protected structure; robust during preparation for concreting; durable during life of structure; flexible in differential settlement; incompressible under weight of structure.
Made-in-place membrane tanking may be used in place of blinding concrete provided that the Contractor shall also have demonstrated to the S.O. the practicability of this system by testing, by trial and by experience. Vertical or sloping concrete surfaces shall be protected by prefabricated membrane tanking as specified which shall overlap and adhere to made-in-place membrane tanking over a width of 150mm. (c)
Bituminous latex emulsion:
This material shall only be used as an alternative to membrane tanking where the S.O. has specifically agreed that satisfactory membrane tanking cannot be carried out. The emulsion shall be a rubber-rich bituminous emulsion suitable for use in hot climates and capable of building up a film with minimum dry thickness of 1.0mm, which is impermeable to water penetration and possessing a high degree of flexibility. A priming mixture shall be made by thoroughly mixing 1 part emulsion with 6 parts fresh water. Coats other than priming coat shall not be diluted. Application rates shall be as follows: Surface Horizontal
Vertical
Coat 1st (priming) 7 2nd 3rd 1st (priming) 7 2nd 3rd 4th
Application rate (sq.m/litre) 1 1.5
2 2 2
or as necessary to build up a minimum dry film thickness of 1.0mm. Overcoating shall take place as soon as the previous coat has dried. Immediately the final coat has been applied to vertical surfaces, bituminised building paper shall be applied to the fresh emulsion and pressed into close contact over the whole area of the protection. Horizontal and vertical surfaces shall be protected from mechanical damage during subsequent construction work by screed or boarding as specified for membrane tanking.
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Section 3 - Concrete
(d)
Polyethylene sheet
250 micron polyethylene sheet shall be placed against vertical or sloping surfaces of excavated ground before placing concrete directly against such surfaces. Backfilling with sand against protected surfaces shall be carried out in such a manner that the protection is not damaged. Nevertheless, if such damage occurs, the damage shall be made good to the satisfaction of the S.O.
3.47 Concrete Protection Procedures Details of concrete protection shall be shown by the Contractor on the preliminary working drawings. Such details shall include corners overlaps, brick or board protection and details for curved faces, etc. Concrete protection systems proposed for use in the Works shall be demonstrated by the Contractor to the S.O. for approval before submission of preliminary working drawings showing use of such systems in the Works.
3.48 Machinery Bases and Grouting In Bases to take machinery and associated pipeworks shall be constructed in fair faced concrete to the dimensions shown on the approved machinery drawings or as ordered by the S.O. The mounting surface of the base shall be steel floated to true and level planes. The structural concrete on which the bases are to be erected shall be prepared by hacking and cleaning off. Bases shall be tied to the structural concrete with vertical reinforcement. Horizontal reinforcement shall also normally be provided at the level of the pockets for the holding down bolts. Bolt pockets and lead-ins for grout shall be formed by a means which shall have the approval of the S.O. Polystyrene formers will not be permitted. Where expanded metal is used as a former it shall be left in. When the machinery has been erected the bolt pockets shall on approval of the S.O. be completely filled using a mixture of 2 parts of cement to 3 parts sand by volume with sufficient water to form a thick creamy consistency. The machinery shall be run under the supervision of the Contractor and witnessed by the S.O. after the grout has hardened. When so directed the Contractor shall complete the grouting operation by filling the space between the top of the concrete and the underside of the machinery base plate.
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Section 3 - Concrete
3.49 Epoxy Protective Coating for Concrete Surfaces General The descriptions on the epoxy protective coating covers all labour, materials, equipment and services necessary to complete its application concrete surfaces. The following standards shall be used for reference and in the event when a conflict arises which requires for more detailed information: 1. 2. 3. 4. 5. 6. 7. 8. 9. 10.
ASTM D638 – Tensile Properties of Plastics. ASTM D790 - Flexural Properties of Unreinforced and Reinforced Plastics. ASTM D695 – Compressive Properties of Rigid Plastics. ASTM D4541 – Pull-off Strength of Coatings Using Portable Adhesion Tester. ASTM D2584 – Volatile Matter Content. ASTM D543 – Resistance of Plastics to Chemical Reagents. ASTM C109 – Compressive Strength Hydraulic Cement Mortars. ASTM C579 – Compressive Strength of Chemically Setting Silicate and Silica Chemical Resistance Mortar. SSPC – The published standards of the Society of Protective Coatings, Pittsburgh, PA. SSPC SP-13/NACE No.6 - Surface Preparation of Concrete.
Material Specifications The epoxy to be used must be safe for handling and does not pose a danger to health and the environment. It must be an approved type by SIRIM, JPP, IWK and other relevant bodies. It must be suitable for repair and coating of new and existing manholes, pumping stations, concrete holding and mixing tanks, etc. The epoxy can be either a coal tar or non-coal tar type. Coal tar epoxies are essentially a mix of coal tar and epoxy resins and only come in a tar black colour. It must be readily applied to damp concrete surfaces and able to provide a strong bond to the concrete to prevent the ingress of water. It must be low viscosity for ease of application within confined areas, non-blushing and non-water spotting. The epoxy coating must have excellent chemical, corrosion and abrasive resistance against wastewater. Also, it must be smooth, glossy and easy to clean to ensure a long maintenance-free life. It must be solvent free and of high-build epoxy system. Coal tar epoxies shall be of the amine cured and not amide cured system. The Contractor shall warranty all works against defects in materials and workmanship for a period of one (1) year, unless otherwise stated, from the date of final acceptance of the project. The Contractor shall, within a reasonable time after receipt of written notice thereof, repair defects in materials or workmanship which may develop during the warranty period and any damage to other work caused by such defects or repairing of same at his own expenses and without cost to the Owner. The protective coating must be able to provide a maintenance-free life and last until the next maintenance inspection which normally will be carried out after 5 years from the date of application. Submittals: Prior to use, the Contractor must submit the product data to the S.O. for approval. The information required includes: a)
Technical data sheet on each product to be used.
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Section 3 - Concrete
b) c) d) e) f)
Material Safety Data Sheet (MSDS) for each of the product to be used. Copies of independent testing performed on the coating product indicating the product meets the requirements as specified therein. Technical data sheet and project specific data for materials to be top-coated with the coating product(s) including application, cure time and surface preparation procedures. Current documentation from coating product manufacturer certifying the Contractor’s training and equipment complies with the quality assurance requirements specified therein. At least (5) recent references of the Contractor indicating successful application of coating product(s) of the same material type as proposed.
Quality Assurance a)
b) c)
d)
e) f) g)
Epoxy coating product(s) shall be capable of being applied and cured properly within a manhole or confined environment. Coating product(s) shall be resistant to all forms of chemical or bacteriological attack found in municipal sanitary system and capable of adhering to the manhole structure substrates. Repair product(s) shall be fully compatible with epoxy coating product(s) including ability to bond effectively forming a composite system. The Contractor shall utilize equipment for the spray application of the epoxy coating products which has been approved by the manufacturer. The Contractor shall also have received training on the operation and maintenance of said equipment from the manufacturer. The Contractor shall be trained or have their training approved and certified by the epoxy coating product manufacturer for the handling, mixing, application and inspection. Only competent and certified applicator(s) shall be allowed to carry out the coating application. Inspectors shall be trained in the use of testing or inspection instrumentation and knowledgeable of the proper use, preparation and installation of the coating product(s). The Contractor shall initiate and enforce quality control measures consistent with the epoxy coating product manufacturer recommendations. Prior to epoxy coating application, a pre-construction meeting shall take place. At the meeting, important issues regarding materials and application need to be addressed.
Delivery, Storage and Handling a) b)
Materials shall be kept dry, protected from weather and stored under waterproof cover. Epoxy materials shall stored between 10oC and 32o C. The epoxy materials shall not be stored near flame, heat or strong oxidants. c) Epoxy materials shall be handled properly according to the material safety data sheets. Surface Preparation Appropriate actions shall be taken by the Contractor to comply with the local, state and federal regulatory and other applicable agencies with regard to environment, health and safety during work. All structures to be coated shall be made readily accessible by the Contractor. The standard Portland cement or new concrete (not quick setting high strength cement) must be cured a minimum of 28 days prior to application of the epoxy coating. Any active flows shall be dammed, plugged or diverted as required to ensure all liquids are maintained below or away from the surfaces to be coated. The temperature of the surface to be coated should be maintained between 5oC and 50oC. Prior to commencing surface preparation, the Contractor shall inspect all surfaces specified to receive the coating and notify the S.O., in writing, of any noticeable disparity at the site, structure or surfaces which may interfere with the work, use of materials or procedures as specified.
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Section 3 - Concrete
The concrete surface must be clean, dry and free from laitance and loose particles. Contaminants such as oil, grease, wax, dust, efflorescence and organic growth shall be removed. Incompatible previous coating also must be removed from the concrete surface prior to application of the epoxy which may affect the performance and adhesion of the epoxy coating to the substrate. Infiltration shall be stopped by using a material which is compatible with the repair products and is suitable for top-coating with the epoxy material(s). Choice of surface preparation method(s) shall be based upon the condition of the structure and concrete or masonry surface, potential contaminants present, access to perform work and required cleanliness and profile of the prepared surface to receive the coating product(s). Surface preparation method or combination of methods that may be adopted include high pressure water cleaning, high pressure water jetting, abrasive blasting, hot water blasting, etc. Whichever method(s) used, they shall be performed in a manner that provides a uniform, sound clean neutralized surface suitable for the specified epoxy coating. For repairing and resurfacing works, repair products shall be used first to fill voids, bug holes and/or smooth the transition between the components prior to the installation of the epoxy coating. Repair materials must be compatible with the specified coating and shall be used and applied in accordance with the manufacturer’s recommendations. Resurfacing product shall be used to fill large voids, lost mortar in masonry structures, smooth deteriorated surfaces and rebuild severely deteriorated structures in order to provide a concrete or masonry substrate suitable for the epoxy coating. These products shall be installed to minimum thickness as recommended by the manufacturer. Repair and resurfacing products shall be handled, mixed, installed and cured in accordance with manufacturer’s guidelines. All repaired or resurfaced surfaces shall be inspected for cleanliness and suitability to receive the epoxy coating. Additional surface preparation shall be performed prior to coating application, if necessary. The following criteria shall be used in selecting and accepting compatible repair and resurfacing products for use within the specifications: • •
100% solids, solvent-free epoxy grout specifically formulated for epoxy top-coating compatibility. Factory blended, rapid setting, high early strength, fibre reinforced, non-shrink repair mortar that can be trowelled or pneumatically spray applied may be approved if specifically formulated to be suitable for top-coating with the specified coating product(s).
Epoxy coating application shall only be carried out using the manufacturer’s approved plural components spray equipment. Hand tools may be used on hard to reach areas, primer application and touch-up works. Application Application procedures shall conform to the recommendations of the epoxy coating manufacturer including environmental controls, product handling, mixing, application equipment and methods. The spray equipment shall be specifically designed to accurate ratio and apply the coating and shall be in proper working order. Only competent and certified applicator(s) shall perform all aspects of epoxy coating installation.
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Section 3 - Concrete
Prepared surfaces shall be coated by spray application of the coating product(s) to the minimum wet film thickness. The thickness for coal tar epoxy shall be up to 35 mils (875 microns) in two coats. For epoxy resins based, the thickness per coat shall be at least 8 mils (200 microns) of dry film and wet film each. Top-coating or additional coats of the epoxy coating shall occur within the product’s recoat window. Additional surface preparation procedures will be required if the recoat window is exceeded. The coating thickness may vary depending on substrate and manufacturer’s recommendation based on project assessment. The epoxy coating shall interfere with adjoining construction materials throughout the manhole structure to effectively seal and protect concrete or masonry substrate from infiltration and attack by corrosive elements. Procedures and materials necessary to effect the interface shall be as recommended by the product manufacturer. Sewage flow shall be stopped, bypassed or diverted for application of the epoxy coating to the invert of manholes and interface with pipe materials. Testing and Inspection During application of the protective coating, measurement shall be taken, verified and documented by the Contractor for submission to the S.O. Holiday Detection is recommended for coating systems installed in corrosive environment, when it can be safely and effectively performed. Structure size and active flowing liquids, however, may restrict the use of holiday detection. After the coating product(s) have set in accordance with manufacturer instruction, all surfaces shall be inspected for holidays with high-voltage holiday detection equipment. Reference can be made from NACE RPO 188-99 for performing holiday detection. All detected holidays shall be marked and repaired by abrading the coating surface with grit disk paper or other hand tooling method. After abrading and cleaning, additional coating can be hand applied to the repair area. All touch-up/repair procedures shall follow the coating manufacturer’s recommendations. Contractor shall provide documentation on areas tested, results and repairs made to S.O. Adhesion Testing is a destructive test method and should be used in moderation as an evaluation tool. A minimum of 10% of the manholes coated shall be tested for adhesion/bond of the coating to the substrate. Testing shall be conducted in accordance with ASTM D4541 as modified herein. The S.O. shall select the manholes to be tested. A minimum of three 20 mm dollies shall be affixed to the coated surface at the cone area, mid section and at the bottom of the structure. The adhesive used to attach the dollies to the coating shall be rapid setting with tensile strengths in excess of the coating product and permitted to cure in accordance with manufacturer’s recommendations. The coating and dollies shall be adequately prepared to receive the adhesive. Failure of the dolly adhesive shall be deemed a non-test and require retesting. Prior to performing the pull test, the coating shall be scored to within 30 mils of the substrate by mechanical means without disturbing the dolly or bond within the test area. Two of the three adhesion pulls shall exceed 200 psi or concrete failure with more than 50% of the subsurface adhered to the coating. Should a structure fail to achieve two successful pulls as described above, additional testing shall be performed at the discretion of the S.O. The S.O. shall evaluate any areas detected to have inadequate bond strength. Further bond tests may be performed in that area to determine the extent of potentially deficient bonded area and the Contractor shall make repairs. The S.O. shall make a visual inspection. Any deficiencies in the finished coating shall be marked and repaired according to the procedures set forth herein by the Contractor.
Typical Civil and Structural Engineering Specification for Sewerage Works Issue 01 / Rev 0 August 2008
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Section 4 - Formwork
4.0
FORMWORK
4-1
4.1
Scope
4-1
4.2
Submissions
4-1
4.3
Materials
4-1
4.4
Design and Detailing
4-1
4.5
Formed Surfaces - Class of Finish
4-1
4.6
Erection of Formwork
4-2
4.7
Removal of Formwork
4-3
4.8
Building in Plant
4-3
4.9
Dry-pack Mortar
4-4
4.10 Defects in Formed Surfaces
4-4
4.11 Movement Joints
4-5
4.12 Sliding Planes and Joints
4-6
4.13 Inspection and Testing
4-6
Typical Civil and Structural Engineering Specification for Sewerage Works Issue 01 / Rev 0 August 2008
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Section 4 - Formwork
4.0 Formwork 4.1
Scope
This section covers the supply, erection and removal of formwork, the finishes to be attained and the remedial action to be taken to the finished concrete after removal of formwork.
4.2
Submissions
The Contractor shall submit calculations and designs for formwork including layout of panels, before fabrication commence.
4.3
Materials
Formwork shall be constructed of timber, sheet metal or other approved material. The Contractor shall also furnish all struts, braces and ties to withstand the placing and vibrating of concrete, all construction loads and the effects of weather. Form ties shall be of rod and cone or other approved proprietary type. They shall be designed so that no part remaining embedded in the concrete after formwork has been removed shall be nearer than 50mm from the surface in the case of reinforced concrete and 150mm in the case of unreinforced concrete. Form ties for use in water-retaining structures shall incorporate a diaphragm not less than 50mm diameter welded to the mid point of the tie, designed to prevent water passing along the tie.
4.4
Design and Detailing
The Contractor shall be responsible for the adequacy and safety of formwork. On formwork to external faces which will be permanently exposed, all horizontal and vertical formwork joints shall be so arranged that joint lines shall form a uniform pattern on the face of the concrete. Where the Contractor proposes to make up the formwork from standard sized manufactured formwork panels, the size of such panels shall be approved by the S.O. before they are used in the construction of the work. The finished appearance of the entire elevation of the structure and adjoining structures shall be considered when planning the pattern of joint lines caused by formwork and by construction joints to ensure continuity of horizontal and vertical lines.
4.5
Formed Surfaces - Class of Finish
Finishes to formed surfaces of concrete shall be classified as F1, F2 or F3 as specified in Section 3. Where the class of finish is not specified the concrete shall be finished to Class F1.
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Section 4 - Formwork
Formwork for class F3 finish shall be lined with panels of non-staining material with a smooth unblemished surface such as sanded plywood or hard compressed fibre board. The panels shall be as large as possible and shall be arranged in a uniform approved pattern and fixed to back formwork by oval nails. Unfaced wrought boarding or standard steel panels will not be permitted. Ribbed finishes shall be formed by a backing of sanded plywood or hard compressed fibre board, as described for a Class F3 finish, against which timber battens are fixed. Battens shall have clean sharp arises at base and be stopped with a waterproof filler and be sanded to give a smooth surface. Battens shall be securely fixed to the backing by adhesive and screws to prevent the penetration of grout behind them. Formwork for Class F2 finish shall be faced with wrought tongued and grooved boards or plywood or metal panels arranged in a uniform approved pattern free from defects likely to detract from the appearance of the surface. Formwork for Class F1 finish shall be constructed of timber, sheet metal or any suitable materials which will prevent loss of grout when the concrete is vibrated. Surfaces subsequently to be rendered, plastered or tiled shall be adequately scabbled or roughened as soon as the formwork is removed to reduce the irregularities to not more than half the thickness of such rendering, plastering or bedding for tiles and to provide a satisfactory key.
4.6
Erection of Formwork
All formwork shall be soundly constructed, firmly supported, adequately strutted, braced and tied to withstand the placing and vibrating of concrete, construction loads and the effects of weather. Formwork shall not be tied to or supported by reinforcement. Faces of formwork in contact with concrete shall be free from adhering foreign matter, projecting nails and the like, splits or other defects, and all formwork shall be clean and free from standing water, dirt, shavings, chippings or other foreign matter. Joints shall be sufficiently watertight to prevent the escape of mortar or the formation of fins or other blemishes on the face of the concrete. All exposed exterior angles on the finished concrete of 90 deg. or less shall be given 20mm by 20mm chamfers. Formwork shall be provided for the top surfaces of sloping work where the slope exceeds 15 deg. from the horizontal (except where such top surface is specified as spaded finish) and shall be anchored to enable the concrete to be properly compacted and to prevent air being trapped. Formwork in contact with the concrete shall be treated with a suitable non-staining mould oil prior to reinforcement and concrete placement to prevent adherence of the concrete. Care shall be taken to prevent the oil from coming in contact with reinforcement or with concrete at construction joints. Surface retarding agents shall not be used unless specified. Where ties are built into the concrete for the purpose of supporting formwork, the whole or part of any such supports shall be capable of removal so that no part remaining embedded in the concrete shall be nearer than 50mm from the surface in the case of reinforced concrete and 150mm in the case of unreinforced concrete. Holes left after removal of such supports shall be neatly filled with well rammed dry-pack mortar.
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Section 4 - Formwork
Openings for inspection of the inside of the formwork, for the removal of water used for washing down and for placing concrete shall be provided and so formed as to be easily closed before or during placing concrete. Before placing concrete all bolts, pipes or conduits or any other fixture which are to be built in shall be held fast by fixing to the formwork or otherwise. Holes shall not be cut in any concrete without prior approval of the S.O.
4.7
Removal of Formwork
Formwork shall be so designed as to permit easy removal without resorting to hammering or levering against the surface of the concrete. The periods of time elapsing between the placing of the concrete and the striking of the formwork shall be as approved by the S.O. after consideration of the loads likely to be imposed on the concrete and shall in any case be not less than the periods shown in the following table. Where soffit formwork is constructed in a manner that allows the removal of the majority of the formwork and the retention during and after such removal of a sufficient number of adequate supporting props in an undisturbed condition, the Contractor may with the agreement of the S.O. remove the formwork at the earlier times listed below provided that the props are left in position and are not disturbed during removal of the majority of the formwork. Position
Time for striking using ordinary Portland cement normal weather days
Beam sides, walls and columns Slabs (props left under) Props to slabs Beam soffits (props left under) Props to beams
1 5 14 10 21
Notwithstanding the foregoing, the Contractor shall be held responsible for any damage arising from removal of formwork before the structure is capable of carrying its own weight and any incidental loading.
4.8
Building in Plant
The Contractor shall erect all formwork, struts and other temporary work to enable Plant to be built in, and such formwork shall be designed to allow placing of the concrete, mortar or grout so as to fill the voids completely, and to enable air to escape from any cavities during filling. The formwork shall be sealed against pipework and other items of Plant to prevent leakage of grout. Formwork shall be supported independently of all Plant and pipework. The Contractor shall use such templates and moulds as are necessary to achieve the accurate positioning of such items.
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Section 4 - Formwork
4.9
Dry-pack Mortar
Dry-pack mortar for filling holes and repairing surface blemishes shall be made from one part by weight of cement and three parts fine aggregate passing a 1mm sieve. The colour of the mortar shall match that of the surrounding concrete. The mortar shall be mixed with only sufficient water to make the materials stick together when being moulded in the hands. The dry-pack material shall then be placed and packed in layers having a thickness not greater than 15mm. The compaction shall be carried out by use of hardwood stick and hammer and shall extend over the full area of the layer, particular care being taken to compact the dry-pack against the sides of the hole. After compaction the surface of each layer shall be scratched before further loose material is added. Holes shall not be over filled and the surface shall be finished by laying the hardwood block against the dry-pack fill and striking the block several times. Steel finishing tools shall not be used and water shall not be added to facilitate finishing.
4.10 Defects in Formed Surfaces Workmanship in formwork and concreting shall be such that concrete shall require no making good, surfaces being perfectly compacted and smooth. Any surface blemishes shall be repaired by the Contractor, at his expense, to the satisfaction of the S.O. immediately after removal of formwork. Any remedial treatment to concrete surfaces shall be agreed with the S.O. No rendering of finished surfaces to make good shall be allowed. Any concrete the surface of which is found to have been treated before inspection by the S.O. shall be rejected. Remedial measures may include, but shall not be limited to, the following: -
holes left by the formwork supports shall be thoroughly cleaned out to remove all loose material and the sides shall be roughened, if necessary, to ensure a satisfactory bond: they shall then be filled with an approved proprietary epoxy resin mortar or with dry-pack mortar if agreed by the S.O.;
-
fins, pinhole bubbles, surface discolouration and minor defects may be rubbed down with sacking and cement immediately the formwork is removed;
-
abrupt and gradual irregularities may be rubbed down with carborundum and water after the concrete has been fully cured;
-
small defects and minor honeycombing shall be chipped out normal to the face of the concrete to a depth of at least 25mm and filled with an approved proprietary epoxy resin mortar or with dry-pack mortar if agreed by the S.O.
Where deeper or more extensive defects occur, the Contractor shall obtain the approval of the S.O. to the methods of repair proposed which may include, but shall not be limited to, cutting out to a depth of 25mm with a diamond saw to give a regular edge to the repair and further chipping to form a hole with dovetail shape to sound concrete or to a total depth of 75mm whichever is the greater.
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Section 4 - Formwork
If reinforcing steel is exposed, the concrete shall be removed to a depth of 25mm beyond the back side of the reinforcement. Steel mesh reinforcement shall then be sprung into the dovetail. The void shall be refilled with concrete or suitable approved epoxy resin mortar. The Contractor shall thoroughly clean any hole or defective area that is to be filled and where the surface has been damaged the Contractor shall break out any loose, broken or cracked concrete or aggregate. Where the remedial work is to be carried out using dry-pack mortar or concrete, the concrete surrounding the hole shall be thoroughly soaked after which the surface shall be dried so as to leave a small amount of free water on the surface. The surface shall then be dusted lightly with cement by means of a small dry brush until the whole surface that will come into contact with the dry-pack mortar has been covered and darkened by absorption of the free water by the cement. Any dry cement in the hole shall be removed. Dry-pack mortar shall be mixed and placed as specified. Where concrete is to be used, the concrete mix shall be approved by the S.O. and shall be placed and compacted into the hole, using formwork as necessary. Where the remedial work is to be carried out using epoxy resin mortar or other specialist material, the surface of the cleaned hole shall be prepared and primed and the repair material placed, compacted and finished in accordance with the manufacturer's instructions. Where in the opinion of the S.O., the defect is too extensive to permit satisfactory repair, either from the point of view of structural integrity or appearance, the concrete containing the defect shall be broken out and replaced.
4.11 Movement Joints Movement joints for expansion and contraction shall be constructed in accordance with the details and to the dimensions shown on the Drawings or where otherwise ordered by the S.O. and shall be formed of the elements specified. The Contractor shall pay particular attention to the effects of climatic extremes about the Works on any material which he may desire to use in any movement joint and shall submit for approval by the S.O. his proposals for the proper storage handling and use of the said materials having due regard for any recommendations in this connection made by manufacturers. Waterstops shall be incorporated into all expansion and contraction joints in units which retain or exclude liquids. Different types of waterstop material shall not be used together in any complete installation. Waterstops shall be fabricated into the longest practical units at the supplier's works and shall be continuous throughout the structure below highest water level. Intersections and joints shall be factory made where possible. Horizontally placed surface type waterstops shall have an interposing sliding plane.
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Section 4 - Formwork
Waterstops shall be carefully maintained in the position shown on the Drawings supported on accurately profiled stop boards to create rigid conditions. Joint filler shall be either cork joint filler or cellular joint filler. Cork joint filler shall be waterproof and rotproof and shall not extrude as a result of compression. Cork joint filler shall compress to less than 50% of its original thickness with immediate recovery to 80% or more of its original thickness. Cellular joint filler shall be a preformed low-compression joint filler made from foam rubber. Cellular joint filler shall recover to its original thickness after each loading and unloading. The joint filler shall be fixed to the required dimensions of the joint cross section and shall provide a firm base for the joint sealer. Where the depth of joint between the concrete surface and the water stop does not exceed 500mm a filler shall be placed in single depth sections. Sealing of movement joints shall be carried out only when adjacent concrete surfaces are perfectly dry. Immediately before the application of the joint sealer the groove protection batten shall be removed in such lengths as represent a single day’s work for sealing the joints. The joint grooves shall be cleaned, adequately primed and filled with approved sealer strictly in accordance with the manufacturer's instructions. On permanently exposed areas of structures joint sealing is to be carried out with the aid of masking tape to form neatly defined surface limits to the sealer.
4.12 Sliding Planes and Joints Sliding planes on the concrete blinding layer shall consist of building paper which shall be applied immediately before the structural floor is concreted and shall be at all times suitably protected. Where building paper is used the concrete surface shall be finished with a steel trowel to give a smooth surface. Sliding joints shall consist of one layer of bituminous felt, as BS 13707 Type IC of weight 1.36 kilogrammes per square metre, to each of the complementary contact surfaces. Alternatively, and subject to the approval of the S.O. sliding joints may comprise two layers of purpose made preformed plastic membrane which when in contact shall give a coefficient of friction of not more than 0.2 when subjected to a load of 270 kN/sq.m. Where formed in concrete structures the lower joint bedding surface shall be steel float finished to a smooth true surface.
4.13 Inspection and Testing Before concrete is placed against any formwork, the formwork shall be inspected and approved by the Contractor and offered for inspection by the S.O. If a "pour-card" system is in operation, the card shall be signed by the Contractor and submitted to the S.O. with the request for inspection of the formwork.
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Section 5 - Steel Reinforcement
5.0
STEEL REINFORCEMENT..........................................................................5-1 5.1
Scope ................................................................................................5-1
5.2
Submissions ....................................................................................5-1
5.3
Steel Reinforcement ........................................................................5-1
5.4
Steel Wires and Bars for Prestressing...........................................5-1
5.5
Accessories......................................................................................5-2
5.6
Detailing............................................................................................5-2
5.7
Cutting and Bending of Reinforcement .........................................5-2
5.8
Storage of Reinforcing Bars and Fabric ........................................5-2
5.9
Storage of Prestressing Wire and Bars .........................................5-2
5.10
Fixing of Reinforcement..................................................................5-2
5.11
Inspection and Testing....................................................................5-3
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Section 5 - Steel Reinforcement
5.0 STEEL REINFORCEMENT 5.1
Scope
This specification covers detailing, fabricating, supplying and placing of reinforcing steel and accessories for all cast in place and precast concrete.
5.2
Submissions
The following submissions are required to be submitted by the Contractor. (1)
Test certificates Manufacturer's test certificate for each delivery of reinforcing steel. Each certificate shall show the country of origin and test.
(2)
Data Manufacturer's data on accessories and mechanical couplings.
5.3
Steel Reinforcement
Steel for reinforcement shall be of the following kinds as may be specified or detailed on the Drawings: Type R
-
hot-rolled plain round mild steel bars conforming to BS 4449.
Type T
-
either, hot-rolled deformed high yield steel bars conforming to BS 4449 (with geometrical classification Type 2).
-
or, cold-rolled deformed high yield steel bars conforming to BS EN 10268 (with geometrical classification Type 2).
-
welded hard drawn steel wire and other cold worked high bond bar fabric conforming with BS 4483.
Fabric
5.4
Steel Wires and Bars for Prestressing
Prestressing steel wire or bars shall be of the following kinds as specified or detailed on the Drawings: (a)
Cold drawn wire or cold drawn and stress relieved wire conforming with BS 5896.
(b)
Stress relieved seven-wire strand conforming with BS 5896.
(c)
Stress relieved nineteen-wire strand confirming with BS EN10218-1.
(d)
Cold worked high tensile alloy steel bars conforming with BS 4486.
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Section 5 - Steel Reinforcement
5.5
Accessories
The Contractor shall supply all accessories such as reinforcing steel supports, hold-downs, spreaders, hangers, tie wire and all other incidentals necessary to complete an acceptable installation of all steel reinforcement. All accessories shall be of steel with the exception of spacers to maintain concrete cover to reinforcement against formed or blinded surfaces which shall be of concrete of same texture, colour and composition as cast-in-place concrete. Concrete spacers shall be in the form of a truncated cone or pyramid and shall be used with the larger face towards the reinforcing steel. The smaller face of a truncated cone or pyramid shall have a maximum dimension of 50mm.
5.6
Detailing
Steel reinforcement shall be as shown on the Drawings. The Contractor shall be responsible for checking the Drawings before cutting and bending reinforcement. When any information relating to reinforcement is missing or apparently incorrect, the Contractor shall advise the S.O. and remedy the missing or incorrect information to the approval of the S.O.
5.7 Cutting and Bending of Reinforcement Bars shall be cut and bent in accordance with the provisions of BS 8666 and BS EN ISO 3766. All bending shall be done cold with the use of an approved bending machine. Rebending of bars will not be permitted. Cut and bent bars shall be bundled and labelled for positive identification with the Drawings and bending schedules, until they are incorporated into the work.
5.8
Storage of Reinforcing Bars and Fabric
The Contractor shall stack separately and label different types of reinforcement for positive identification. Steel reinforcing bars shall be kept clean and shall be free from pitting, loose rust, mill scale, oil, grease, earth, paint, or any other material which may impair the bond between the concrete and the reinforcement. Reinforcing steel shall be stored and fabricated under cover on wooden or concrete supports such that the steel is elevated from the ground surface by a minimum of 150mm.
5.9
Storage of Prestressing Wire and Bars
In addition to complying with the above storage requirements, the Contractor shall ensure that prestressing wire and bars are protected from mechanical damage by storing on timber supports above a concrete slab, and shall ensure that during storage the wire and bars are kept properly coated with water soluble oil inside protective wrappings.
5.10 Fixing of Reinforcement
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Section 5 - Steel Reinforcement
All reinforcement shall be securely and accurately fixed in positions shown on the Drawings using approved spacer blocks or chairs. All intersections of bars shall be secured with No. 16 gauge (1.60mm) soft iron wire, the ends being turned into the body of the concrete. The Contractor shall ensure that all reinforcement is maintained in position at all times, particular care being taken during placing of concrete. Concrete cover to reinforcement shall be as specified or detailed on the Drawings, and shall be maintained in accordance with the tolerances specified in BS 8110. Correct concrete cover to reinforcement shall be maintained with the aid of approved spacer pieces. Top reinforcement in slabs shall be maintained in position by means of chairs, the diameter and quantity being sufficient to ensure security of the reinforcement in shape and position. No part of the reinforcement shall be used to support formwork, access ways, working platforms, or the placing equipment or for the conducting of an electric current.
5.11 Inspection and Testing When required by the S.O., the Contractor shall take samples from reinforcement delivered to site and shall arrange for the samples to be tested by an approved testing agency. Test certificates from that agency shall be submitted to the S.O. The S.O. or his authorised representative may require to witness such testing and also routine testing at the manufacturer's works. The Contractor shall be responsible for all checking and inspection of reinforcement before preparations for placing concrete are offered for inspection by the S.O.
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Section 6 - Piling
6.0
PILING .........................................................................................................6-1 6.1
General .............................................................................................6-1 6.1.1 Ground Conditions ...............................................................6-1 6.1.2 Setting Out.............................................................................6-1 6.1.3 Piling Equipment...................................................................6-2 6.1.4 Programme ............................................................................6-2 6.1.5 Pile Driving ............................................................................6-2 6.1.6 Trial and Working Piles ........................................................6-4 6.1.7 Load Tests .............................................................................6-4 6.1.8 Ultimate and Design (Working) Loads ................................6-4 6.1.9 Piling Personnel ....................................................................6-5 6.1.10 Piling Records .......................................................................6-5
6.2
Precast Reinforced Concrete Piles ................................................6-5 6.2.1 General...................................................................................6-5 6.2.2 Pile Casting ...........................................................................6-6 6.2.3 Curing, Stripping and Stacking............................................6-6 6.2.4 Handling Storage and Transport of Piles............................6-6 6.2.5 Pitching and Driving .............................................................6-7 6.2.6 Plant for Pile Driving.............................................................6-7 6.2.7 Measuring Pile Set ................................................................6-8 6.2.8 Extending Piles .....................................................................6-8 6.2.9 Preparation of Pile Heads.....................................................6-8 6.2.10 Load Tests .............................................................................6-8
6.3
Steel Sheet Piles ..............................................................................6-9 6.3.1 General...................................................................................6-9 6.3.2 Section and Properties .........................................................6-9 6.3.3 Storage and Protection.........................................................6-9 6.3.4 Piling Crew ..........................................................................6-10 6.3.5 Plant and Equipment ..........................................................6-10 6.3.6 Alignment of Sheet Piles ....................................................6-10 6.3.7 Lifting and Pitching.............................................................6-11 6.3.8 Pile Driving ..........................................................................6-11
6.4
Treated Timber Piles......................................................................6-11
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Section 6 - Piling
6.4.1 General.................................................................................6-11 6.4.2 Treatment of Piles ...............................................................6-12 6.4.3 Delivery and Stacking of Piles ...........................................6-12 6.4.4 Pile Driving and Jointing ....................................................6-12 6.4.5 Load Tests ...........................................................................6-13 6.5 Steel H-Piles..............................................................................................6-14 6.5.1 General.................................................................................6-14 6.5.2 Handling, Storage and Transport of Piles.........................6-14 6.5.3 Pitching and Driving ...........................................................6-14 6.5.4 Measuring Pile Set ..............................................................6-15 6.5.5 In-situ Lengthening of Piles ...............................................6-15 6.5.6 Welding ................................................................................6-15 6.5.7 Welding Personnel..............................................................6-16 6.5.8 Reuse of Cut-off Piles.........................................................6-16 6.5.9 Cutting of Pile Head ............................................................6-16 6.5.10 Load Tests ...........................................................................6-16 6.6
Prestressed Spun Concrete (PSC) Piles......................................6-17 6.6.1 Standard ..............................................................................6-17 6.6.2 Shape ...................................................................................6-18 6.6.3 Aggregates ..........................................................................6-18 6.6.4 Water ....................................................................................6-18 6.6.5 Cement.................................................................................6-18 6.6.6 Admixtures ..........................................................................6-18 6.6.7 Prestressing Steel...............................................................6-18 6.6.8 Reinforcement .....................................................................6-19 6.6.9 Reinforcement Details ........................................................6-19 6.6.10 Concrete ..............................................................................6-19 6.6.11 Curing ..................................................................................6-19 6.6.12 Level of Prestress ...............................................................6-19 6.6.13 Transfer of Prestress ..........................................................6-20 6.6.14 Pile Ends..............................................................................6-20 6.6.15 Manufacturing of Piles........................................................6-20 6.6.16 Splicing ................................................................................6-21 6.6.17 Marking of Piles...................................................................6-21
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Section 6 - Piling
6.6.18 Handling and Stacking .......................................................6-22 6.6.19 Joints ...................................................................................6-22 6.6.20 Welding of Joints ................................................................6-22 6.6.21 Tests for Approval of Welders ...........................................6-22 6.6.22 Examination of Welds.........................................................6-22 6.6.23 Driving Piles ........................................................................6-23 6.6.24 Pile Hammers ......................................................................6-23 6.6.25 Reduction of Hammer Energy............................................6-23 6.6.26 Pile Cushion Block..............................................................6-24 6.6.27 Driving..................................................................................6-24 6.6.28 Cutting Off and Capping Piles ...........................................6-24 6.6.29 Re-driving ............................................................................6-24 6.6.30 Jetting ..................................................................................6-24 6.6.31 Pile Shoes ............................................................................6-24 6.7
Cast-in-situ Bored Piles ................................................................6-25 6.7.1 Description ..........................................................................6-25 6.7.2 Workmanship ......................................................................6-25 6.7.3 Approval of Proposal..........................................................6-25 6.7.4 Shaft Diameter.....................................................................6-25 6.7.5 Length of Piles and Cut-off Level ......................................6-25 6.7.6 Pile Layout ...........................................................................6-25 6.7.7 Setting Out...........................................................................6-25 6.7.8 Equipment ...........................................................................6-26 6.7.9 Soil Information...................................................................6-26 6.7.10 Temporary Casings.............................................................6-26 6.7.11 Permanent Casing...............................................................6-26 6.7.12 Reinforcement .....................................................................6-26 6.7.13 Concrete ..............................................................................6-26 6.7.14 Supply of Drilling Fluids.....................................................6-26 6.7.15 Mixing of Drilling Fluids .....................................................6-26 6.7.16 Tests of Drilling Fluids .......................................................6-27 6.7.17 Setting Out...........................................................................6-27 6.7.18 Method of Boring ................................................................6-27 6.7.19 Use of Drilling Fluid for Stabilising Pile Borehole............6-28
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Section 6 - Piling
6.7.20 Spillage and Disposal .........................................................6-28 6.7.21 Boring Near Recently Cast Piles........................................6-28 6.7.22 Pumping from Pile Bores ...................................................6-28 6.7.23 Standard Penetration Test .................................................6-29 6.7.24 Proof Coring ........................................................................6-29 6.7.25 Depth of Bored Pile.............................................................6-29 6.7.26 Cleaning of Pile Bore ..........................................................6-29 6.7.27 Inspection of Pile Bore .......................................................6-29 6.7.28 Disposal of Spoil .................................................................6-30 6.7.29 Placing of Reinforcement...................................................6-30 6.7.30 Continuity of Construction.................................................6-30 6.7.31 Concreting - General...........................................................6-30 6.7.32 Workability of Concrete......................................................6-30 6.7.33 Minimum Cement Content..................................................6-30 6.7.34 Cube Tests...........................................................................6-31 6.7.35 Compaction .........................................................................6-31 6.7.36 Concreting in Dry Boring....................................................6-31 6.7.37 Concreting Under Water or Drilling Fluid .........................6-31 6.7.38 Extraction of Casing - General...........................................6-31 6.7.39 Workability of Concrete During Casing Extraction ..........6-32 6.7.40 Vibrating Extractor..............................................................6-32 6.7.41 Concrete Level ....................................................................6-32 6.7.42 Water Level ..........................................................................6-32 6.7.43 Preparation of Pile Heads...................................................6-33 6.7.44 Temporary Backfilling After Casting .................................6-33 6.7.45 Tolerances ...........................................................................6-33 6.7.46 Existing Services ................................................................6-33 6.7.47 Tidy Site ...............................................................................6-33 6.7.48 Public Safety........................................................................6-33 6.7.49 Daily Records ......................................................................6-33 6.7.50 Integrity Testing of Piles - General ....................................6-34 6.7.50.1 Shock Test .............................................................6-35 6.7.50.2 Sonic Logging Method..........................................6-35 6.7.50.3 Records .................................................................6-36 Typical Civil and Structural Engineering Specification for Sewerage Works Issue 01 / Rev 0 August 2008
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Section 6 - Piling
6.8
Micro Piles......................................................................................6-37 6.8.1 General.................................................................................6-37 6.8.2 Submission by the Contractor ...........................................6-37 6.8.3 Equipment ...........................................................................6-37 6.8.4 Materials ..............................................................................6-37 6.8.5 Method of Construction......................................................6-37 6.8.6 Grout Mix .............................................................................6-38 6.8.7 Rejected Micropiles ............................................................6-38
6.9
Pile Testing.....................................................................................6-38 6.9.1 General.................................................................................6-38 6.9.2 Test Load and Kentledge ...................................................6-38 6.9.3 Settlement Measurement....................................................6-39 6.9.4 Equipment and Personnel for Load Test ..........................6-39 6.9.5 Procedure of Testing ..........................................................6-39 6.9.6 Records of Test ...................................................................6-40 6.9.7 Interpretation of Test Results ............................................6-40
6.10
Rejection of Piles...........................................................................6-40
6.11
Dynamic Pile Load Test Method ...................................................6-41 6.11.1 General.................................................................................6-41 6.11.2 Measurements .....................................................................6-41 6.11.3 Field Data Processing.........................................................6-41 6.11.4 Measurement Devices ........................................................6-42 6.11.5 Hammer................................................................................6-42 6.11.6 Preparation of Pile Head.....................................................6-42 6.11.7 Personnel.............................................................................6-42 6.11.8 Preliminary Results.............................................................6-43 6.11.9 Detailed Report....................................................................6-43 6.11.10 Defective Piles...................................................................6-44
6.12
Piling Records................................................................................6-44
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Section 6 - Piling
6.0 PILING 6.1
General
Unless otherwise specified, all piling shall conform in all respects to the Civil Engineering Code of Practice BS 8004 `Foundations' issued by the `British Standards Institution, London'. The type of pile to be used at each structure, where piling is required, shall be as indicated on the Drawings or as directed by the S.O.
6.1.1 Ground Conditions Soil investigation including boreholes have been carried out by the Employer on the Site and the soil investigation report with borehole logs and samples are available for examination by the Contractor at the Employer’s office and the Contractor shall be deemed to have inspected them before preparing his tender. The results of the soil investigation are solely for the purpose of assisting the Contractor in the preparation of his tender. Neither the Employer nor the S.O. bears any responsibility for the correctness of the result. It shall be the Contractor’s responsibility to carry out further sub-surface investigation if he has any doubt about the available information or if he considers further information necessary or desirable. Such investigation by the Contractor shall be entirely at his own expense and shall have the Employer’s prior approval in writing. The S.O. shall be supplied free of charge with two (2) copies of the results of all such investigation by the Contractor. In addition to submitting the records required, the Contractor shall report immediately to the S.O. any circumstances which indicate that the ground conditions differ from those expected by the Contractor from his interpretation of the results of soil investigation carried out by the Employer and which affect adversely the bearing capacity of the pile or proposed foundation. The Contractor’s attention is, however, drawn to the fact that suitable founding strata may be encountered at depths which require the actual installation of different lengths of pile and which may give rise to considerable variation within any particular site or pile groups.
6.1.2 Setting Out The pile layout and the number of piles shown on the Drawings are provisional only. The Contractor shall, before commencing any part of the piling work ascertain from the finalised S.O. the layout of the piles required. The Contractor shall set out the piles from the main grid lines of the proposed structure or such base lines as shall be agreed with the S.O. The main setting out for piles shall be completed prior to commencement of piling. Secondary or individual pile setting out shall be completed and agreed with the S.O. not less than 24 hours prior to commencing work on the piles concerned. All main setting points, lines, stations and the like shall be suitably protected, maintained and undisturbed.
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Section 6 - Piling
For a pile cut-off at or above ground level the maximum permitted deviation of the pile centre from the centre point shown on the Drawings shall not exceed 75mm in any direction. For a pile cut off below ground level an increase in the verticality tolerance is permitted up to 1 in 75 from the finished pile.
6.1.3 Piling Equipment The piling equipment shall be capable of speedily and efficiently installing piles of the specified types, sizes, lengths and safe working loads. The type of piling equipment shall be suitable for the type of piles to be installed and shall be that of a system which produces minimum noise during pile installation. The Contractor shall provide sufficient number of units to ensure completion of piling work according to programme. Before any piling work is commenced, the Contractor shall submit to the S.O. full details of the pile driving equipment and the method of carrying out the work which he intends to use. Such information shall include a full description of the piling frame, hammer, helmet and packing and of a method of handling and pitching piles and supporting them during driving, and of the proposed driving procedure set to give penetration to the required level and of the proposed set for the working load on the pile and the method of calculating it. Any revisions to these proposals which, in the light of ensuing experience, appear desirable, shall also be submitted for the approval of the S.O. prior to implementation of said revisions. The piling frame shall be of sturdy construction, supported on an adjustable base, securely guyed and with ample toggle connections to leaders so that the pile is firmly held at all times. The type and weight of hammer shall be to the approval of the S.O. and the weight of the hammer shall be at least half that of the pile or otherwise specified. In general, a heavy hammer with a short drop should be used in preference to a light hammer with a longer drop. Single or double acting diesel or airoperated hammers may also be employed. The Contractor shall submit confirmation of hammer energy per blow to the satisfaction of the S.O. All plant being used shall be maintained in a satisfactory condition and any items suffering wastage or damage shall be promptly replaced or repaired. No piling shall be carried out without the approval in writing of the S.O. of the equipment and method of working and any revisions to these as described above, and the Contractor shall submit all of his proposals at least three weeks before the date on which he intends to use the plant on the Site.
6.1.4 Programme The Contractor shall submit to the S.O. his proposed programme for the execution of the piling work at least seven days before commencement of the work. In addition, the Contractor shall inform the S.O. daily of the programme of piling for the following working day and shall give adequate notice of his intention to work outside normal hours, if this has already been approved by the S.O.
6.1.5 Pile Driving Unless otherwise specified, pile driving shall be as specified hereunder.
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6-2
Section 6 - Piling
The driving equipment to be used shall be of such type and capacity to the approval of the S.O. If drop hammer is used, it shall be of a free fall type and the weight of the hammer shall be as specified in BS 8004. Piles shall be pitched accurately in the positions as shown on the Drawings or to the layout approved by the S.O. At all stages during driving and until the pile has set or driven to the required length, all exposed piles shall be adequately supported and restrained by means of leaders, trestles, temporary support or other guide arrangements to maintain position and alignment and to prevent buckling and damage to the piles. Each pile shall be driven continuously until the specified set and/or depth has been reached. However, the S.O. may permit the suspension of driving if he is satisfied that the rate of penetration prior to the cessation of driving will be substantially re-established on its resumption or if he is satisfied that the suspension of driving is beyond the control of the Contractor. A follower (long dolly) shall not be used for driving end bearing piles. It may be used for driving frictional piles with prior approval of the S.O. The Contractor shall inform the S.O. without delay if an unexpected change in driving characteristics is encountered. Where required by the S.O. set shall be taken at approved intervals during the driving to establish the behaviour of the piles. A set shall be taken only in the presence of the S.O. unless otherwise approved. The Contractor shall provide all facilities to enable the S.O. to check driving resistances. Redrive checks, if required, shall be carried out in accordance with an approved procedure. A detailed record of the driving resistance over the full length of each pile shall be kept. The log shall record the number of blows for every 300mm of pile penetration. The final set of a pile other than a friction pile, shall be recorded either as the penetration in millimetres per 10 blows or as the number of blows required to produce a penetration of 25mm. When a final set is being measured, the following requirements shall be met:(a)
The exposed part of the pile shall be in good condition, without damage or distortion;
(b)
The dolly packing shall be in sound condition;
(c)
The hammer blow shall be in line with the pile axis and the impact surfaces shall be flat and at right angle to the pile and hammer axis;
(d)
The hammer shall be in good condition and operating correctly;
(e)
The temporary compression of the pile shall be recorded if required.
Piles shall be driven in an approved sequence to minimise the detrimental effects of heave and lateral displacement of the ground. When required, levels and measurements shall be taken to determine the movement of the ground or any pile resulting from the driving process. If any pile rise occurs as a result of adjacent piles being
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driven, the Contractor shall submit to the S.O. his proposals for correcting this and to avoid the same in subsequent work.
6.1.6 Trial and Working Piles A trial pile is a pile installed at the Site before the commencement of the main piling work for the purpose of establishing the driving criteria for subsequent working piles and for confirming the adequacy of the pile design, dimensions and bearing capacity. This pile shall be treated as a working pile unless failure or excessive settlement has occurred. Trial piles shall be of the same materials and driven or formed with the same plant and in the same manner as the working piles. A working pile is a pile which is installed as part of the permanent foundation works. No work on working piles shall proceed until the testing of the trial pile has been completed to the satisfaction of the S.O.
6.1.7 Load Tests The Contractor shall submit to the S.O. for approval complete details of the testing equipment he intends to use for testing piles. All loading tests shall be carried out and comply with the conditions as described in Clause 6.9 of the Specification on pile testing. The S.O. will select the location of the trial test piles and the working piles to be load tested. The S.O. will decide upon the necessity for testing working piles, and may select for testing one or more working piles which the Contractor shall drive in advance of the remaining piles at the Site. Piles selected for this purpose shall be constructed or driven, with the same equipment as proposed for the main piling work, to the depths required by the S.O. The remaining piling at the Site shall not proceed until the testing of the advance working pile has been completed to the satisfaction of the S.O. and meets the requirements for acceptance specified herein. The S.O. will also instruct the testing of further piles during the course of the piling work.
6.1.8 Ultimate and Design (Working) Loads Where pile test is carried out the ultimate load is defined as the constant load at which the pile continues to settle at a steady rate or the load at which the maximum settlement of the pile top during one continuous loading cycle is one tenth of the pile base diameter or least dimension, whichever is the lesser. Where pile test is not carried out the ultimate load is defined as the calculated ultimate load, derived from appropriate static bearing capacity calculations. The design load or working load shall be defined in relation to a pile loaded in isolation, without nearby piles being loaded, except those providing test reaction. Where the ultimate load is not measured by means of pile tests, the design load is the lesser of the following:(a)
The calculated ultimate load for the pile divided by the specified factor of safety.
(b)
The calculated ultimate load of the pile base together with the calculated shaft adhesion, as derived from appropriate static bearing capacity calculations divided by a factor of safety of 3.0.
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Unless otherwise specified, the factor of safety shall be taken as not less than 2.0 for piles in compression and not less than 3.0 for piles in tension.
6.1.9 Piling Personnel Piling work shall be carried out under the direction of a competent supervisor experienced in the particular system of piling to be used. He shall be employed full time for the duration of the piling operations and his appointment shall be subject to the approval, in writing, of the S.O. before the commencement of piling work. The Contractor shall also employ at each site a specially qualified foreman together with the necessary gang of trained personnel and labour experienced in the installation of the piles.
6.1.10 Piling Records The Contractor shall keep a record of all piles installed at the Site. The record shall contain such details as specified or otherwise as required by the S.O. The Contractor shall also submit to the S.O. within 24 hours a copy of the field record of the piling work done each day. On completion of all piling work at each site, the Contractor shall prepare and submit to the S.O. two (2) complete sets of drawings showing details of all piles installed at the Site. All pile test records shall be considered as confidential and shall not be disclosed by the Contractor to any third party without the permission in writing of the Employer.
6.2
Precast Reinforced Concrete Piles
6.2.1 General Precast reinforced concrete piles shall conform to the details shown on the Drawings. Concrete reinforcement and formwork shall be in accordance with the appropriate Clause of the Specification. Main reinforcing bars shall be supplied in one complete length; should this prove impracticable separate lengths shall be effectively coupled mechanically or lapped as specified. Spacer forks shall be of cast iron, mild steel or other material or type and shape approved by the S.O. Pile shoes shall consist of "chill-hardened" cast iron points and mild steel straps cast into the points and be in accordance with the Drawings or otherwise approved by the S.O.
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6.2.2 Pile Casting Before any reinforced concrete pile is cast, the Contractor shall submit to the S.O. for approval a description, accompanied by Drawings and programme, of the methods he proposes to adopt for handling and driving piles, giving full particulars of all plant and equipment to be employed. Notwithstanding any approval of the Contractor’s proposals by the S.O., the Contractor shall be and remain solely responsible for the successful installation of the piles. The length of each pile unit cast shall be as detailed on the Drawings. Pile extensions shall be cast in suitable lengths to suit Site conditions. Where required, load tests shall be carried out to assess bearing capacity and estimate casting length. Pile units shall be cast in one continuous operation on a horizontal platform in steel or wooden moulds and no interruption shall be permitted. The moulds shall be thoroughly cleaned before casting, and the assembled reinforcement lowered into the mould and held in position from the top. Lifting holes shall be formed, during casting, in the position and in accordance with the details shown on the Drawings. The mild steel end plates for jointing piles and pile extensions shall be placed in the ends of the moulds before placing concrete. These plates shall be aligned with great care to ensure that they are truly perpendicular to the axis of the pile. Any pile or pile extension cast with an end plate not truly perpendicular to the axis of the pile shall immediately be rejected. After casting the piles, formwork shall be removed in the presence of the S.O. Failure by the Contractor to observe this requirement may result in rejection of the pile concerned. Any pile showing signs of honeycombing or other defects on removal of the formwork shall be repaired to the satisfaction of the S.O. before it is used in the Works.
6.2.3 Curing, Stripping and Stacking Piles made with ordinary Portland cement shall be kept damp for a period of 14 days after casting. Side forms may be stripped 4 days and bottom boards 12 days after casting, provided the piles are kept supported on level blocks spaced at not more than 1.8 m centres. After 21 days piles may be lifted and removed to a suitable stacking area but they may not be driven until they are at least 28 days. Each pile shall be clearly marked with the date of casting and all stacks shall be arranged to facilitate the removal of piles for driving in their correct order of age. For piles made with Rapid Hardening cement the above periods shall be modified as directed by the S.O.
6.2.4 Handling Storage and Transport of Piles Piles shall be handled with great care, lifted using only the proper lifting holes and supported in the manner as approved by the S.O. Any departure from the approved method of lifting the piles shall be approved by the S.O. before use. Piles shall be stored on adequate bearers so arranged that they may be picked up for transport without damage.
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Care shall be taken to ensure that bearers are level transversely so that piles are not subjected to undue stress. Handling and delivery of the piles shall be done in a manner which avoids excessive bending stresses. The method of transport shall be subject to the approval of the S.O. Any piles cracked or damaged during handling shall not be used in the Works and shall be replaced by the Contractor at no extra cost to the Employer.
6.2.5 Pitching and Driving Piles shall be pitched accurately in the positions and driven to the appropriate lines and levels shown on the Drawings. During and after completion of piling the pile head shall not be more than 75mm off centre in any one direction from its required position. Piles shall be suitably constrained to maintain their correct position by means of guys or guides but no piles which have been deflected from the permitted tolerance shall be forcibly brought back to correct alignment. Where piles are driven below the level of the bottom of the leads of the pile frame, extension leads shall be fitted. The use of a follower or dolly will not be permitted except with the written approval of the S.O. If a follower is permitted the dynamic stiffness of the follower must be equal to or higher than the dynamic stiffness of the pile. During driving the heads of the piles shall be protected by a helmet of cast steel or mild steel fitting closely around the pile. A packing of 25mm thick coiled hemp rope or other suitable material covering the head of the pile shall be contained within the helmet and separate the helmet from the head of the pile. The top of the helmet shall be recessed and fitted with a timber stub dolly 300mm long. The packing and stub dolly shall be renewed as often as necessary to prevent damage to the piles. The type of helmet specified above may be modified at the discretion of the S.O. Piles damaged during driving shall be removed and replaced by the Contractor without extra cost to the Employer unless the S.O. is satisfied that effective repairs can be made in-situ. The Contractor shall maintain a record of the driving of all piles giving sets and other details required by the S.O. to whom the records shall be submitted on request. All piles shall be driven to such final set or depth as may be approved by the S.O. Immediately after a pile has been completely driven, a record shall be made of the reduced level of the pile head and further checks shall be made on the level of the head after the driving of adjacent piles. Should any pile heave upwards it shall be redriven to its original level or, if necessary, until its specified set is again obtained.
6.2.6 Plant for Pile Driving If a gravity operated hammer is used the weight of the hammer shall be at least 3 tonnes or 75% of the weight of pile. If, however, conditions at the Site show that this is insufficient, the S.O. may require that a heavier hammer be used. Every hammer shall bear an identification mark and the Contractor shall furnish a weight bridge certificate of its actual weight. The hammer drop shall not exceed 1.5m and at no time during driving shall the centre of the hammer be more than 38mm off pile centre. If a single acting power operated hammer is used, the limitations on hammer weight specified above for gravity operated hammer shall apply to the moving weight of a single acting power operated hammer.
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If a double acting power operated hammer is used, the net energy per blow, multiplied by the efficiency of the blow shall be at least 25 kilojoules. If a hydraulic hammer is used the ram shall be raised by hydraulic fluid under high pressure to a predetermined height, and then shall allow to fall under gravity or force down onto the pile head. The basic ram weight shall be 3 tonnes and further 2 tonne segments can be added up to a total of 9 tonne. The drop height of the ram shall be between 0.2m and 1.2m with very close control of any specified height between these limits. The striking rate shall be controlled manually or is automatic. The striking rate shall be 40 blows/minute at 1.2m drop if automatic controlled is used.
6.2.7 Measuring Pile Set The Contractor shall provide suitable means of measuring and recording the pile set under each hammer blow. This may be achieved by using a fixed straight edge held against a sheet of paper affixed to the pile, and running a pencil along the straight edge at the moment of impact to record on the paper the elastic and plastic sets resulting from the blow. The straight edge shall be attached to a fixed frame of heavy timber standing close to the pile.
6.2.8 Extending Piles Piles shall be extended as directed by the S.O. and shall be carried out as described below. When the pile shall have been driven to within one metre of the pile head above ground level, the dolly and packing shall be removed and the head of the pile examined for damage. If the pile has suffered no damage, the end plate shall be thoroughly cleaned, free from rust and scale, and filed down to expose bare metal. The end plate of the pile extension shall be similarly cleaned and the extension pitched, placed carefully on top of the pile head, aligned and plumbed. The end plates shall then be joined by a fillet electric arc weld extending completely round all four sides as shown on the Drawings. After the slag has been chipped from the weld and the weld wire brushed and cleaned, it shall be inspected by the S.O. and, if pronounced satisfactory, it shall be painted with 2 coats of coal tar epoxy of an approved type. Pile driving shall continue when the paint has dried. If the pile head has suffered damage it shall be repaired by the Contractor to the satisfaction of the S.O. and the cost of all such repairs shall be borne by the Contractor.
6.2.9 Preparation of Pile Heads After pile driving and load tests have been completed to the satisfaction of the S.O., the top of each pile shall be cut down to the correct level, and the steel reinforcement exposed and bent into the required positions, prior to construction of the pile cap. Where the length of pile left above the required level exceeds the length of pile cap reinforcement required, the excess length of pile may first be cut at the level which provides the required length of reinforcement.
6.2.10 Load Tests The Contractor shall carry out load tests on precast concrete piles by the Maintained Load Method as detailed in Clause 6.9.
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Tests shall be carried out on trial piles and working piles, as defined in Clause 6.1.7 and as directed by the S.O.
6.3
Steel Sheet Piles
6.3.1 General The work comprises the supply, delivering and driving of steel sheet piles with matching corner and junction steel piles and the cutting of excess lengths of sheet piles all in accordance with the Drawings or as directed by the S.O. The Contractor shall provide all labour, plant, equipment, guide walings, timber trestles, temporary stores, and the like necessary for the execution of work and remove them on completion.
6.3.2 Section and Properties The steel sheet piles shall be `U' type with interlocking connection with one another to form a continuous watertight wall after driving. Special sections shall be used for all corners, junctions and at change of directions. Special sections shall be fabricated as instructed or of an approved rolled section. Each single pile shall have a minimum weight and section of modulus as described in the Drawings. The weight shall be exclusive of rolling margins, which shall not exceed 2.50% of the theoretical weight. The Contractor shall furnish manufacturer's certificates for sheet piles supplied by him as proof of the quality of steel for acceptance by the S.O. before any materials are brought to the Site. The S.O. may at his discretion, require additional tests to be made on samples taken from the Site. In the event of any steel sheet piles being found to be not in accordance with the relevant Standard the whole batch of steel piles from which the test samples are taken may be rejected by the S.O. and shall be removed from the Site at the Contractor’s own expenses, notwithstanding any previous acceptance on the strength of the manufacturer's certificates. The cost of all tests required by the Specification or the relevant British or other approved Standards shall be deemed to be included in the Contract Rates, except where specifically mentioned otherwise. Steel sheet piles may be purchased from different agents but shall be from the same rolling mill.
6.3.3 Storage and Protection Sheet piles supplied by the Contractor shall be transported, handled and stored on the Site in such a manner and location so as to prevent damage, distortion or corrosion. If in the opinion of the S.O., piles are damaged in the process of handling, storing and transporting, such that the structural value of such sheet piles are likely to be impaired, they shall be replaced as directed by the S.O. at the Contractor’s own expenses. When corrosion coating is specified, surfaces of steel sheet pile shall be suitably protected against corrosion by cleaning, priming and coating with high build coal tar epoxy. Surfaces shall be prepared
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to ISO 8501-1 Sa 2.5 by sand blasting or St 3 by mechanical means. Primer shall be compatible with the protective coating material. The coal tar epoxy shall be applied in three (3) coats to give a total finished dry film thickness of 400 microns.
6.3.4 Piling Crew The Contractor shall maintain on the Site a specially qualified experienced pile driving foreman, together with the necessary gangs of trained labour capable of carrying out the Works and dealing with all pile driving contingencies. The Contractor shall supply to the S.O. full description and particulars of the proposed driving crew and inspectors and such crew and/or inspectors shall be replaced, if the S.O. deems that they are not suitable for the works.
6.3.5 Plant and Equipment The Contractor shall provide and maintain all plant, equipment and vehicle, including frame-lifting and driving devices, temporary guide walings, supply of fuel and lubricants and other equipment necessary for execution and completion of the Works. Before commencement of piling, the Contractor shall submit to the S.O. full details of his working programme including the number and types of frames and hammers and/or rams which he intends to use and the S.O. reserves the right to order the Contractor, at no additional cost to the Employer, to provide any additional equipment and plant which the S.O. considers necessary for carrying out the Works. The S.O. may order the removal and/or replacement of any equipment and/or plant whenever he considers that such equipment and/or plant is not suitable for the Works. Notwithstanding any approval of the Contractor’s proposals by the S.O., the Contractor shall remain solely responsible for the successful and timely installation of the sheet piles. It shall be the responsibility of the Contractor to provide hammers of sufficient weight to control the drop so as to ensure that no piles are damaged during piling and that the piles are driven to the required penetration depth. In general, the pile hammer shall be adequately supported and located during driving. Hammer suspended from jib shall be fitted with proper guide attachments and hammer supported on frames shall be located to sit squarely on the piles at all times during driving and the frames shall be of a rigid and strong construction. The Contractor shall not remove any of his equipment or plant from the Site until the S.O. has certified in writing that all steel sheet piling has been satisfactorily completed.
6.3.6 Alignment of Sheet Piles Piles shall be driven in the positions indicated on the Drawings. The Contractor shall be responsible for the true and proper setting out of the piles and correctness of the position, levels, dimensions and alignments of all parts of the work and for the provision of all instruments, appliances and labour in connection therewith.
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The setting out and the checking of the correctness of position, levels, dimensions and alignments of the works shall be carried out by an experienced surveyor employed by the Contractor before commencing, during and after completion of piling work.
6.3.7 Lifting and Pitching Piles shall be lifted and pitched accurately to their positions shown on the Drawings. Where piles have been damaged due to improper handling, lifting and/or pitching, the Contractor shall replace the damaged piles at his own expense.
6.3.8 Pile Driving Sheet piles shall be pitched to form panels before driving. The piles shall be prevented from leaning and/or tilting and in this respect the Contractor shall allow for temporary guide walings, leg guides to the satisfaction of the S.O. Temporary guide walings, leg guides, back guides, and the like shall consist of substantial timbers and/or other approved materials spaced apart at a distance equal to the overall width of the piling with timber spacer blocks or other approved material to fit the profile of the piles. The piles shall be driven with the driving equipment suitable for the work. The heads of piles are to be protected by an approved type of helmet and dolly during driving and the hammer rope shall not be "snatched" before the hammer has completed it full drop. Driving of sheet pile shall commence by driving a pair of piles to part penetration and as vertical as possible. A minimum of ten piles are then interlocked and pitched ready for driving. The last pair of piles in the panels are driven to part penetration and the remaining pairs of piles are then driven to finished level in stages. The procedure shall then be repeated with a further panel of piles with the half driven last pair of the first panel forming the first pair of the second panel. Piles shall be driven in pairs or otherwise as directed. The interlock of the piles shall be lubricated with an approved grease. When driving, adjustments are to be made to compensate centres of sheet piling to fit into the overall length of sheet piling panels. Sheet piles shall be driven to the length and depth indicated on Drawings or as directed by the S.O. to achieve a satisfactory anchorage.
6.4
Treated Timber Piles
6.4.1 General Timber used for the piles shall not be of a lesser quality than the Selected Structural Grades specified in Clause J (Stress Grading) of Part III of the Malayan Grading Rules for Sawn Hardwood Timber. The timber shall be free from rot, fungal or pest attack and any other defects not permitted for its grade.
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The dimensions of sawn timber piles shall be within the range of 2mm less and 6mm greater than their specified cross-sectional dimensions. The centroid of any cross-section of a sawn timber piles shall not deviate by more than 25mm from the straight line connecting the centroids of the end faces of the standard length of pile. Where applicable the standard of workmanship shall conform to BS 5268. Before commencement of any work, the Contractor shall notify the S.O. the name of the supplier and manufacturer for approval. All piles supplied shall be SIRIM approved and bear the SIRIM acceptance logo. Piles shall be supplied in one single length of 6 metres, unless otherwise approved.
6.4.2 Treatment of Piles The method of treatment shall be the full-cell process as described in MS 3.38. The composition of preservative shall be Type 2 of MS 3.38. The depth of penetration of preservative when determined by the method described in Appendix H of MS 3.38 shall be a minimum of 25mm. The net dry salt retention in the treated part of the timber as determined by the method described in Appendix `K' of MS 3.38 shall be a minimum of 16 kg/m cu. The treated timber pile shall be permanently marked with identifications which indicate that it complies with the Specification, manufacturer trade mark, charge number and date of treatment, and the length of the pile. The S.O. may require inspection of the treatment plant to observe and ensure that the manufacturing process and control testings of the piles are carried out in accordance with the Specification. Records of the actual treatment schedule shall be kept during the treatment process, and the Contractor shall furnish such records for the piles supplied when requested by the S.O. Before the treated timber pile is accepted for the Works the Contractor shall obtain from the manufacturer of the treated piles a warranty on approved form which provides that for a ten year period the treated piles shall be free from such fungus and insect attack which may render the supported structures unsound.
6.4.3 Delivery and Stacking of Piles The Contractor shall notify the S.O. of the delivery of timber piles to the Site and provide the necessary facilities to enable the S.O to inspect the piles and take random sampling for determination of depth of penetration of preservative and the net dry salt retention. Accepted piles shall be marked and stacked in lengths on paving of drained hard ground. Each piece of pile shall be stacked clear of the ground and have an air space around it. The piles shall be separated by sticks or blocks placed vertically one above the other and closely spaced horizontally to avoid sagging of the piles. All rejected piles shall be removed from the Site promptly.
6.4.4 Pile Driving and Jointing The pile head shall be adequately protected during driving, so that "brooming" does not occur.
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The pile head shall be fitted with toothed metal plates as approved by the S.O. for protection against "brooming" and splitting during normal driving. In the case of hard driving, unless otherwise approved by the S.O., a metal helmet shall be fitted to the top of the pile. The top of the pile shall first be trimmed to fit closely into the recess of the underside of the helmet. A hardwood dolly and if necessary, a packing piece shall be used above the helmet. If during driving the head of the pile becomes excessively broomed or otherwise damaged, the damaged part shall be cut off, and the helmet refitted. Any pile driven to the required set at a depth of 6.0m or less shall be in one continuous length. If jointing is required, pile joints shall be made by using galvanised mild steel welded boxes 460mm long fabricated from 5mm thick plates unless otherwise shown on the Drawings. The internal dimensions of the box shall be 3mm undersized of the pile cross-section dimensions. The joint and the ends of the piles to be jointed shall be constructed, so that the necessary strength and stiffness are developed at the joint. When fissures appear in a pile during driving, which in the opinion of the S.O. will affect its strength, the pile shall be rejected and replaced at the Contractor’s expense. When a pile has been driven to the required set or depth, the head of the piles shall be cut off square to sound wood and treated with an approved preservative and a waterproof coating to the approval of the S.O. The pile head shall be embedded for a depth of not less than 50mm in the pile cap.
6.4.5 Load Tests The Contractor shall carry out load tests on treated timber piles by the Maintained Load Method as detailed in Section 6.9. Tests shall be carried out on trial piles and working piles, as defined in Section 6.1.7 and as directed by the S.O.
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6.5
Steel H-Piles
6.5.1 General Steel H-piles shall comply with the requirements of BS 7668 Grade 43A and shall be of the dimensions shown on the Drawings or in the Bills of Quantities. They shall be supplied in 12m minimum lengths. The Contractor shall submit copies of manufacturer's test certificates in respect of the materials to be used in fabricating of the piles. Where the source of supply of the material is changed, fresh test certificates shall be submitted. The piles shall not deviate from straightness by more than 1/600 of any complete pile length measured at the centre of that length. Each pile shall be marked indelibly to show its identification number and length.
6.5.2 Handling, Storage and Transport of Piles The Contractor shall exercise greatest care in the handling of the piles during loading, transporting, unloading and stacking. Piles shall be lifted only by use of suitable fittings attached through lifting holes. The use of slings round the piles will not be permitted. The piles shall be handled, transported and stored on timber platforms resting on unyielding ground so as to prevent undue distortion and undue stress on the piles. Any pile damaged during handling, transporting and storage shall be replaced or repaired (if permitted by the S.O.) by the Contractor at his own cost.
6.5.3 Pitching and Driving Piles shall be pitched accurately and driven to positions shown on the Drawings or as directed by the S.O. During and after completion of piling, the pile head shall not be more than 75mm off centre in any one direction from its required position. Piles deflected from the intended line with an eccentricity larger than this shall, where ordered by the S.O., be withdrawn and repitched until the proper line is obtained. No forcible method of correction will be permitted. During driving the pile head shall be protected by a mild steel helmet, fitted closely around the top of the pile. Piles shall be driven using a drop hammer raised either by winch or internal pressure. Air or diesel operated hammers may also be used. The piles shall be driven to the depths shown on the Drawings or to such final set or depths as may be required by the S.O. Any pile which has arisen as a result of driving adjacent piles shall be redriven to its original level or its specified set, unless otherwise directed by the S.O. Any holes left by the withdrawal of piles shall be filled with an approved non-plastic material before re-driving. Piles damaged during pitching or driving shall be removed and replaced. Any remedial means and effective repairs to piles with the S.O.’s approval shall be at the Contractor’s own cost.
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6.5.4 Measuring Pile Set The Contractor shall provide suitable means of measuring and recording the pile set under each hammer blow. This may be achieved by using a fixed straight edge held against a sheet of paper affixed to the pile, and running a pencil along the straight edge at the moment of impact to record on the paper the elastic and plastic sets resulting from the blow. The straight edge shall be attached to a fixed frame of heavy timber standing close to the pile.
6.5.5 In-situ Lengthening of Piles Where it becomes necessary to splice or lengthen a pile, the top of the pile and the bottom of the extension pile shall be prepared for manual Vee butt and fillet welding by metal arc welding process. Suitable means shall be employed to ensure straightness of the spliced or lengthened piles. After each pile has been lengthened or spliced and prior to further driving the Contractor shall clean the pile at the joint and paint the surface with a suitable primer followed by two coats of coal tar epoxy paint or equivalent. Pile driving shall continue only when the coating has hardened.
6.5.6 Welding All electric arc welding equipment shall be to the approval of the S.O. and shall comply with BS EN ISO 2560 applicable to welding of piles rolled from steel manufactured to BS 7668 Grade 43A. All welding electrodes shall comply with BS EN ISO 2560 applicable to welding of Grade 43A steel. The Contractor shall also comply with the requirements of BS EN 1011-1 including stress relief for welding of high tensile steel and shall submit details of the welding procedure which he proposes to adopt for the S.O.’s approval, including: (a)
Make, type and gauge of electrodes
(b)
Size, shape and number of runs in weld joint
(c)
Direction of welding
(d)
Welding current
(e)
Length of run per metre of electrode
Only procedures approved in writing by the S.O. shall be adopted in welding on the steel piles. Welding shall be carried out in accordance with the details shown on the Drawings. The portion of the piles to be welded shall be cleaned to a bright metallic finish before welding. The weld shall be of the complete full penetration butt weld and convex full fillet type. Welds shall be subject to inspection by the S.O. and shall comply with the requirements for fusion, penetration, soundness and freedom from undercutting.
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6.5.7 Welding Personnel Only the most highly skilled welders shall be employed on the works and every welder before commencing any joint welding shall prepare specimens for testing in accordance with API Standard 1104 or similar for each welding procedure proposed by the Contractor. The S.O. will advise the Contractor in writing which welders pass the performance qualification test. Only these welders will be allowed to joint steel piles. The S.O. shall be at liberty to withdraw his approval of any welder responsible for making joints which fail to meet the required standard.
6.5.8 Reuse of Cut-off Piles Cut-off piles may be reused for the Works provided: (a)
The cut-off piles are of good condition and not less than 4 metres long.
(b)
When used to make up full length piles or extension piles there will be no extra costs for spliced joints required for the make-up pile.
(c)
Such make-up piles shall be used only in locations to the direction of the S.O.
6.5.9 Cutting of Pile Head After the pile has been driven to the required level and set, the pile shall be cut, if required, to the finished level as shown on the Drawings and to the satisfaction of the S.O.
6.5.10 Load Tests The Contractor shall carry out static load tests on piles as directed by the S.O. The loading platform shall be strongly built and suitable arrangements made to prevent over-turning. The load shall be applied so that its magnitude can be determined accurately. Concrete or metal blocks, bags of sand, structural steel or water in a tank may serve this purpose. The test piles shall be selected by the S.O. The pile selected for testing may form part of the foundation to the structure. Piles selected by the S.O. shall be tested by the Contractor as follows: (i)
The test load shall be applied using a jack by a method approved by the S.O. and shall be measured within an accuracy of 2%. Settlement recovery shall be measured within an accuracy of 0.05mm from a datum that will not itself be affected by any movement of the ground due to the test loading or other causes. The S.O. may require independent checks on the level of the datum by an accurate levelling instrument.
(ii)
The jack shall be properly calibrated by an approved testing station and the appropriate certificate produced before any tests commence. The measuring equipment and supports employed shall be adequately protected from the sun and elements and the readings of the air temperature shall be made and recorded at the same time as those on the gauges of the several measuring instruments used.
(iii)
The test load shall be applied in equal increments of one-tenth of the working load up to the working load and thereafter at 20% of the working load up to twice the working load.
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(iv)
The load shall be kept constant after each increment or reduction until the rate of settlement does not exceed 0.25mm per hour.
(v)
The load shall be applied and removed gradually and without shock. Other work that might cause vibration or any other disturbance to the ground conditions at the test site or affect the plant or apparatus being used in the test shall be suspended during the period of the test.
(vi)
The safe working load shall be maintained for at least 12 hours and the full test load of 2 times the working load shall be maintained until the rate of settlement ceases to be apparent but for not less than 48 hours.
(vii)
The amount of settlement and recovery shall be read and recorded immediately after the change of loading and at 10 minute intervals thereafter. Readings under working load, full test load and during recovery at zero load need not be taken and recorded more frequently than at 1 hour intervals.
(vii)
The Contractor shall, within 48 hours of the completion of the test, submit to the S.O. for each pile tested a detailed record of testing together with graphs prepared to suitable scale, showing:
(viii)
6.6
(a)
load and settlement plotted above and below a common base line of time;
(b)
settlement and recovery plotted vertically against a base line of load.
For acceptance, the settlement of the pile under the test load and the recovery of the pile after their subsequent removal of the test load shall not exceed the following values: (a)
residual settlement
-
6mm
(b)
settlement under working load
-
12mm
(c)
settlement under twice the working load
-
38mm
Prestressed Spun Concrete (PSC) Piles
6.6.1 Standard Piles shall be manufactured to comply with the requirements of: -
BS 8004
:
British Standard Code of Practice for Foundation
-
BS 8110
:
Standard use of concrete
-
BS 5400 Part 7 :
Specification for materials and workmanship, concrete, reinforcement and prestressing tendons
-
BS 5400 Part 8 :
Recommendation for materials and workmanship, concrete, reinforcement and prestressing tendons.
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6.6.2 Shape The PSC piles shall be made of hollow cylinders of external diameter with a wall thickness sufficient to support the working loads indicated on the drawings. They shall be provided with an appropriate steel joint which will have the same performance as the main body. The external diameter and thickness of the hollow cylinder shall be constant over the entire length of the pile and coaxial with the steel casing at each end.
6.6.3 Aggregates Coarse aggregates shall be clean granite and shall not contain any deleterious materials, dust, mud, salts or organic matter other requirement of BS EN 12620. The maximum size of the coarse aggregate shall be less than 20mm, and shall be less than 2/5 of the thickness of the PSC piles. Fine aggregates shall be clean river sand. Sea or beach sand shall not be used.
6.6.4 Water The water shall be free of oil, acid, salts, organic matter or other substances that be deleterious to concrete or steel and shall conform to the requirement of BS EN 1008.
6.6.5 Cement Shall be ordinary Portland cement meeting the requirement of BS EN 197 - 1.
6.6.6 Admixtures Admixtures shall be such as not to produce any defects to the concrete and/or to the reinforcement. Calcium chloride shall not be used. Admixtures permitted to be used shall meet the requirement of BS 5057.
6.6.7 Prestressing Steel (a)
General
Wires or bars shall be free from grease or other materials likely to impair the bond. The steel should not be pitted. (b)
Materials
The prestressing steel should be one of the following: (i)
Plain hard-drawn steel wire complying with the requirements of BS 2691, "Steel for Prestressed Concrete Part 1 Plain Hard-drawn Steel Wire".
(ii)
Indented or crimped hard-drawn steel wire complying with the requirements of BS 2691 in all respects except for the bend test.
(iii)
High tensile steel bars of open hearth steel with sulphur and phosphorus contents each below 0.05 per cent. Bars whether plain or deformed should have a tensile strength of not less than 930MPa with a 0.25 per cent proof stress of not less than 75 per cent or more than 92
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per cent of the actual ultimate strength. Methods of testing shall be in accordance to BS 10002 - 1, "Tensile Testing of Metals". (iv)
Such other wires, strand or bars having properties not inferior to those laid down in BS 2540 in sub-clause (iii) above respectively.
6.6.8 Reinforcement Steel reinforcement should comply with the requirements of BS 8110 "Structural Use of Concrete".
6.6.9 Reinforcement Details The total sectional area of prestressing tendons and axial reinforcement arranged in a straight axial direction shall not be less than 1%. The net space between the prestressing tendons and the axial reinforcement shall be more than the larger of their diameters and more than 4/3 of the maximum size of the coarse aggregate. The spiral and ring reinforcement shall be arranged on the outside of the prestressing steel and axial reinforcement. Such spiral and ring reinforcement shall be more than 3mm in diameter and shall have a pitch no greater than 150mm. The cover shall be not less than 30mm. The prestressing steel and reinforcement shall be free of loose rust or any material which will reduce bond.
6.6.10 Concrete The 150mm x 150mm test cube strength of the concrete for the manufacture of the PSC piles shall not be less than 78.5MPa at 28 days.
6.6.11 Curing The PSC piles shall be cured under moist conditions for at least 6 days after they have been removed from the moulds. If steam curing is used, the curing period may be reduced to 3 days. When low pressure steam curing is performed, the following requirements must be complied with: (a)
Steam shall be introduced so that the temperature in the curing chamber is raised uniformly.
(b)
Steam curing shall not be performed until at least two hours have elapsed after the mixing of the concrete.
(c)
The rate at which the temperature in the curing chamber is raised shall not be greater than 20oC per hour and the maximum temperature shall not be greater than 70oC.
(d)
The piles shall be taken out of the curing chamber only after the temperature in curing chamber has been gradually reduced to that prevailing outside.
6.6.12 Level of Prestress The prestress after allowing for losses should satisfy the following conditions:
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(a)
Prestress to cover handling, transporting and lifting conditions, for this purpose it may be assumed that only 75% of the full loss of prestress will have occurred within 2 months of a casting.
(b)
Prestress in kgf/cm of not less than 0.7 times the ratio of the length of the pile to its least lateral dimension, and not less than 50kgf/cm.
(c)
Minimum prestress related to the ratio of effective weight of hammer to weight of pile to be in accordance to BS 8004.
6.6.13 Transfer of Prestress The transfer of prestress shall be in accordance with BS 8004.
6.6.14 Pile Ends Both ends of each length of pile are to be provided with a casing made from steel plate of at least 16mm thickness. The ends of the prestressing tendons shall be fixed to the steel casing such that the full prestressing force shall be flush with the top plate of the steel casing. The end surface of the steel casing shall be in a plane which is at right angles to the longitudinal axis of the pile. The barrel of the steel casing shall be flush with the barrel of the concrete shaft of the PSC pile, with a chamber to accommodate the welding when two lengths of pile are jointed.
6.6.15 Manufacturing of Piles Piles shall be manufactured by the centrifugal casting process. Metal forms shall be used and they shall be well braced and stiffened against deformations caused by the hydrostatic pressure of the wet concrete while spinning. The metal forms shall have smooth joints and inside surfaces. The forms shall be accessible for adequate cleaning. The portions of the forms which form the end surfaces of the pile sections must be a true plane perpendicular to the axis of the section within the following tolerances: maximum allowable deviation of 1.5mm for abutting end surfaces, 5mm for pile head end surfaces and 25mm for pile tip end surfaces. The concrete mix shall provide the most uniform possible distribution of aggregates across the wall of the pile sections. Fine and coarse aggregates shall have as nearly as possible the same specific gravity. The water ratio by weight shall not exceed 0.35. The concrete shall be Grade 78.5 (in conformance to BS 5400: Part 7) and have a minimum compressive strength of 78.5MPa at twentyeight (28) days.
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The wall thickness of the spun pile shall be within the following tolerance: - 3mm, +9mm Pretension reinforcing wires shall be centred in the pile wall. The transfer of prestress shall be in accordance with BS 8004. The spiral reinforcement shall be wrapped outside the longitudinal reinforcement and shall have the minimum cover as required in the Codes. The spiral cage shall be securely held in position during the casting and spinning operation. The piles may be initially steam cured. Steam shall not be applied until 60 minutes have elapsed following casting. The section may then be steam cured between 55oC and 70oC. Steam shall be so introduced that the temperature in the curing chamber is raised uniformly. After the section has been steam cured for a minimum of (3) hours, the forms may, if the concrete has reached sufficient strength to sustain all handling stresses, be removed from the section. The pile shall not be taken out of the curing chamber until the temperature in the curing chamber has been gradually reduced to the prevailing temperature outside. The curing shall be carried out by such a method that may not affect adversely the quality of the product. The method of handling of the pile sections shall be such that no damage to the concrete will occur. However, the minimum prestress in the concrete after all losses shall be adequate to resist stresses induced by handling. The main body of the prestressed concrete pile shall, when subjected to the bending test, not develop crack of width more than 0.05mm under a bending moment as specified. The bending strength test shall be performed by supporting the pile section at points located 1/5L from its ends (where L is the length of the pile section). The vertical load shall be applied at the centre of the span. Two piles from each lot shall be so tested. If one of the two does not meet the test criteria, four other pile sections shall be further sampled and tested. If all four satisfy the test, then all piles in the lot will be accepted; otherwise all piles in that lot shall be rejected. Both ends of each length of pile are to be provided with a steel end plate. The ends of the PC tendons shall be fixed to the steel end plate such that the full prestressing force is transmitted over to the steel end plate. The ends of the PC tendons shall be flushed with the top of the steel end plate. The end surface of the steel end plate shall be in plane which is at right angles to the longitudinal axis of the pile. The barrel of the steel casing welded to the end plate shall be flushed with the barrel of the concrete shaft of the pile, with a chamber to accommodate the required depth of welding when two lengths of pile are jointed.
6.6.16 Splicing When two lengths of pile are joined, the end plates must bear over their complete areas. Shims for packing will not be accepted. The two end plates are to be welded around their entire periphery.
6.6.17 Marking of Piles
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Each pile shall have marked on its side, within 300m from the head, the length of pile, the date of casting, and identification number. The marking shall be in indelible paint which is not injurious to the concrete and the letters shall be at least 75mm high. In addition the pile shall be marked by indelible paint as above perpendicular to its lengths commencing at 5 metres from the toe at every 200mm up to the head. Just above each line, i.e. on the side further from the toe, the distance of each such line from the toe shall be painted.
6.6.18 Handling and Stacking Prestressed piles shall not be lifted or handled until fully stressed. Piles shall be lifted, supported and pitched at the positions indicated by the manufacturer. For the stacking of piles, heavy sill logs shall be well bedded on the ground or on a prepared surface, and shall be flattened to give a bearing width not less than 200mm, and a minimum clearance of 300mm above ground. Piles may be stacked on top of each other up to six layers. Each layer shall be separated from the next layer by timber bearers, each 100mm wide and 75mm high. The bearers shall be placed centrally above the sill logs, and above one another, so that no additional bending in any pile in the stack.
6.6.19 Joints The bending strength of a joint between two lengths of pile shall be equal or more than the bending strength of the concrete shaft. When two lengths of pile are jointed, the end plates must bear over their complete areas. Shims for packing will not be accepted. The two end plates are then welded along their entire periphery with weld size as specified in the drawing or where not shown in drawing, to the requirements of the pile manufacturer.
6.6.20 Welding of Joints All welding shall be carried out in accordance with requirements of BS EN 1011: Metal-Arc Welding of carbon and carbon-manganese steel. The Contractor shall supply the S.O. with full details of his proposed method of welding and shall if required, arrange for a demonstration, and the Contractor shall employ not less than two teams of welders.
6.6.21 Tests for Approval of Welders Welders shall be qualified in accordance with the requirements of AWS (American Welding Society) Code D1.1. Only welders who pass the qualifying tests for the type of weld shall be employed on the Works.
6.6.22 Examination of Welds Fillet welds between the end plates of the joints shall be tested using magnetic particle or dye penetrant test methods. Copies of these test records and reports shall be furnished to the S.O. Where such examination reveals defects in the welds, the joints shall either be rejected or repaired. If repeat tests show the weld to be still defective, the joint shall be rejected. The defective weld shall be removed, replaced with a fresh weld, and re-examined.
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For the purpose of this Clause, cracks, leaks, laminations, lack of complete fusion, undercutting or reduction in wall thickness adjacent to the weld shall constitute a defect.
6.6.23 Driving Piles The Contractor shall submit full details of his proposed pile driving equipment and methods to the S.O. for approval before commencing pile driving operations. Each pile shall be driven continuously until the specified set and/or depth has been reached. However, the S.O. may permit the suspension of driving if he is satisfied that the rate of penetration prior to the cessation of driving will be substantially re-established on its resumption or if he is satisfied that the suspension of driving is beyond the control of the Contractor. The follower (long dolly) shall not be used without prior written approval from the S.O. If use of the follower is permitted by the S.O., its dynamic stiffness must be at least as large as the dynamic stiffness of the pile. The Contractor shall take every precaution in pitching and driving or sinking the piles to ensure that no damage occurs to them and that they are pitched and driven sunk in the positions shown on the drawings. The piles shall be driven down or sunk to such depths as to be capable of carrying the specified loads.
6.6.24 Pile Hammers Pile hammers shall be of size and type able to deliver consistently and effective dynamic energy suitable to the piles to be driven and the material into which they are to be driven. Hammers shall be provided with proper driving helmets suited for the piles. Any indication of collapse of hoses, stripping of hose lining or any erratic action of the hammer shall be cause for immediate shutdown until the problem has been corrected. Pile hammers shall be operated at the full rated efficiency and capacity and in the manner specified by the manufacturer, except as directed otherwise by the S.O., or noted herein below under reduction of Hammer Energy. When a steam or air hammer is used for driving any type of piles, both the volume and pressure of steam or air recommended by the manufacturer of the hammer shall be maintained at all times to ensure full energy of the driving blows. Before the pile driving is started, the Contractor shall provide written certification to the S.O. that the pile hammer, compressors and valves have been inspected and found to be in good working condition.
6.6.25 Reduction of Hammer Energy When the pile is set in a pre-jetted or pre-drilled hole or when the point of a prestressed concrete pile is passing through soft soil so that there is little or no resistance to penetration of the pile, there is a possibility that longitudinal tensile stresses may be set-up in the pile shaft by the elastic shock waves travelling up and down the pile. For such driving conditions, the length of stroke of the hammer shall be reduced. Failure of the piles due to longitudinal tensile stresses caused by excessive driving shall be the Contractor’s responsibility.
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6.6.26 Pile Cushion Block The heads of all prestressed concrete cylinder piles shall be protected with a soft wood cushion block at least 15cm thick to effectively and uniformly distribute hammer blow energy. The block shall be composed of layers of 25mm plywood or approved equivalent, and of such dimensions as to completely cover the concrete cross-section of the pile. The cushion block shall be inspected periodically during driving and no driving shall be done with a block that has been unduly worn and compressed with use. Cushion blocks must be replaced when compressed to 1/2 their original thickness, when badly worn or when burning.
6.6.27 Driving The piles shall be driven to the driving resistance or tip elevation as determined by the S.O. from pile load tests. The maximum allowable variation at the butt end of the pile shall be 150mm in any direction from the location shown on the Drawings or as directed by the S.O.
6.6.28 Cutting Off and Capping Piles Top of foundation piles shall be embedded in the concrete footing or pile cap, a minimum depth of 75mm (measured at centre line of pile). When the top elevation of a pile is below the elevation of the bottom of the cap, the pile shall, if approved by the S.O., be built-up from the butt of the pile to the elevation of the bottom of the cap by an approved method. The cuts shall be made accurately in clean, straight line; care shall be exercised to avoid damaging the remaining pile and to ensure full bearing between the footings (or caps) and piles. The inside of the pile shall be roughened (by sand blasting or bush hammering) in order to improve the bonding strength between the cast-in-situ concrete cap and the precast concrete pile. The cast-in-situ concrete cap shall not be poured until the inside of the precast pile has been inspected by the S.O. and his approval is obtained.
6.6.29 Re-driving Re-drive checks, if required, shall be carried out in accordance with an approved procedure.
6.6.30 Jetting Jetting shall be carried out only when the Contractor’s detailed proposal have been approved.
6.6.31 Pile Shoes Pile shoes of a type which seal off the core shall not be used on spun concrete piles.
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6.7
Cast-in-situ Bored Piles
6.7.1 Description This Clause gives the requirements for the installation and testing of bored piles. This work shall comprise the boring or grabbing, with or without casing, and subsequently filling the hole with plain or reinforced concrete to form bored cast-in-situ piles, all in accordance with this Specification and to the details shown on the Drawings.
6.7.2 Workmanship All materials and workmanship shall be in accordance with the appropriate current British Standards or Codes of Practice except where the requirements of the British Standards/Codes of Practice are in conflict with this Specification in which case the content of this Specification shall take precedence.
6.7.3 Approval of Proposal Before any piles are installed, the Contractor shall submit to the S.O. for approval the description of the method he proposes to adopt for installing the bored piles giving full particulars of the drilling and the plant and equipment to be employed. Notwithstanding the approval of the Contractor’s proposals by the S.O., the Contractor shall be and remain solely responsible for the successful installation of the piles.
6.7.4 Shaft Diameter The diameter of the shaft shall not be less than the specified designed diameter as shown in the Drawings, at any level throughout its length. Temporary casing used to control the shaft diameter shall have a nominal inner diameter 25mm greater than the required shaft diameter.
6.7.5 Length of Piles and Cut-off Level The cut-off level of piles shall be as shown in the Drawings. The lengths of piles shown in the Drawing are indicative. The actual length of pile shall be decided by the S.O. based on examination of the material recovered from the pile excavation, results of in-situ test at the bottom of the pile excavation and the results of preliminary pile load tests.
6.7.6 Pile Layout The pile layout and the number of piles required are as shown in the Drawings. If necessary inclined piles have to be provided with a ratio of 1 : 10 or 1 : 8 or 1 : 6 maximum.
6.7.7 Setting Out Setting out shall be carried out using the data and reference points as shown on the Drawings. Immediately before installation of the pile, the pile position shall be marked with suitable identifiable pins, pegs or markers.
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6.7.8 Equipment The Contractor shall provide all plant, tools appliances and temporary works required for the installation of bored piles. All plant, materials and methods employed in the formation of the piles shall be such as to ensure that the completed piles are of the desired cross sections.
6.7.9 Soil Information The Contractor shall, prior to starting the work, satisfy himself of the adequacy and accuracy of the information contained in available soil reports by such additional borings and other tests as he may deem necessary.
6.7.10 Temporary Casings Temporary casing shall be of appropriate size and of approved quality. They shall be free from significant distortion and shall have sufficient strength to withstand handling stresses and external pressures of the caving soil or water. They shall be of uniform cross section through out each continuous length and shall be free from internal projections and encrusted concrete and lumps of soil which might prevent the proper formation of the pile.
6.7.11 Permanent Casing Permanent casings, if required as part of the designed pile shall be as specified or shown in the Drawings.
6.7.12 Reinforcement The reinforcement shall be as specified in Section 5.
6.7.13 Concrete Materials for concrete shall be as specified in Section 3. Where ready-mixed concrete is used, with the approval of the S.O., it should be in accordance with BS 8500.
6.7.14 Supply of Drilling Fluids Drilling fluid shall be bentonite suspension and shall be of approved quality and shall comply with the specification No. DF CP4 of the Oil Companies Materials Association, London (Drilling Fluid Materials - Bentonite). A certificate shall be obtained by the Contractor from the manufacturer of the bentonite powder, showing the properties of each consignment delivered to site. This certificate shall be made available to the S.O. on request.
6.7.15 Mixing of Drilling Fluids Bentonite shall be mixed thoroughly with clean fresh water to make a suspension which will maintain the stability of the pile excavation for the period necessary to place concrete on completion of the excavation. Preparation of the suspension shall comply with the manufacturer's instructions. Where saline or chemically contaminated groundwater occurs, special precautions shall be taken to modify the bentonite suspension or prehydrate the bentonite in fresh water so as to render it suitable in all respects for the construction of piles.
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6.7.16 Tests of Drilling Fluids The frequency of testing drilling fluid and the method and procedure of sampling shall be proposed by the Contractor prior to the commencement of the work. The frequency may subsequently be varied as required, depending on the consistency of the results obtained. Control tests shall be carried out on the bentonite suspension, using suitable apparatus. The density of freshly mixed bentonite suspension shall be measured daily as a check on the quality of the suspension being formed. The measuring device shall be calibrated to read to within 0.005g/ml. Tests to determine density, viscosity, shear strength and pH value shall be applied to bentonite supplied to the pile boring and the results shall generally be within the ranges stated in table below. The tests shall be carried out until a consistent working pattern has been established, account being taken of the mixing process, any blending of freshly mixed bentonite suspension and previously used bentonite suspension and any process which may be used to remove impurities from previously used bentonite suspension. When the results show consistent behaviour, the tests for shear strength and pH value may be discontinued, and tests to determine density and viscosity shall be carried out as agreed with the S.O. In the event of a change in the established working pattern, tests for shear strength and pH value shall be reintroduced for a period if required. Property to be Measured
*
Range of Results at 20oC
Test method
Density
Less than 1.10g/ml
Mud Density Balance
Viscosity
30-90s or
Mash Cone Method
Less than 20cP
Fann Viscometer
Shear Strength (10 minute gel strength)
1.4 - 10N/mm2 or 4-40N/mm2
Shearometer Fann Viscometer
pH
9.5 – 12
pH indicator Paper Strips or Electrical pH Meter
Where the Fann viscometer is specified, the fluid sample should be screened by number 52 sieve (300μm) prior to testing.
6.7.17Setting Out The Contractor shall check the position of each pile during and immediately after placing the casing and it shall be checked and approved by the S.O. before the boring starts.
6.7.18 Method of Boring Boring shall be carried down to the depth as required and as directed by the S.O. The boring shall be carried out by power auger. Where caving conditions are encountered or where excess water begins
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seeping into the borehole, no further drilling shall take place until the Contractor takes all necessary precaution and selects an approved method of preventing the ground movements or ingress of water or foreign material. Where instructed by the S.O., the Contractor shall place a temporary casing or advance the drilling by stabilising the borehole by use of drilling fluid of appropriate properties. Where practicable, the bottom of the casing should be kept sufficiently far below the borehole to prevent the inflow of soil and the formation of cavities in the surrounding ground, which can release water into the pile concrete when the casing is withdrawn. Where the casing cannot practically be advanced below the bottom of the borehole, for example in compacted sand and gravel, it will be necessary to use other expedients. The S.O. shall be informed of any unforeseen ground conditions encountered during boring. Where hard stratum is encountered during boring, the Contractor shall advance the borehole by means of chiselling or use of pneumatic tools or rock coring buckets with tungsten carbide tip teeth or other equivalent approved means with the approval of the S.O. For purposes of payment of advancing borehole through hard stratum, hard stratum shall be defined as material with Standard Penetration test value of 200 and above. Soil, rock or ground water samples shall be taken and appropriate soil identification tests carried out while boring at every 1.5m intervals or change of strata as per the directions of the S.O. The taking of samples and all subsequent handling, transportation and testing shall be carried out in accordance with BS 5930. The rate of boring shall include for sampling and testing of soil samples.
6.7.19 Use of Drilling Fluid for Stabilising Pile Borehole Where drilling fluid is used to stabilize the borehole, level of the fluid in the excavation shall be maintained so that the fluid pressure always exceeds the pressures exerted by the soils and external ground water and an adequate temporary casing shall be used in conjunction with the method to ensure stability of the strata near ground level until concrete has been placed. The fluid level shall be maintained at a level not less than 1m above the level of the external ground water. In the event of rapid loss of bentonite suspension from the pile excavation, the excavation shall be backfilled without delay. Before resuming excavation at that location the approval of the S.O. shall be obtained.
6.7.20 Spillage and Disposal All reasonable steps shall be taken to prevent spillage of bentonite suspension on the site in areas outside the immediate vicinity of boring. Discarded bentonite shall be removed from the site without undue delay. Any disposal of bentonite shall comply with regulations of the local controlling authority.
6.7.21 Boring Near Recently Cast Piles Piles shall not be bored so close to other piles which have recently been cast and which contain workable or unset concrete, such that a flow of concrete could be induced from or damage caused to any of the piles.
6.7.22 Pumping from Pile Bores
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Pumping from a borehole shall not be permitted unless a casing has been placed into a stable stratum which prevents the flow of water from other strata in significant quantities into the boring, or, unless it can be shown that pumping will not have a detrimental effect on the surrounding soil or property.
6.7.23 Standard Penetration Test When the Contractor has bored to the designed depth or any lower depth as instructed by the S.O., Standard Penetration Tests shall be carried out at the bottom of pile excavation to assist in confirming the founding level. The number and depth at which these tests are carried out shall be at the discretion of the S.O. The cost of carrying out such tests shall be deemed to be included in the Contract Rates.
6.7.24 Proof Coring Where bedrock is encountered during boring, the Contractor shall if instructed by the S.O. bore a further 600mm to establish a proper socketing for the pile. He shall affirm the soundness of the bedrock by coring through the bedrock by a diamond core drill and to determine the rock quality designation and total core recovery in accordance with BS 5930 to a depth of 5 times the diameter of the pile or to the designed pile depth whichever is less. All drill-holes shall be cement grouted on completion. The Contractor shall maintain a diamond core drill at site for this purpose.
6.7.25 Depth of Bored Pile Upon completion of the Standard Penetration Test (SPT) or the drill-hole, the Contractor shall immediately furnish the results to the S.O. After assessing the results the S.O. may instruct the Contractor to proceed with the installation of the bored pile or may instruct the Contractor to further advance the depth of the boring until further SPT or drilling confirms that sound founding level is reached.]
6.7.26 Cleaning of Pile Bore On completion of boring, loose, disturbed material or remoulded soil shall be removed from the base of the pile and the hole shall be cleaned to the satisfaction of the S.O. On final approval of the boring by the S.O., the final depth of borehole shall be measured.
6.7.27 Inspection of Pile Bore Each pile borehole shall be inspected and measured prior to the placing of concrete in it. The excavation must be examined by the inspector or any other representative of the S.O. and permission shall be obtained by the Contractor before proceeding with concreting. The Contractor shall provide at his own cost all the apparatus necessary for inspection, including any electrical apparatus, if required. For dry boreholes, each hole shall be inspected prior to the placing of concrete in it. The inspection shall be carried out from the ground surface in the case where the borehole diameter is less than 750mm. Torches or other approved means of lighting, measuring tapes and a means of measuring verticality shall be provided. Where the borehole diameter exceeds 750mm, adequate equipment conforming to BS 8008 shall be provided by the Contractor to enable the Contractor and the S.O. to descend into the borehole for the purpose of inspection. For wet boreholes, i.e. holes filled with drilling fluid or water, a suitable probe shall be provided to ascertain the evenness and cleanliness of the pile base. In the event that the soil characteristics at the bottom of the borehole is significantly impaired due to ingress of water or is filled with loose disturbed or remoulded soil or foreign material as a result of the Contractor’s prolonged delay in placing of
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concrete, he shall clean the hole again or advance the hole further to a stratum of at least the same soil characteristic as before. The additional cost for boring, carrying out the Standard Penetration Test, and the additional concrete shall be borne by the Contractor.
6.7.28 Disposal of Spoil The Contractor shall be responsible for the disposal of the spoil removed from the pile hole as per the directions of the S.O.
6.7.29 Placing of Reinforcement The steel reinforcement cage consisting of longitudinal bars and spiral reinforcement or lateral ties shall be securely assembled prior to placing in the borehole. Necessary cover blocks shall be provided for the reinforcement cage to ensure a clear cover of at least 75mm to the reinforcement. The reinforcement cage shall be made so that there is no relative displacement of the reinforcement during the construction of the pile and shall be sufficiently strong enough to withstand the impact of falling/discharging concrete.
6.7.30 Continuity of Construction A pile constructed in a stable cohesive soil without the use of temporary casing or other form of support shall be bored and concreted without prolonged delay and in any case soon enough to ensure that the soil characteristics are not significantly impaired.
6.7.31 Concreting - General The method of placing and workability of the concrete shall be such that a continuous monolithic concrete shaft of full cross section is formed. The concrete shall be placed without such interruption as would allow the previously placed batch to have hardened. The method of placing shall be approved by the S.O. The Contractor shall take all precautions in the design of the mix and placing of the concrete to avoid arching of the concrete in the casing. No spoil, liquid or other foreign matter shall be allowed to contaminate the concrete.
6.7.32 Workability of Concrete The workability of the concrete shall be determined by the slump test as describe in Section 3. The concrete shall have slumps of 100mm to 150mm in dry shaft without temporary casing and 150mm to 200mm for concrete placed in dry shaft with temporary casing and 175mm to 225mm slump for concrete placed by tremie under water or drilling fluid. The slump shall be measured at the time of discharge into the borehole. The concrete is to be rejected if the required slump is not met.
6.7.33 Minimum Cement Content The cement content in any mix shall be not less than 350kg/m3. Where concrete is to be placed under water or drilling mud by tremie, the cement content shall be not less than 380kg/m3, or where the pile will be exposed to sea water 400kg/m3.
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6.7.34 Cube Tests Tests cubes shall be taken from each batch of the concrete used in the concreting or as required by the S.O., to determine and control the strength of the concrete in the piles. Test cubes shall be taken in accordance with Section 3.0. The Contractor shall submit certified copies of the result of all tests to the S.O.
6.7.35 Compaction Internal vibrators shall not be used to compact concrete unless the method of use has been approved. Rodding shall be done in the top one metre of the shaft.
6.7.36 Concreting in Dry Boring Approved measures shall be taken to avoid segregation and bleeding and to ensure that the concrete at the bottom of the pile is not deficient in grout. The concrete shall be placed by the use of a hopper with a length of pipe to ensure that the concrete falls centrally to the full depth without striking the reinforcement steel or the sides of the pile excavation.
6.7.37 Concreting Under Water or Drilling Fluid Concrete to be placed under water or drilling fluid shall be placed by tremie unless otherwise approved and shall not be discharged freely into the water or drilling fluid. Before placing concrete, measures shall be taken in accordance with Clause 6.7.27 to ensure that there is no accumulation of silt or other material at the base of the borehole and the Contractor shall ensure that heavily contaminated bentonite suspension, which could impair the free flow of concrete from the pipe of the tremie, has not accumulated in the bottom of the hole. A sample of the bentonite suspension shall be taken from the base of the boring using an approved sampling device. If the specific gravity of the suspension exceeds 1.25 the placing of concrete shall not proceed. In this event the Contractor shall modify or replace the bentonite as approved to meet the Specification. During and after concreting, care shall be taken to avoid damage to the concrete from pumping and dewatering operations. The hopper and pipe of the tremie shall be clean and watertight throughout. The tremie pipe shall extend to the base of the borehole and a sliding plug or barrier shall be placed in the pipe to prevent direct contact between the first charge of concrete in the tremie and the water or the drilling fluid. The pipe shall at all times penetrate the concrete which has previously been placed and shall not be withdrawn from the concrete until completion of concreting. At all times a sufficient quantity of concrete shall be maintained within the pipe to ensure that the pressure from it exceeds that from the water or drilling fluid. The internal diameter of the pipe of the tremie shall be not less than 150mm for concrete made with 20mm aggregate and not less than 200mm for concrete made with 40mm aggregate. The internal face of the pipe of the tremie shall be free from projections.
6.7.38 Extraction of Casing - General
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The extraction of temporary casings to pile shafts shall be carried out in such a manner that no damage shall be sustained by pile being cast or by adjacent piles or structures. A sufficient head of concrete shall be maintained above the bottom of the linings at all times to prevent entry of ground water or the reduction of cross-section of the pile shaft. The casing extractor shall be placed in position before any concrete is placed within the casing so that the extraction may commence as soon as concrete is placed. Casing shall be extracted within two (2) hours of placing concrete. Extraction of casing shall be done by vertical lift, continually plumb, and shall proceed in such a manner as to allow continuous observation of the interior slumping of the concrete.
6.7.39 Workability of Concrete During Casing Extraction Temporary casing shall be extracted while the concrete within them remains sufficiently workable to ensure that the concrete is not lifted.
6.7.40 Vibrating Extractor The use of vibrating casing extractors will be permitted subject to the condition that work shall be carried out in such manner and at such times as to minimise nuisance and disturbance to adjacent structures or newly completed pile.
6.7.41 Concrete Level When the casing is being extracted, a sufficient quantity of concrete shall be maintained within it, to ensure that the pressure from external water, drilling fluid or soil is exceeded and that the pile is neither reduced in Clause nor contaminated. No concrete is to be placed in the boring once the bottom of the casing has been lifted above the top of the concrete, it shall be placed continuously as the casing is extracted until the desired head of concrete is obtained. Adequate precautions shall be taken in all cases where excess heads of water or drilling fluid could be caused as the casings is withdrawn because of the displacement of water or fluid by the concrete as it flows into its final position against the wall of the pile shaft. Where double casings are used in the boring, the proposed method of working shall be with the approval of the S.O. The following checks are to be followed when the extraction of casings commences:i)
Reduced level of the top of the casing and the top of the concrete shall be measured before extraction commences.
ii)
Reduced level of top of concrete shall be measured after casing is extracted.
The reduced level of top of concrete shall be checked at intervals during extraction by suitable means to be agreed on site.
6.7.42 Water Level In the event of ground water level being higher than the required pile head casting level shown on the Drawings, the Contractor shall submit his proposals for approval prior to placing concrete. The pile head shall not be left below the ground water level unless approved precautions are taken.
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6.7.43 Preparation of Pile Heads The top of the pile shall be brought above the cut-off level of the pile to permit all laitance and weak concrete to be removed and to ensure that it can be properly keyed into the pile-cap. Pile heads shall be constructed to the details shown on the Drawings.
6.7.44 Temporary Backfilling After Casting After each pile has been cast, any empty pile hole remaining shall be protected and shall be carefully backfilled as soon as possible with approved materials.
6.7.45 Tolerances The bored pile must be installed so that the axis of the shaft at the top of the shaft is not more than 75mm from its plan location. Piles that are to be installed vertically must be within 2% of plumb for the total length of the shaft.
6.7.46 Existing Services Before the work commences the Contractor shall investigate the site for the presence of electrical cables, water mains and other services that may be damaged in the course of installing bored piles.
6.7.47 Tidy Site The Contractor shall keep the site clear of all unnecessary obstructions such as spoil heaps, discarded wire ropes and reinforcement rods, etc.
6.7.48 Public Safety The Contractor shall ensure that all open boreholes be adequately covered during non-working hours.
6.7.49 Daily Records The Contractor shall supply to the S.O. in duplicate a complete records of all piles installed in the day signed not later than noon of the next working day after the pile has been installed. The record shall include the following:(a)
Identification Number of pile
(b)
Location
(c)
Ground Level
(d)
Diameter of shaft
(e)
Top and bottom elevation of shaft and cut-off level
(f)
Depth of boring
(g)
Depth of rock coring, RQD etc.
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(h)
Details of all strata bored
(i)
Depth of water table
(j)
Details of in situ tests like SPT carried out at various levels and at bottom of boring
(k)
Details of temporary casing
(l)
Details of drilling fluid used
(m)
Volume of concrete used in forming the pile shaft
(n)
Length, diameter and other details of reinforcement cage
(o)
Elevation of top of rebar cage before and after concrete is poured
(p)
Date and time of starting, stopping, delays, if any and finishing of pile shaft
(q)
Any unusual occurrences that could affect the integrity of the bored pile construction
The signed record shall be part of the record for the Works.
6.7.50 Integrity Testing of Piles - General Piles shall be tested for detection of major faults, necking, discontinuation, pile length and cross sectional area of the pile. The integrity testing of piles shall be carried out by a specialist agency to be appointed by the Contractor subject to the approval of the S.O. The results of the test shall be fully recorded and interpreted for submission to the S.O. for further analysis. No pile caps shall be constructed on piles selected for integrity testing until the Contractor submits the integrity test report. The Contractor shall make due allowance in his programme of work for such integrity tests. The delay in carrying out integrity test, submission of report and any necessary rectification of the pile shall not entitle the Contractor to any extension of time. The Contractor shall provide the testing team with a site plan showing the pile layout and a list of the piles to be tested with the date of concreting, total length, length of casing (if any), diameter and volume of concrete used, plus any other relevant factors.
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6.7.50.1 Shock Test
a) Preparation of Pile Head for Shock Test The pile head shall be clearly exposed, free from debris, etc. and not more than 1.0m above or below ground level, otherwise the surrounding soil shall be built up or excavated to meet this condition. The pile head shall be smooth over its complete perpendicular to the vertical axis of the pile.
cross-section, free from irregularities and shall be
The pile head shall consist of sound concrete. This shall be achieved during the concreting of the pile by flushing out all weak mortar, etc. from the top of the pile head and carefully screening off to provide a smooth level surface in sound concrete. Alternatively if the pile head is prepared after concreting, all weak mortar, broken concrete, etc. shall be removed from the pile head, to expose sound concrete and the head left horizontal over its complete cross-section. After cleaning it off to ensure a sound bond, a very thin screed (maximum 1cm) of strong sand/cement mortar rapid hardening or a compound such as FEBFLOR shall be spread to provide a smooth working surface for the shock test equipment. The mortar shall be allowed to harden before testing. The soundness shall be tested by means of light blows from a small hammer. The pile head shall be free from any structure, building concrete or concrete spillage prior to testing. Any reinforcement or other inclusions protruding from the pile head shall not prevent the testing team from giving the pile the required impact force over the center of the pile and the placing of a 5cm diameter (approximately) electronic pick-up at about 10cm from the periphery of the pile. Access shall be provided for the service van within 30m of the pile. b) Shock Test Equipment The shock which is to be imparted on to the pile head shall be carried out using a suitable size hand held hammer or any approved method which is capable of transmitting vibration to the base of the pile shaft. The electronic-pick-ups located on the pile head shall be approved velocity transducers or accelerometers connected through an approved frequency analyser to an X-Y plotter. The mechanical admittance shall be plotted on a vertical scale and the frequency on the horizontal scale. Both the horizontal and vertical scales shall be varied as required. The equipment shall have an independent power supply. c) Shock Testing Before testing, the heads of the piles shall be inspected by the testing team for regularity and soundness and any unsatisfactory pile heads shall be reported to the S.O. They shall be made good by the Contractor as instructed by the S.O. and smoothed off using a suitable epoxy mortar if necessary. Preliminary tests shall be carried out to establish the appropriate scales and to check the electronic circuit. 6.7.50.2 Sonic Logging Method
Selected number of piles shall be tested by Sonic Logging Method to check their integrity. The number and choice of piles to be tested shall be decided by the S.O.
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Sonic Logging Method is a method of investigation using the lateral transmission of waves consisting of emission of an ultra sonic vibration in an access tube filled with water and capturing this vibration at the same level in another tube within the pile shaft. This operation is repeated at a high frequency and at level sufficiently close to each other in order to get a continuous recording over the entire length of the pile shaft. The tubes for integrity tests by sonic logging shall be of internal diameter not less than 50mm with no internal projections or couplings. They can be of mild steel pipe or G.I. Pipe. Four (4) nos. of tubes are required for each selected pile of diameter less than 1.3m while six (6) nos. are required for each selected pile of diameter greater than 1.3m. The tubes shall be cleaned with non-greasy product before use in order to prevent oil films from causing problems of adherence between the tube and the concrete. This could cause a variation that might be incorrectly interpreted as a significant defect in the pile. The tubes shall be fixed to the vertical bars with equal spacing on the inside perimeter of the links. The tubes shall be watertight with the bottom of the tube sealed and suitably weighed to prevent floating. The upper ends of the tubes must be closed and extended to at least 0.5m above the concrete surface to prevent debris or concrete from falling into the tube. The tubes shall be secured to the internal face of the reinforcement cage at equal distance from each other on the circumference. In all cases, the tubes shall rest on the founding level of the pile so that the full length of the pile can be tested. The type of tube and condition of sealing shall be checked and approved by the S.O. before installation. The tube shall be filled with water to provide the necessary acoustic coupling, and then plugged or capped before concreting. After conducting the tests, all metal tubes shall be grouted and water in the tubes displaced. The grout shall be dense cement grout with an approved expanding agent. Payment for the grouting work shall be deemed to have been included in the rate of testing. 6.7.50.3 Records
The time required to carry out the integrity test shall be recorded along with records of starting time and finishing time. The results of the tests shall be presented in reported form by the testing firm and must be signed by a professional engineer. The report shall include comprehensive engineering analysis of the test results for each pile taking into consideration the soil condition and any other relevant factor. Interim reports of each pile or group of piles testing in one day shall be submitted to the S.O. within 5 days of the completion of the test or tests. A final comprehensive report shall be submitted to the S.O. within 10 days of the completion of the last test or tests.
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6.8
Micro Piles
6.8.1 General The micropiling shall be undertaken by a specialist sub-contractor employed by the contractor, subject to the approval of the S.O. The specialist sub-Contractor shall satisfy the S.O. that he has the necessary experience in works of a similar nature and magnitude.
6.8.2 Submission by the Contractor The following submissions are required from the Contractor: a) Proposals Not later than 2 weeks before the date proposed for the commencement of the micropiling the Contractor shall submit details of his proposals to the S.O. for approval. Such details shall include: -
equipment to be used including standby capacity and spares personnel construction sequence grouting pressure and techniques proposed grout mix any other information requested by the S.O.
b) Drillings and grouting records Whenever drilling and grouting operations are in progress the Contractor shall submit daily records to the S.O. which shall detail all aspects of the work carried out in a format to be agreed by the S.O. The records shall be submitted in duplicate on the morning following the day to which the report refers.
6.8.3 Equipment The Contractor shall have at his disposal all the necessary equipment for drilling and concreting holes at least to the depth specified. The equipment provided shall be adequate to carry out the work within the time scale allowed in the programme.
6.8.4 Materials Materials shall comply with the relevant requirements in the Specification. Joints in the reinforcement shall be such that the full tensile and compressive strength of the base is effective across the joint and made in such a way that there is no relative displacement during subsequent operations.
6.8.5 Method of Construction The Contractor shall advance the hole using a simultaneous drilling and casing system or method approved by the S.O., that ensures full support to the hole over its full depth until casing withdrawal. Grouting of the micropiles shall be carried out in a continuous operation with a tremie tube to ensure the grout is injected from the bottom of the hole upwards. The quantity of grout shall be recorded.
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Grout shall be mixed on Site and shall be free from segregation, slumping and bleeding. Grout shall be pumped into its final position in one continuous operation as soon as possible and in no case more than half an hour after mixing.
6.8.6 Grout Mix The grout to be used shall be made with non-shrink cement grout and may include chemical admixtures as approved by the S.O. The water/cement ratio shall not exceed 0.45. Unless otherwise directed by the S.O. one set of 150mm cubes (six cubes per set) shall be taken daily during grouting operations from a randomly selected batch; curing and testing shall be in accordance with BS EN 12390 - 1. Three cubes from each set shall be crushed at 7 days and the remaining three at 28 days. The minimum 28 days cube crushing strength shall be 30N/mm. The Contractor shall propose a suitable mix for approval by the S.O. and test mixes shall be made up from the variations thereof, to determine the optimum mix to be used in practice. These trial mixes shall be made and tested well in advance of the time planned for the construction of micropiles.
6.8.7 Rejected Micropiles If any micropile fails to comply with the specified requirements in any respect which renders it not measurable for payment, its construction shall still be completed to the satisfaction of the S.O. unless otherwise permitted by the S.O.
6.9
Pile Testing
6.9.1 General Unless otherwise specified, pile tests shall be carried out as described in this Clause of the Specification.
6.9.2 Test Load and Kentledge The test load shall be applied by means of hydraulic jack of adequate capacity fitted with measuring devices capable of registering loads in increments not exceeding 5 tons. The hydraulic jack and measuring devices shall be approved by the S.O. before use. All measuring devices used shall be provided with calibration certificates. Time lapsed for the calibration date shall not exceed 12 months. The kentledge shall be provided by a heavy mass of dead load, exceeding the maximum test load required, supported centrally over the test pile on suitably constructed temporary staging or by means of anchor piles. If anchor piles are used to provide reaction for the jack, these piles shall not be closer to the test pile centre to centre than 1.5m or 5 pile diameters or equivalent whichever is the larger. Anchor piles, which later form part of the piled foundation to the structure, shall be appropriately re-driven to the required set or level as directed by the S.O. all to his full satisfaction.
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6.9.3 Settlement Measurement Vertical movements of the test pile shall be measured by at least two dial gauges, with a minimum of 25mm travel, graduated in 0.025mm divisions. The gauges shall be erected on stiff steel beams, the ends of which shall rest on or be fixed to reliable supports. Such supports shall be located not closer than 1.8m from the test pile, and shall be rigidly fixed to the ground to a depth of not less than one metre of concrete surround. In addition, the elevation of the supports shall be checked frequently with reference to a fixed benchmark. The entire measuring assembly shall be properly protected against rain, direct sunlight and other disturbances that might affect its reliability. Temperature readings shall be taken when requested by the S.O.
6.9.4 Equipment and Personnel for Load Test All kentledge staging, anchor piles, equipment, shelter, supports, and the like required for the load test shall be provided by the Contractor, who shall also provide all necessary facilities to enable the S.O. to check all readings during the progress of the test. The S.O. will supervise and direct the whole process of the test and provide skilled staff to assist in taking and recording all readings. The Contractor shall provide all other labour required for the proper execution of the test, including the construction and dismantling of the load staging and handling of the kentledge materials on and off the load stage, and the like and for the continuous and competent watching of the whole assembly, all to the full satisfaction of the S.O.
6.9.5 Procedure of Testing The `MAINTAINED LOAD' method of testing shall be carried out on the test pile. The S.O. may at his discretion decide to carry out the `CONSTANT RATE OF PENETRATION' method of testing on completion of the Maintained Load Test. (a) Maintained load test The load shall be applied in increments of 25% of the working load until a maximum test load of twice the working load is reached. Each increment of load shall be applied as smoothly and as expeditiously as possible. Settlement readings and time observations shall be taken before and after each new load increment. A settlement-time graph shall be plotted to indicate when the rate of settlement of 0.05mm in 15 minutes is reached. A further increment of load shall be applied when this rate of settlement is achieved or until a minimum time of 2 hours elapsed, whichever is later. The process is repeated until the maximum test load is reached. The maximum test load shall then be maintained for a minimum of 24 hours, and time-settlement readings shall be taken in regular intervals as for the other load stages.
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The test load shall then be decreased in four equal stages and time-settlement readings taken as described aforesaid until the movement ceases. At least 60-minute intervals shall be allowed between the unloading decrements. (b) Constant rate of penetration test The load shall be applied at a constant rate of penetration of a value varying between 0.75mm per minute to 1.5mm per minute, the rate to be so chosen as to suit the available pumping equipment. Both settlement and time readings shall be recorded every minute. Further loading shall be discounted when the loading varies directly as the penetration in the case of end-bearing piles in sand or gravel or when the rate of penetration is constant without further increase in the load in the case of friction piles in clay. Loading shall then be released gradually and rebound readings taken.
6.9.6 Records of Test The Contractor shall submit two copies of all records of results, not including the original copy, together with load-settlement and load-time graphs to the S.O. on completion of each test.
6.9.7 Interpretation of Test Results The S.O.’s interpretation and conclusions arrived at on the test results shall be final. When the pile test as prescribed has been carried out, the pile so tested shall be deemed to have failed if:a)
the residual settlement after removal of the test load exceeds 6mm, or
b)
the total settlement under Design Load exceeds 13mm, or
c)
the total settlement under twice the Design Load exceeds 38mm.
6.10 Rejection of Piles Piles deviating from position or inclination more than the allowable tolerances shall be liable to rejection at the discretion of the S.O. If any pile is rejected, either due to its incorrect position, poor workmanship, poor materials or due to any other causes, the S.O. shall order an additional or more piles, if necessary, to be installed and incorporated in the redesigned pile cap. If at the discretion of the S.O., the Contractor installs an additional pile or piles, the Contractor will not be paid for the rejected pile but he will be paid for one pile of the average length of the additional piles. The cost of the second pile, if two are ordered, plus the additional cost of the pile cap over the original design and all other costs involved in the amendments necessary to the supported structure as a result of the altered positions of the piles and the special design of the pile cap shall be borne by the Contractor.
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6.11 Dynamic Pile Load Test Method 6.11.1 General Dynamic load test for pile shall include: (i)
Monitoring of pile response when the pile is subjected to an impact provided by the pile driving hammer. Monitoring shall continuous with time and shall be carried out for each hammer blow until satisfactorily completion of pile installation;
(ii)
Signal matching using TNOWAVE or CAPWAP techniques to match the measured response with an approved pile-soil model to determine the static pile resistance, the distribution of shaft resistance, and the base resistance. Signal matching shall be carried out for each hammer impact to enable determination of the pile resistance with depth.
Dynamic load test for a specified number of working piles shall include monitoring of pile response when the pile is subjected to an impact provided by the pile driving hammer after the completion of driving.
6.11.2 Measurements Measurements of strain, force and acceleration shall be carried out close to the pile head. Such parameters shall be measured continuously with time and stored on electronic data capture units with the capability of producing graphs of measured:(i)
Force – time;
(ii)
Acceleration – time;
(iii)
Velocity – time;
(iv)
Displacement – time;
during and after pile installation. The permanent penetration per blow and the temporary compression of the pile and soil system shall be measured independently of the instrument being used to record the dynamic test data.
6.11.3 Field Data Processing Immediate field data processing shall be carried out to identify malfunctions. The following computations shall be carried out during pile installation:(i)
The force measurement shall be continuously balanced except during the impact event;
(ii)
The acceleration must be integrated or displacement must be differentiated over time to obtain velocity. The resulting velocity shall be continuously zero except during impact;
(iii)
The force and velocity shall be output on a display unit during measurements;
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(iv)
The product of force and velocity shall be integrated over time to obtain the energy transferred to the top of the pile. The energy shall be continuously zeroed except during impact;
(v)
The maximum values of force, acceleration, displacement, velocity, energy, force at maximum velocity and minimum force shall be determined.
6.11.4 Measurement Devices All instruments for measurements and all equipment for receiving and processing data shall be suitable for the purpose and to the S.O.’s approval. Equipment required to be attached to the pile shall be appropriately positioned and fixed to the approval of the S.O. No optical measuring device shall either for strain or velocity measurement shall be permitted. Equipment shall be fixed as follows:(i)
Acceleration shall be measured by suitable transducers attached to the pile at a distance not less than 1 pile diameter below the top of the pile. At least two accelerometers shall be used at the pile surface and so arranged to cancel the effects of bending;
(ii)
Accelerometers used shall be linear to at least 1000 x g and 10kHz;
(iii)
In the event force measurements are made using strain transducers, such transducers shall be securely attached on the pile such that no slippage shall occur. Bolt-on or glue-on transducers may be acceptable for use. The strain transducers shall be linear over the entire range of pile strains. The natural frequency when attached to the pile shall be in access of 10kHz.
(iv)
Force transducers shall have an impedance of between 50% to 100% of the impedance of the pile near the top. The output signal shall be linear up to the maximum axial pile force at the top of the pile. The connection between the force transducers and the pile top shall have the smallest possible additional mass.
6.11.5 Hammer The hammer and all site equipment shall be capable to delivering an impact force sufficient to mobilize the equivalent specified test load without injury to the pile.
6.11.6 Preparation of Pile Head The preparation of the pile head for the application of the dynamic load test shall include, where appropriate, trimming the head, cleaning and building up the pile using materials which will at the time of testing safely withstand the impact stress. The impact surface shall be flat and right angle to the pile axis. The pile head shall be exposed for a minimum length of 3 times the pile diameter below the pile top. The sides of the pile head must be easily accessible for the installation of gauges or transducers.
6.11.7 Personnel All personnel involved in Dynamic Load Testing shall be person experienced in the task.
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6.11.8 Preliminary Results The following preliminary results shall be provided to the S.O. within 24 hours of the completion of the pile test. These shall include the following:(i)
The assumed damping factor;
(ii)
The assumed wave speed;
(iii)
The maximum force applied to the pile head;
(iv)
The maximum head velocity;
(v)
The maximum energy impact to the pile;
(vi)
The maximum tension experience by the pile;
(vii)
The field estimated static resistance;
(viii)
The maximum driving resistance.
6.11.9 Detailed Report Subsequently a full detailed report shall be given to the S.O. in triplicate within 10 days of the completion of testing for all piles. These shall include the following:(i)
Report all information given in preliminary report;
(ii)
Information of pile size and working load;
(iii)
Date of pile installation
(iv)
Date of test;
(v)
Pile identification number and location;
(vi) (vii)
Length of pile below commencing surface; Total pile length including projection above commencing surface at time of test;
(viii)
Length of pile from instrumentation position to pile toe;
(ix)
Hammer type and other relevant details;
(x)
Blow selected for report;
(xi)
Estimate of static pile capacity including distribution of shaft resistance and base resistance;
(xii)
Pile integrity;
(xiii)
Force/velocity versus time trace;
(xiv)
Upward travelling wave versus time trace;
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(xv)
Displacement versus time trace.
6.11.10 Defective Piles Defective piles, which are not ordered by the S.O. to be replaced by additional piles, shall however be remedied by a method proposed by the Contractor and approved by the S.O.
6.12 Piling Records The Contractor shall keep a record of all piles driven at the Site. A copy of the field record of the piling work done each day shall be given to the S.O. within 24 hours. The Contractor shall record the number of blows for each 300mm of penetration of the advance piles and submit the following information to the S.O.: (a)
Serial number of pile on plan
(b)
Pile size
(c)
Date driven
(d)
Details of hammer and strokes
(e)
Penetration of pile
(f)
Sequence of driving in groups
(g)
Details for the final 300mm penetration including final set
(h)
Details of any interruption in driving
(i)
Details of re-driving
(j)
Position and level of pile joints
(k)
Elastic compression of pile Cp, and quake of sub-soil Cq for the last 10 blows On completion of all piling work, the Contractor shall prepare and submit to the S.O. two sets of complete records including drawings showing details of all piles driven at the Site relative to the Survey Department level.
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7.0
STRUCTURAL STEELWORK .....................................................................7-1 7.1
General .............................................................................................7-1
7.2
Materials ...........................................................................................7-1
7.3
Surveys and Setting Out .................................................................7-2
7.4
Drawings...........................................................................................7-2
7.5
Workmanship ...................................................................................7-2
7.6
Connections .....................................................................................7-3
7.7
Bolting ..............................................................................................7-3
7.8
Welding.............................................................................................7-4
7.9
Holing................................................................................................7-6
7.10
Slab Bases and Caps.......................................................................7-6
7.11
Gusseted Bases and Caps..............................................................7-6
7.12
Compression Joints and Stanchion Splices .................................7-6
7.13
Stiffeners ..........................................................................................7-7
7.14
Clearances........................................................................................7-7
7.15
Marking .............................................................................................7-7
7.16
Protective Painting and Coatings...................................................7-7
7.17
Erection ............................................................................................7-9
7.18
Erection Tolerances.......................................................................7-10
7.19
Grouting..........................................................................................7-10
7.20
Inspection.......................................................................................7-11
7.21
Subletting .......................................................................................7-11
7.22
Required Information from the Contractor ..................................7-11
7.23
Fire Protection ...............................................................................7-12
APPENDIX 7.1:
Table 18 and 19 of British Standard 5135
LIST OF TABLE Table: 7.1 – Weld Test Requirements Table: 7.2 – Painting And Coating Table: 7.3 - Summary Of Information Required From The Contractor For Approval
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Section 7 - Structural Steelwork
7.0 STRUCTURAL STEELWORK 7.1
General
The works shall be constructed strictly in accordance with the drawings. Any ambiguities in or discrepancies between the Contract Documents shall be reported to the S.O. immediately.
7.2
Materials
Unless otherwise specified all structural steel shall comply with the requirements of the current issues of the following British Standards where appropriate:BS 4
Parts 1 and 2: Structural Steel Sections
BS 10002-1
Tensile Testing of Metallic Materials. Method of Test at Ambient Temperature
BS 5950
Structural Use of Steelwork In Building
BS EN ISO 1461
Hot Dip Galvanized Coatings on Fabricated Iron and Steel Articles
BS 1449-1.1
Steel plate, sheet and strip: Carbon and Carbon-manganese Plate, Sheet and Strip
BS EN 10051
Specifications For Continuous Hot-Rolled Uncoated Plate, Sheet And Strip of Non Alloy And Alloy Steel
BS EN 10143
Continuously hot dip zinc coated and iron zinc alloy coated steel
BS 3692
Isometric Precision Hexagonal Bolts Screws and Nuts
BS 4190
Isometric Black Hexagon Bolts, Screws and Nuts
BS 4320
Metal Washers for General Engineering Purposes
BS 7668
Weldable Structural Steel Hot Finished, Structural Hollow Section in Weather Resistant Steels
BS 4395
High Strength Friction Grip (HSFG) Bolts for Structural Engineering
BS 4604
The Use of High Strength Friction Grip (HSFG) Bolts in Structural Steelwork
BS EN 10210-2
Hot Finished Structural Hollow Sections of Non-Alloy and Fine Grain Structural Steel
BS EN 10056-1
Specification for Structural Steel Equal and Unequal Angles
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Section 7 - Structural Steelwork
The grade of steel to BS 7668 shall be as specified on the drawings. Steel shall be marked in accordance with BS 7668. Where steels of different grades are used they shall with the exception of Grade 43A have additional markings as specified by the S.O. Unless specified or approval otherwise stainless steel shall be austenitic stainless steel grade 304 or 316 complying with BS EN 10051. Cold formed sections shall be manufactured from steel complying with BS 1449 or BS EN 10143. All steel shall be free from loose mill scale rust and shall be straight unless required to be curvilinear form, and shall be free from twists. The Contractor shall supply the S.O. with the Manufacturer's Mill Certificate in accordance with BS 7668. When required by the S.O., the Steelwork Contractor shall submit test certificates relating to the steels used in the work. The tests shall be those described in the appropriate British Standards.
7.3
Surveys and Setting Out
The Steelwork Contractor shall be responsible for the survey of the site so far as it applies to the steelwork.
7.4
Drawings
The steelwork Contractor shall prepare all necessary calculations (including those relating to connections, plates, etc), detail arrangements and workshop drawings. Two copies of these to be submitted to the S.O. for approval prior to fabrication. The phasing of drawing submissions and the time allowed for inspection of drawings shall be agreed with the S.O. Workshop drawings shall be prepared taking full account of the support and dimensional requirements of cladding and other specialist sub-contractors. The S.O.'s approval shall relate only to the adequacy of the connections and shall not relieve the Steelwork Contractor from any responsibility of rectifying, at his own expense, errors in the steelwork due to drawing office errors subsequently discovered.
7.5
Workmanship
Fabrication shall not commence without the S.O.'s consent. The workmanship throughout is to comply in all respects with the recommendations of BS 5950 and be to the satisfaction of the S.O. Fabrication tolerances shall comply with the requirements of BS 5950 Part 2. Unless noted otherwise the ends of all tubular sections are to be sealed against the ingress of moisture.
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Section 7 - Structural Steelwork
Permissible variation in the specified camber of beams or trusses regardless of cross section shall not exceed - 0mm or + 6mm.
7.6
Connections
The steelwork contractor shall design all the connections, including holding down assemblies, to BS 5950, except those specifically detailed, to resist the forces and moments as given on the drawings. Unless otherwise specified by the S.O., all shop connections are to be formed by arc welding and all site connections with High Strength Friction Grip (HSFG) bolts or black bolts. All site bolts are to be sheradised. Should the Steelwork Contractor elect to use any alternative form of connection these shall be submitted to the S.O. for his approval. The Contractor shall allow in his rates for all welding, bolts, cleats, end plates, gussets and stiffeners, unless these are specifically measured in the Contract Documents. Unless noted otherwise or specifically approved by the S.O., connections shall be formed with a minimum of 2M20 8.8 grade bolts, 6mm fillet weld and 8mm thick plate. Site welding and alterations to steelwork on site shall not be permitted without the detailed approval of the S.O.
7.7
Bolting
The dimensions of black bolts shall conform to the requirements of BS 3692 and BS 4190. In connections which rely on the shear strength of the bolts, the correct length of bolt is to be used to avoid any thread portion of the bolt being within the thickness of the parts bolted together. Washers are to be provided under all nuts except when it is necessary to rotate the head of the bolt. In this instance the washer is to be provided beneath the head. Where necessary, washers shall be tapered or otherwise suitably shaped to give the nuts and heads of bolts a satisfactory bearing. Where High Strength Friction Grip bolts are specified or their use approved by the S.O. they shall be in accordance with the requirements of the current British Standard BS 4395. Unless otherwise specified, all High Strength Friction Grip bolts are to be used in conjunction with load indicating washers and the following procedure for fixing strictly adhered to: (a)
Ensure that the surfaces in contact are clean and free from grease, loose rust, loose scale and paint.
(b)
Ensure that the bolts used are of the High Strength Friction Grip type. (3 radial lines on the bolt head in the case of Grade 8.8 bolts. In the case of Grade 10.9 bolts 3 radial lines and ‘109’ marked in addition on the bolt head.)
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Section 7 - Structural Steelwork
(c)
Wherever possible, the load indicating washer must be placed under the head of the bolt with the protrusions towards the head. A hardened steel flatwasher should be placed under the nut which should then be tightened until the gap between the bolt head and the washer is 0.375mm.
(d)
Where it is not possible to fit a load indicating washer under the bolt head, then it may be placed at the nut end of the bolt with a special 'nut faced washer' fitted between the load indicating washer (protrusions in contact with the NF washer) and the nut. Care must be taken to ensure that the NF washer is fitted the right way round (sharp corner up to the nut) and is concentric with the nut.
(e)
If the nut is to be tightened against an inclined face then a hardened steel tapered washer must be placed under the nut. If the bolt head is on the inclined face and this slope is less than 3 degree (which covers all universal beams) then a tapered washer is not required.
All the foregoing is based on the assumption that the nut will be tightened. Should, for any reason, the bolt head be rotated, then the load indicating washer should be placed under the nut with the protrusions towards the nut and with a NF washer. If the bolt head is to be tightened against an inclined face greater than 3 degree, then a tapered washer will be required under the head. Should there be more than four bolts per group of HSFG bolts, then the bolts are to be tightened in sequence, from the centre of the group to the outside. When the whole group is tightened, the first bolts tightened should be checked to make sure that the gap is still 0.375mm and if necessary further torqued to bring the gap to this dimension. If any bolt is found to have been tightened so that the gap is less than 0.375mm, then no attempt is to be made to slacken off the bolt to reach the desired dimension and it must be left as it is. If, for any reason an HSFG bolt has to be removed or loosened after it has been torqued up, then it is to be discarded together with the load indicating washer, and new bolts and washers used. The facing surfaces of a HSFG connection must be in contact along the whole length of the joint as the load is transmitted via friction through the bearing surfaces. If a joint is poorly aligned then this member shall be corrected or a tapered pack for the full length of the joint used. The pack must be in contact with the full length of the joint. Should the Steelwork Contractor elect to adopt alternative types or methods of fixing HSFG bolts in accordance with BS 4604, then a Specification shall be submitted to the S.O. together with a proposed method of testing, prior to their use on site.
7.8
Welding
Welding shall be in accordance with the following British Standards: BS 1011-1 Specification for Process of Arc Welding of Carbon and Carbon Manganese Steel. The Steelwork Contractor shall provide evidence to the satisfaction of the S.O. that the welding operators are capable of passing the tests specified in BS EN 287 and BS 4872. The Steelwork Contractor shall supply details of his proposed welding procedure for all full strength butt welds and for any other welds specifically required by the S.O.
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Section 7 - Structural Steelwork
The information supplied shall include: • • • • • • • •
Type size and manufacturer of electrode Current and arc voltage Number and arrangement of runs in multiweld runs Position of welding Pre or post heating Preparation of surfaces and welding sequence Use of backing plates or back gouging Plus any further relevant information
Site welding will, in general, only be permitted in cases where factory fabrication is impractical, in which case minor site welding will be allowed. Site welding shall not be carried out in adverse weather unless adequate protection has been provided from the rain and wind. All welds shall be tested by visual examination by the steelwork contractor. Should more rigorous methods of weld testing be required they are described in Table 7.1 and the Contractor is to include in his rates for carrying out all these tests. Table: 7.1 – Weld Test Requirements
Weld Type
Test
Extent
Acceptance Criteria to BS 5135 Tables 18 & 19*
A) Shop Welding Visual
All
100%
Magnetic Particle
Fillet
100% 10% of all welds in each batch
Ultrasonic
Butt
20% of all welds in each batch
Magnetic Particle
Fillet
100%
Ultrasonic
Butt
100%
Category B
B) Site Welding
Note
1 2. 3. 4. * **
Category B
Final examination of a welded joint shall be carried out not less than 16 hours from the time of completion of the weld. Visual inspection to be in accordance with BS 6072. Magnetic particle inspection to be in accordance with BS 6072. Ultrasonic examination to be in accordance with BS EN 1714. Updated Standard shall be BS EN 1011 Refer Appendix 7.1
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Section 7 - Structural Steelwork
Should it be shown that 5% or more of the welds tested are unsatisfactory then the steelwork Contractor shall test all welds at no additional cost to the Contract. All welds failing to comply shall be redone and tested at no cost to the contract. Any welds failing to comply with additional tests on site as instructed by the S.O. shall be redone and retested at no cost to the contract.
7.9
Holing
All work in connection with holing of members is to be carried out in accordance with BS 5950 unless otherwise specified by the S.O. The Steelwork Contractor shall provide such holes in the members as may be required or specified by the S.O. for other trades to fix to or pass their work through. Holes to be used for bolted or riveted connections shall not be formed by a gas cutting process. Finished holes shall be not more than 2mm in diameter larger than the diameter of the black bolts passing through them unless specified by the S.O. Holes for HSFG bolts are to be as specified in BS 4604 Part 1.
7.10 Slab Bases and Caps Slab bases and slab caps, except when cut from material with true surfaces, shall be accurately machined over the bearing surfaces and shall be in effective contact with the end of the shaft. A bearing face which is to be grouted direct to a foundation need not be machined if such a face is true and parallel to the upper face. Baseplates that are to be grouted direct to a foundation are to be drilled with 10mm diameter breather holes at a spacing of one hole per 0.05m² or part thereof. The holes shall be set away from the edge of the baseplate.
7.11 Gusseted Bases and Caps Ends of compression members depending on contact bearing shall be machined true and at right angles to the shaft after having the component parts (i.e. gusset plates, angles etc) fixed permanently to the shaft. Care shall be taken in fixing the component parts to ensure that the minimum thickness of material has to be removed to obtain a true and level surface. In cases when it is impractical to machine the ends of the compression members, then connections capable of carrying the full load are to be provided.
7.12 Compression Joints and Stanchion Splices Ends of compression members meeting at a splice or bearing on a slab division plate, except when machine sawn true and square, shall be accurately machined over the full bearing area of the member.
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Section 7 - Structural Steelwork
Unless otherwise specified flange and web cover plates are to be provided sufficient to hold the connected members accurately in place. The length of the flange cover plates are not to be less than the breadth of the stanchion flange. Unless otherwise shown on the drawings or otherwise noted, stanchion splices are to be approximately 500mm above floor level.
7.13 Stiffeners Load bearing stiffeners shall be provided in the webs of all beams and girders at all points where the concentrated load exceeds the carrying capacity of the web and at other points that may be specified by the S.O. The stiffeners shall be arranged symmetrically about the web where possible. The ends of the stiffeners shall be fitted to provide a tight and even bearing upon the loaded flanges and sufficient weld provided between the web and stiffeners to carry the full load. Stiffeners which are welded to the webs need not be prepared for bearing on the flanges provided that the welds between the stiffeners and flanges are capable of sustaining the full load. Stiffeners shall not be joggled but shall be packed out solid from the web. Should intermediate stiffeners be provided it is not necessary for the ends of these stiffeners to be prepared for bearing but they are to be of sufficient length to extend from flange to flange.
7.14 Clearances The erection clearance for cleaned ends of members connecting steel to steel shall not be greater than 2mm at each end. The erection clearance at ends of beams without web cleats shall be not more than 3mm each end.
7.15 Marking Each piece of steelwork shall be distinctly marked before delivery in accordance with a marking diagram. Where steelwork is to remain exposed in the finished structure, markings should be painted on, so as not to impair the finished appearance. Hard stamping or the use of welded erection marks may only be used with the approval of the S.O.
7.16 Protective Painting and Coatings When omitted from the protection summary Table 7.2 decorative painting of steelwork is to be carried out as specified by the S.O. When protection of the steelwork from corrosion is specified, the type of treatment and preparation of the steelwork to receive same, is to be in accordance with BS 5493 and ISO 12944, and the surface finish of blast-cleaned steel in accordance with BS EN ISO 8501-1 and BS EN ISO 8503. The maximum time lag between cleaning steel and applying primer shall be four hours.
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Section 7 - Structural Steelwork
The minimum specific protection requirements shall be able to withstand C4 environment and a high durability (> 15 years design life) coating system in accordance with ISO 12944. The proposed protection system is listed in the attached protection summary tables. The Contractor shall furnish the S.O. manufacturer's data sheets for the paints he proposes to use. Paint thickness tests are to be carried out at the works and Test Certificates are to be forwarded to the S.O. Wherever possible paint colours or shades shall be chosen so that successive coats are of different hues and readily distinguished. When contact surfaces are to be painted they are to be brought together while the paint is still wet. Surfaces which are to be jointed with HSFG bolts must not be painted but are to be prepared as specified in BS 4604. Site painting shall not be done when humidity is such as to cause condensation on the surface to be painted. Galvanising is to be carried out in accordance with BS EN ISO 1461 'Zinc Coatings on Iron and Steel Articles'. Modifications made to members and fittings to facilitate galvanising are to be approved by the S.O. The top of the flanges of steel beams for use in composite construction are to remain unpainted. No primer that is deleterious to the welding operation will be permitted on this surface. All shop welds and shop bolted connections shall be blast cleaned and painted to the same standard as the adjacent steel. All weld slag and spatter shall be removed. Any areas where paint has been damaged shall be made good to a standard equivalent to that of the adjacent paintwork. If damage has exposed parent metal local re-blasting may be required. The maximum time lag between cleaning steel and applying primer shall be two hours. All materials shall be stored and applied strictly in accordance with the manufacturers’ instructions.
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Section 7 - Structural Steelwork
Table: 7.2 – Painting and Coating ELEMENT
-
All structures
SURFACE PREPARATION
A)
-
Abrasive blast clean to Sa 2.5 (ISO 8501-1) or SSPC-SP 10
Works Protection
Primer
min. 50 microns DFT
Intermediate
min. 125 microns to 150 microns DFT Micaceous Iron Oxide (shall have 60% solids content and indefinite overcoating time). min. 50 microns DFT High Solids Polyurethane
Finish
B)
Epoxy Zinc Rich Primer (minimum 85% epoxy zinc content)
Site Protection
Repair all welding joints and damage by power tool cleaning to St 2 of ISO 8501-1 Touch up Primer Finish
125 microns DFT 50 microns DFT
High Solids epoxy High Solids polyurethane
Note: DFT – Dry Film Thickness
7.17 Erection The delivery programme of the steelwork and the rate of delivery shall conform to an erection sequence which shall be prepared and submitted to the S.O. at the start of the Contract. The sequence shall be prepared in collaboration with the General Contractor. The Steelwork Contractor shall provide all equipment necessary for the erection of the steelwork, and shall be responsible for all claims in respect of any patent devices in connection therewith. During erection, the steelwork shall be securely bolted or otherwise held to ensure that no part of the structure is over-stressed or liable to collapse. Any damage to steel members resulting from neglect of the above shall, on the instructions of the S.O., be repaired or replaced by the Steelwork Contractor at his own expense.
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Section 7 - Structural Steelwork
7.18 Erection Tolerances The following are the maximum deviations permitted in the erection of the steelwork: a)
Plumb of Columns
+ or - 3mm in 3,000
b)
Horizontal Members
+ or - 3mm from specified level at supports
c)
Section Discontinuity
+ or - 3mm
d)
Overall Dimension
+ or - 10mm in 30,000
e)
Connection to Concrete Bolts cast in rigidly Bolts cast in sleeves Projection of the bolt
f)
+ or - 3mm in any direction + or - 5mm in plan + 25 or - 5mm ends
Position of Column Bases Plan about axis + or - 5mm Level of base plate + or - 5mm
Rectification of work not constructed within the permissible deviations set out above will be to the approval of the S.O. and entirely at the expense of the Steelwork Contractor. Notwithstanding the above the positioning and levelling of all steelwork, the plumbing of stanchions and the placing of every part of the structure shall be to the satisfaction of the S.O.
7.19 Grouting At all places where steel members are subsequently required to transmit load to concrete, the latter shall be fair finished at the requisite level and if specified provided with anchor bolts in accordance with the drawings. The space between the concrete and steel shall be not less than 25mm and not more than 50mm unless otherwise specified or approved by the S.O. After the steelwork is set on steel packings in its final position, levelled and plumbed, and the grouting space thoroughly cleaned out, the holding down bolts and space beneath the base plate shall be filled with an approved premixed non-shrink cementitious grout mixed and placed in accordance with the manufacturers’ instructions. Where the use of liquid grout is impracticle the space shall be filled with semi-dry mortar composed of three parts sand, one part Portland Cement and an approved non-shrink additive, rammed in with a suitable tool against properly fixed supports. Semi-dry mortar shall only be used with the prior consent of the S.O. The grouting or packing shall be done by the Specialist.
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Section 7 - Structural Steelwork
7.20 Inspection The S.O. shall have full liberty at all reasonable times, to enter the Works where the steelwork is being fabricated or treated for the purpose of inspecting the work. Any work found to be defective or which is not in accordance with the drawings or this Specification, shall be made good or rejected. The Contractor is to allow for providing access for the S.O. to inspect or carry out any independent tests on the structure on site.
7.21 Subletting The Steelwork Contractor shall only be permitted to sublet the fabrication, treatment and erection of the structural steelwork with the prior approval of the S.O.
7.22 Required Information from the Contractor A summary of information required from the Contractor for approval is given in Table 7.3. Table: 7.3
Summary of Information Required From the Contractor for Approval
Item
When Required
Clause Ref (1)
Steel Tests Certificates
Before fabrication
7.2
Shop Drawings Calculations
Before fabrication
7.4
HSFG Tightening
At start of Contract
7.7
Welder Qualifications
Before fabrication
7.8
Welding Information
Before fabrication
7.8
Painting System
Before painting
7.16
Erection Sequence
At start of Contract
7.17
and
Process
Date Req'd
Note: (1)
This column will be completed at the start of the contract.
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Section 7 - Structural Steelwork
7.23 Fire Protection Fire rating to all structural steel shall be 2 hours. Blast clean all structural steel members to second quality (Preparation Grade Sa2.5) in accordance with BS EN ISO 8501 and BS EN ISO 8503. Apply approved primer at a minimum thickness of 75 microns DFT before applying intumescent coating. Apply intumescent to BS 476 and ISO 834 at the specified DFT for the individual member and according to manufacturer's specifications. Approved finishing coat is required for external exposed steelworks. Apply approved finishing coat at 60 microns DFT (minimum 50 to maximum 70 microns). The finish should be compatible with the intumescent coating. All intumescent material for use on the structural steel must be tested and assessed at a recognised accredited laboratory in accordance with approved national standards as a complete system. In addition, it shall be assess by a recognised independent thirty party and have an accreditation listing. The intumescent system has to comply with local Regulations and Building Codes and certified by BOMBA, Malaysia.
Typical Civil and Structural Engineering Specification for Sewerage Works Issue 01 / Rev 0 August 2008
7-12
Appendix - 7.1
APPENDIX 7.1 - TABLE 18 and 19 OF BRITISH STANDARD 5135 Table 18: Guidance on acceptance levels for butt joints Notation: t is parent metal thickness l is length of defect h is height of defect w is width of defect
Quality category
A
B
C
100% Minimum amount of volumetric nondestructive testing
10 % each weldera
10 % overalla
Cracks Not permittedb Lack of fusion Not permittedb Lack of root penetration
Not permittedb t ≤ 20 mm: l ≤ 10 mm h ≤ 2 mm t > 20 mm: l ≤ 15 mm
Not permittedb l ≤ 25 mm in any 100mm length of weld or h ≤ 0.2 t
h ≤ 2 mm Individual slag t ≤ 18 mm : l ≤ t/2 ≤ 6 mm t ≤ 20 mm: l ≤ 12 mm inclusions w ≤ 1.5 mm w ≤ 1.5 mm
D
None 100% visual only
Not permittedb l ≤ 25 % of length of weld (applicable only to joints welded from one side) l ≤ 25 mm in any Not applicable 100mm length of weld w ≤ 1.5 mm
t > 18mm ≤ 75 mm : t > 20 mm: l ≤ 20 mm l ≤ t/3 w ≤ 1.5 mm w ≤ 1.5 mm t > 75 mm: l ≤ 25 mm w ≤ 1.5 mm Linear group of Aggregate length ≤ 8 % of Any length of group Any length of Not applicable inclusions length of group which in provided adjacent group provided turn is not to exceed 12 t groups are separated by adjacent groups in length a distance of at least 4 are separated by a times the length of distance of at longest defect for t ≤ 20 least 4 times the mm and by a distance of length of longest at least 6 times the defect length of longest defect for t > 20 mm
Civil Work Specifications Final Document (June 2008)
App7-1
Appendix - 7.1
Table 18: Guidance on acceptance levels for butt joints (con’t) Quality category
A
B
Porosityc
Individual pores: ≤ 2 mm diameter. Localized: ≤ 2 % by aread for t ≤ 50mm then pro rata for greater thicknesses
Individual pores: ≤ 2.5mm diameter. Localized: ≤3 % by aread
Undercut
Intermittent, 0.5 mm maximum in depth
Intermittent, 0.5 mm maximum in depth
C
D
Individual pores: ≤ 3 mm diameter ≤ 0.25 t diameter. Localized: ≤ 4 % by aread
Surface porosity Individual pores: ≤ 3 mm diameter ≤ 0.25 t diameter Localized: ≤ 4 % by aread Intermittent, 0.5 Depth ≤ 0.1 t mm maximum in ≤ 1 mm depth l≤ 10 % of length of weld
a
When random volumetric non-destructive testing reveals unacceptable defects in a joint, two further joints in the group represented by this joint should be tested similarly. If the results on these two further joints are acceptable then the original weld should be repaired and retested by similar non-destructive means. If the repair is satisfactory then the group of joints should be accepted. If the non-destructive testing of the two further joints reveals unacceptable defects, each joint in the group should be non-destructively tested. Unacceptable defects should be repaired and retested by similar non-destructive means. b This does not mean that the whole joint is rejectable, merely that attention be given to the particular area, e.g. local repair or grinding without welding. c If found during ultrasonic examination, then check-radiography should be applied. d The area to be considered should be the length of weld affected by porosity times the maximum width of weld.
Table 19: Guidance on acceptance levels for fillet welds Quality category
A
Minimum amount of 100 % of weld surface non-destructive surface and 10 mm testing (either liquid of adjacent parent penetrant or magnetic metal each side weld particle testing) Cracks Not permitteda Lack of fusion Undercutc Intermittent, 0.5mm maximum in depth Fit-up Throat thickness
B Random 10 % of weld surface and 10 mm of adjacent parent metal each side of weld Not permittedab
C
D
Randomly 5 % of None weld surface and 10 100 % visual only mm of adjacent parent metal each side of weld Not permittedab Not permittedab
Intermittent, 0.5mm Intermittent, 0.5mm Some undercut 1 maximum in depth maximum in depth mm maximum in depth For partial penetration T-joints the results of inspection of joint preparation and fit-up to be recorded Total throat thickness to be not less than that specified
a
This does not mean that the whole joint is rejectable, merely, that attention be given to the particular area, e.g. local repair or grinding without welding b If cracks or lack of fusion are found, there may be a need to carry out up to 100% examination. c The acceptability of undercut should be at the discretion of the contractor's quality control department in consultation with the designer and any inspecting authority.
Civil Work Specifications Final Document (June 2008)
App7-2
Section 8 - Sewer, Force Mains, Pipelaying, Manholes and Appurtenances
Page 8.0
SEWERS, FORCE MAINS, PIPELAYING, MANHOLES AND APPURTENANCES .....................................................................................8-1 8.1
General for Pipeline .........................................................................8-1 8.1.1 Test Certificates ................................................................................... 8-1 8.1.2 Pipe Marking .......................................................................................... 8-1
8.2
Vitrified Clay Pipes ..........................................................................8-2 8.2.1 General ..................................................................................................... 8-2 8.2.2 Joints ........................................................................................................ 8-2
8.3
Reinforced Concrete Pipe (RCP) and Fittings...............................8-3 8.3.1 General ..................................................................................................... 8-3 8.3.2 Materials .................................................................................................. 8-3 8.3.3 Tests .......................................................................................................... 8-4 8.3.4 Permissible Variations in Dimensions ........................................ 8-4 8.3.5 Workmanship and Finish.................................................................. 8-4 8.3.6 Rejection .................................................................................................. 8-4 8.3.7 Joints ........................................................................................................ 8-5 8.3.8 Cementitious Lining ........................................................................... 8-5 8.3.9 Marking..................................................................................................... 8-5
8.4
Polyethylene Pipes (PE) and Fittings.............................................8-5 8.4.1 Materials .................................................................................................. 8-5 8.4.2 Solid Wall PE Pipes ............................................................................. 8-5 8.4.2.1 Sizes and Classes....................................................8-6 8.4.2.2 Fittings......................................................................8-7 8.4.2.3 Joints ........................................................................8-8 8.4.2.4 Quality Control and Quality Assurance Testing ...8-9 8.4.3 Profile PE Sewer Pipes ...................................................................... 8-9 8.4.4 Dimensions and Tolerances............................................................ 8-9 8.4.5 Fittings.................................................................................................... 8-10 8.4.6 Joints ...................................................................................................... 8-11 8.4.7 Mechanical Properties ..................................................................... 8-11 8.4.8 Quality Control Test .......................................................................... 8-12 8.4.9 Visual Inspection................................................................................ 8-14 8.4.10 Information to be Provided ............................................................ 8-14
8.5
Glass Fibre Reinforced Plastic (GRP) Pipes and Fittings ..........8-15
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Section 8 - Sewer, Force Mains, Pipelaying, Manholes and Appurtenances
8.5.1 Materials ................................................................................................ 8-15 8.5.2 Dimensions ........................................................................................... 8-16 8.5.3 Fittings.................................................................................................... 8-16 8.5.4 Joints ...................................................................................................... 8-16 8.5.5 Stiffness ................................................................................................. 8-17 8.5.6 Strain Corrosion Resistance ......................................................... 8-17 8.5.7 Quality Assurance Tests................................................................. 8-17 8.5.8 Information to be Provided ............................................................ 8-17 8.6
Unplasticized PVC Pipes and Fittings..........................................8-18 8.6.1 General ................................................................................................... 8-18 8.6.2 Joints ...................................................................................................... 8-18
8.7
ABS Pipe.........................................................................................8-19 8.7.1 Materials ................................................................................................ 8-19 8.7.2 Sizes/Classes....................................................................................... 8-19 8.7.3 Fittings.................................................................................................... 8-20 8.7.4 Joints ...................................................................................................... 8-20
8.8
Ductile Iron Pipes and Fittings .....................................................8-21 8.8.1 General ................................................................................................... 8-21 8.8.2 Manufacture and Testing ................................................................ 8-21 8.8.3 Process of Manufacture .................................................................. 8-21 8.8.4 Thickness, Diameter and Length ................................................ 8-22 8.8.5 Tolerances ............................................................................................ 8-23 8.8.6 Works Tests ......................................................................................... 8-23 8.8.7 External Coating ................................................................................. 8-23 8.8.8 Internal Lining ..................................................................................... 8-24 8.8.9 Fittings.................................................................................................... 8-24 8.8.10 Joints ...................................................................................................... 8-25 8.8.11 Marking................................................................................................... 8-26
8.9
Steel Pipes......................................................................................8-26 8.9.1 General ................................................................................................... 8-26 8.9.2 Testing .................................................................................................... 8-27 8.9.3 Dimensions ........................................................................................... 8-27 8.9.4 Straight Pipes ...................................................................................... 8-27 8.9.5 Specials .................................................................................................. 8-27 8.9.6 Joints ...................................................................................................... 8-27
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8.9.7 Protection .............................................................................................. 8-29 8.9.8 Lining ...................................................................................................... 8-29 8.9.9 Coating ................................................................................................... 8-29 8.9.10 Painting .................................................................................................. 8-30 8.9.11 Marking and Transportation .......................................................... 8-30 8.9.12 Repair of Lining and Coating ........................................................ 8-30 8.10
General for Pipeline Installation ...................................................8-31 8.10.1 Scope of Works .................................................................................. 8-31 8.10.2 Definitions ............................................................................................. 8-31 8.10.3 Dimensions of Pipes......................................................................... 8-32 8.10.4 Specialists, Inspection and Testing ........................................... 8-32 8.10.5 Tools for Pipe Installation .............................................................. 8-32 8.10.6 Handling, Storage and Protection during Transit ................ 8-32 8.10.7 Inspection at Time of Installation................................................ 8-33 8.10.8 Laying Diagrams ................................................................................ 8-33
8.11
Installation of Pipes .......................................................................8-33 8.11.1 General Installation Work ............................................................... 8-33 8.11.2 Pipe Laying ........................................................................................... 8-34 8.11.3 Closures and Short Sections ........................................................ 8-35 8.11.4 Pipe Bedding for Sewer Pipes...................................................... 8-35 8.11.5 Concrete Protection of Sewer Pipes.......................................... 8-36 8.11.6 Protection of Joints for Force Mains ......................................... 8-37 8.11.7 Tolerances of Alignment and Invert Levels ............................ 8-37
8.12
Special Laying Methods: Jacking.................................................8-37 8.12.1 Pipe Jacking - Procedures ............................................................. 8-37 8.12.2 Alternative Trenchless Pipe Installation Methods ............... 8-38 8.12.3 Type of Pipe Used for Jacking ..................................................... 8-38 8.12.4 Alignment Control and Tolerances ............................................ 8-39 8.12.5 Joints for Jacking Pipes ................................................................. 8-39 8.12.6 Joints Performance Test................................................................. 8-39 8.12.7 Jacking and Receiving Pits ........................................................... 8-39 8.12.8 Jacking Records................................................................................. 8-39
8.13
Changes In Line and Grade ..........................................................8-40 8.13.1 Deflection at Certain Joints ........................................................... 8-40
8.14
Stream and River Crossing...........................................................8-40
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8.15
Connection to Existing Sewer Mains ...........................................8-40
8.16
Manholes ........................................................................................8-41
8.17
Testing Pipelines ...........................................................................8-42 8.17.1 Testing – Gravity Sewers ...................................................8-42 8.17.2 Testing of Force Main (Hydraulic Testing)........................8-43
8.18
Sewer Inspection, Condition Assessment and Classification ...8-45
8.19
Test for Straightness .....................................................................8-45
8.20
Cleanliness of Sewers and Force Mains......................................8-45
8.21
Temporary Surfacing.....................................................................8-46
8.22
Liability in Pipe Installation...........................................................8-46
8.23
Maintenance in Pipe Installation Work.........................................8-46
8.24
Sewer Connections to Existing Properties..................................8-46
LIST OF TABLE Table: 8.1 – Pipe Diameter Vs Minimum Crushing Strength Table: 8.2 – Stiffness of PE Pipes Table: 8.3 – Sampling Procedure of PE Pipes Table: 8.4 - Stiffness of GRP Pipes Table: 8.5 – Dimensions of ABS Pipe Table: 8.6 – Classification of ABS Pipe Table: 8.7 – Nominal Diameter Vs Thickness of Wall and Lining of Pipes Table: 8.8 - Hydrostatic Test Pressure
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8.0 Sewers, Force Mains, Pipelaying, Manholes and Appurtenances 8.1
General for Pipeline
Included in this section is the supply and factory testing of pipeline materials for gravity sewers and force mains. Specifications are included for different materials for both gravity sewers and force mains. Unless otherwise specified vitrified clay for sewers ranging in size from 100mm diameter to 450mm in diameter and reinforced concrete pipe for sizes pipe shall be used 600mm and greater in diameter. The Contractor shall satisfy himself that the pipes included in his tender will be available to him in the specified quality and in the quantity to meet his construction schedule. Unless otherwise approved by the S.O., a single manufacturer or supplier shall supply each type of pipe and its related fittings. All pipes shall be design and manufactured to have a minimum expected life span of 50 years under the specified service.
8.1.1 Test Certificates The Contractor shall submit to the S.O. duplicate copies of test certificates, signed by the manufacturer giving the results of the factory tests on each pipe and special or batch of pipe and specials as required before dispatch and certifying that each item or batch of items complies with the requirements of the specification and the relevant standard. The cost of providing test certificates shall be deemed to be included in the Contract Rates.
8.1.2 Pipe Marking The following shall be clearly marked on each pipe and fitting delivered to site: a.
The date of manufacture
b.
The name and trademark of the manufacturer
c.
Length, diameter, branch diameter for tees and angles for bends
d.
The material and weight of the pipe or fitting
e.
The strength category that the pipe or fitting conforms to
f.
Factory test pressure (as relevant)
g.
Manufacturing standard compliance
h.
SIRIM or other certification logo as approved
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8.2
Vitrified Clay Pipes
8.2.1 General All vitrified clay pipes and fittings shall be in accordance with MS 1061 or BS EN 295 with required crushing as shown below: Table 8.1: Pipe Diameter Vs Minimum Crushing Strength Pipe Diameter (mm)
Minimum Crushing Strength (kN/m)
Class No.
150 225 300 375 450 500 600
24 36 48 45 54 60 72
160 160 120 120 120 120
Material used for manufacture of vitrified clay pipe shall comprise of blends of naturally available clays. All clayware pipes and fittings shall be tested at the factory after manufacture and shall satisfy all the performance requirements stipulated for Class Number 120 pipes and fittings in BS EN 295. Each pipe and fitting shall carry the SIRIM acceptance logo or equivalent. Test Certificates shall be provided. Pipes and fittings shall be transported to and stored at the Site in a satisfactory manner to prevent breakages. The Contractor will be at liberty to use pipe lengths up to the maximum shown in Table 2 of BS EN 295. Some shorter pipes with flexible joints may be required to permit the required levels, positions and lengths to be accurately obtained.
8.2.2 Joints The pipes shall be provided with pre-fitted `O' rings spigot/socket joints or skid-type sealing joints. Vitrified clay pipes shall be jointed strictly in accordance with the manufacturer's instructions. Spigots, sockets, rubber rings and all sealing faces shall be free from dirt and shall be coated with the manufacturer's lubricant during jointing. Rubber rings and vitrified clay pipes with pre-fitted sealant shall be properly stored out of direct sunlight prior to their use. Rings shall comply with BS 2494 and BS EN 682. The ‘O’ ring or fitted sealant shall be made of 100% natural rubber and shall not turn brittle in the sun or creep under pressure or deteriorate during transit or storage. It shall be able to be precisely fitted to provide a durable watertight and long lasting joint system.
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8.3
Reinforced Concrete Pipe (RCP) and Fittings
8.3.1 General Pipes shall be of reinforced concrete constructed by the centrifugal spun method or the vibro-cast method or type, size, strength and quality as indicated on the drawings or as specified. Pipe sections shall be in minimum lengths of 3m or as specified by the S.O., except where shorter lengths may be required to meet special conditions. The manufacturer shall supply certificates of strength. Pipe shall be in accordance with MS 881 or BS 5911 : Part 1 and the applicable provisions of these Specifications and internal diameters shall be as shown on the drawings. RCP and fittings from manufacturers with relevant ISO 9000 certifications only shall be acceptable.
8.3.2 Materials a.
Aggregates shall conform to the requirements for concrete aggregates as set forth in these Specifications. The maximum size of the coarse aggregates shall vary with the size of the clear opening between reinforcing bars or between the bars and the inside or outside surface of the pipe wall. The maximum size aggregate consistent with proper placing shall be used.
b.
Portland Cement shall conform to the requirements as set forth in BS EN 197-1. Ordinary Portland Cement shall be used unless otherwise indicated.
c.
Mix of concrete in which the aggregate shall be sized, graded, proportioned and thoroughly mixed in a batch mixer with such proportions of cement and water as will produce a homogenous concrete mixture of such quality that the pipe will conform to the test and design requirements of these Specifications.
d.
Placing of concrete shall be done in the forms by means of the centrifugal spun method or the vibro-cast method.
e.
Curing of concrete pipes shall be done by steam injection, mechanically controlled watering or by any other established method that will keep the pipe moist during the specified curing period.
f.
Reinforcement shall consist of hard drawn steel wire, steel wire fabric or steel bars. Hard drawn steel wire for concrete reinforcement shall conform to the requirements as set forth in BS 4482. Steel wire fabric for concrete reinforcement shall conform to the requirements as set forth in BS 4461 respectively.
g.
Placing of reinforcement shall be done in accordance with BS 5911 : Part 1.
h.
Design and reinforcement shall be of the size, and spacing to withstand the loadings specified in the Drawings.
i.
The contractor shall submit for approval detailed shop drawings of the pipes, joints, reinforcement, cage assemblies prior to manufacture of the pipe.
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8.3.3 Tests Concrete pipes may be tested by the S.O. by one or more of the following tests. The Contractor shall furnish without charge all necessary equipment and samples for making the tests. All tests shall be made in accordance with BS 5911 : Part 1. Any pipe tested shall not be used in the sewer mains. a.
Absorption Test is to determine the amount of moisture absorbed by the concrete.
b.
Three-Edge Bearing Strength Test may be made to determine the ultimate strength of the pipe and the works proof load which the pipe will withstand.
c.
Sand Bearing Test may be used in place of the three-edge bearing test to determine the strength of the pipe.
d.
Core or Cube Test may be used to determine the strength of the concrete in the pipe. Cores may be cut from the concrete of the pipe or test cubes cast from the concrete.
e.
Visual Inspection and Test may be made by the S.O. before and/or after delivery of the pipe, for the purpose of determining the placement of the reinforcement, the size, shape, fractures, spalls, honeycomb or other imperfections or damage. The Contractor shall notify the S.O. not less than 24 hours in advance of beginning manufacture of the pipe. The S.O. shall have access to all operations of the manufacture and may inspect and test any or all equipment, materials and operation used in the manufacturing, handling and curing of the pipe.
8.3.4 Permissible Variations in Dimensions Variations of the internal diameter of the pipe and other variations in dimensions shall conform to the requirements as set forth in BS 5911 : Part 1.
8.3.5 Workmanship and Finish Concrete pipe shall be substantially free from fractures, large or deep cracks, and surface roughness. The planes of the ends of the pipe will be perpendicular to their longitudinal axis.
8.3.6 Rejection Pipe shall be subjected to rejection on account of failure to conform to any of the specified requirements or on account of any of the following: a.
Fractures or cracks passing through the shell, except that a single end crack that does not exceed the depth of the joint shall not be cause for rejection. If a single end crack that does not exceed the depth of the joint exists in more than 10 % of the pipe inspected, however, the defective pipe shall be rejected.
b.
Defects that indicate defective mixing and moulding.
c.
Surface defects indicating honeycomb or open texture.
d.
Spalls deeper than half the depth of the joint or extending more than 100mm around the circumference or spalls smaller than half the depth of the joint or less than 100 mm around the circumference exist in more than 10 % of the pipe. Exposed reinforcement which indicates that the reinforcement is misplaced.
e.
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8.3.7 Joints All reinforced concrete sewer pipes shall have spigot and socket or rebated joints with rubber ring joint, or approved equivalent.
8.3.8 Cementitious Lining All Reinforced Concrete Pipe, unless otherwise shown, shall be lined during manufacture with a 12.5mm thick high sulphate resisting lining consisting of High Alumina Cement (one part), granite dust passing No. 100 BS Sieve (one part), and 2.5 parts of fine aggregate with sufficient clean water to ensure maximum density. Sulphate Resisting Cement shall be in accordance with BS 4550-6 and BS EN 14647. Lining and testing of lining shall be in accordance with BS 4550-6 and BS EN 14647. Plastic liner plate shall not be used
8.3.9 Marking In addition to the requirements of clause 8.1.2, circular pipe with elliptical reinforcement shall have the letter ‘T’ clearly on the inside at the top and bottom at the correct place to indicate the proper position when laid.
8.4
Polyethylene (PE) Pipes and Fittings
8.4.1 Materials The quality of the starting raw material shall closely monitored at the resin-manufacturing site. Certifications shall be produced by pipe and fitting manufacturer documenting important physical properties such as melt index, density, environmental strength crack resistance (ESCR), stabilizer tests and tensile strength. The resin shall stabilized against thermal oxidation. The resin shall supplied in either the natural state which is normally blended at the extrusion facility to add pecitized colour and UV stabilizers or in the pre-coloured form. The colour depends on the intended application and the requirements of the relevant authorised bodies. Carbon black is the most common pigment used for sewerage application. The materials used for sewer pipes and fittings shall come from a single compound manufacturer and shall be made from natural polyethylene (PE) compounds conforming to the minimum cell classifications as defined in BS 3412 or DIN 16961. Compounds that have different cell classifications from those specified shall also be acceptable when one or more properties are superior to those of the specified compound. The PE compound can be in the form powders, granules or pellets. Some carbon blacks or titanium dioxide about 2-3% shall be added as ultraviolet stabiliser that makes the pipe resistant to UV degradation. Other additives normally added are lubricants, antioxidants and pigments. Design of PE pipes and fittings shall be based on the use of sand backfill compacted to not more than 75% of maximum dry density. Pipes shall be designed to have an expected life span in excess of 50 years under the specified service.
8.4.2 Solid Wall PE Pipes
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Solid wall PE pipes to be used for sewerage application shall comply with material, workmanship and test requirements in accordance with MS 1058. PE solid wall pipe is available locally in diameters up to 1,0000mm and in standard lengths of 6m and 12m. Pipe size of 160mm or less may be flange jointed or electrofusion jointed. Solid wall PE pipe is classified by pressure rating with static working pressures up to 1.6MPa which is normal during servicing. Since PE pipes are flexible, the design of the pipe/trench system is critical. Compared to rigid pipes, the stability of flexible pipes relies more on the side support of the earth backfill around the pipe. Consequently, in an urban environment, where the side support may be removed during future adjacent construction of underground services, pipe failures could be more frequent. Ground conditions that do not provide good pipe support are not suitable for flexible PE pipe. Solid wall PE pipe are suitable for buried sewer and buried vacuum sewer installations. Butt fusion joints shall be used for solid wall PE pipe. Solid wall pipe for pressure main application shall be of minimum PN10 rating. The use of specific strength shall depend on the depth and nature of the soil as confirmed by the Qualified Person. Solid wall pipes for vacuum sewer shall be minimum PN8 and at least PN10 for heavy vehicle loading. 8.4.2.1 Sizes and Classes
The dimensions and tolerances of the PE pipe are determined and set during the sizing and cooling operation. The sizing operation holds the pipe in its proper dimensions during of the molten materials. For solid wall pipe, the process is accomplished by drawings the hot material from the die through a sizing sleeve and into a cooling tank. Sizing is accomplished by either using vacuum or pressure technique. Nominal Outside Diameter (OD) of solid wall PE is a numerical of size to the PE piping system other than flanges and components designated by the thread size. The nominal outside diameter is fixed and represented by a round number which is convenient for reference purposes. The internal diameter of solid wall PE, however, shall vary with the class of pipes depending on the pipe thickness. The increment is not constant and the sizing follows the adopted international standards for thermoplastic pipe for pressure application. Standard length of solid wall PE pipe indicates the overall effective length of the pipe. The standard length varies with the diameter of the pipes and generally is between 6m to 12m for 100-1000mm OD. The pipes normally can be cut on site using most types of saws. Class of solid wall PE pipes is determined by the material types, PE 80 and PE 100, which correspond to the level minimum design strength at 200C for up to 50 years. PE 80 and PE 100 show the capabilities of the pipes to withstand 80 bar (8MPa) and 100 bar (10MPa) of strength respectively. The maximum design stress is obtained applying a design coefficient of 1.25 to the strength.
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Solid wall PE pipe is normally available in various compounds of different density and this alters the allowable stress the pipe can stand. Higher the allowable stress means thinner wall for the same working pressure. Ring stiffness of 8 kN/m2 (8000MPa) is generally taken as the minimum stiffness for smaller diameter pipe. Hence PE 80 with typical resin density of 950 to 955 kg/m3 is recommended for use in pressure sewerage. The required working pressure as intended for the specific working and site conditions shall be achieved by increasing the wall thickness. The pipes at the joint, however, shall have the same pressure class to ensure the pipe bores align. 8.4.2.2 Fittings
Various fittings are available which increase the overall use of the solid wall PE pipe system. PE fittings may be injection moulded, fabricated or thermoformed. The following section briefly describes the operations of each technique. a)
Fabricated Fittings
Fabricated fittings for solid wall PE pipes are normally available 200mm diameter and above. Fabricated fittings can be constructed by joining sections of pipe, machine blocks or moulded fittings together to produce the desired configuration. Components shall be joined by heat fusion, hot gas welding or extrusion welding techniques. Use of either hot gas or extrusion welding for pressure service fittings is not recommended since the joint strength is significantly less than of a heat fusion joint. Fabricated fittings designed for full pressure service are joined by heat fusion and must be designed with additional material in areas subject to high stress. The normal practice is to increased wall thickness in high-stress areas by using heavy-wall pipe sections. The increased wall thickness may be added to the nominal Outside Diameter (OD) which provides for a full-flow nominal Inside Diameter (ID); or it may be added to the ID which slightly restricts ID flow. This is similar to moulded fittings that are moulded with a larger OD, heavier body wall thickness. If heavy-wall pipe sections are not used, the pressure rating of the fitting needs to be reduced accordingly. The lowest pressure rated component shall determine the operating pressure of the pipe system. Very large diameter fitting shall be handled with great care during unloading and installation. Precautions shall be taken to prevent bending moments that could stress the fitting during these operations. These fittings can be wrapped with reinforcement materials such as rubber or fibreglass for protection. b)
Injected Moulded Fittings
Injection moulded solid PE fittings can be manufactured in sizes trough various sizes. Typical moulded fittings are tees, 45O and 90O elbows, reducers, couplings, caps, flange adapters and stub ends, branch and service saddles, and self-tapping saddles tees. Very large parts may exceed common injection moulding equipment facilities so these are usually fabricated. c)
Thermoformed Fittings
Thermoformed fittings are manufactured by heating a section of pipe and then using a forming tool to reshape the heated area. Examples are sweep elbows, swaged reducers and forged stub ends. The area to be shaped is immersed in a hot liquid bath and heated to make it pliable. It is then removed from the heating bath and reshaped in the forming tool. The new shape shall be held until the part has cooled.
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d)
Electrofusion Couplings
Electrofusion couplings and fittings for solid wall PE pipe can be manufactured by either moulding in a similar manner as butt and socket fusion fittings or manufactured form pipe stock. A wide variety of couplings and other associated fittings are available. Electrofusion fittings are manufactured with coillike integral heating element. These fittings shall be installed utilizing a fusion processor which provides the proper energy to provide a fusion joint stronger than the joined pipe sections. 8.4.2.3 Joints
Solid wall PE pipes shall be jointed using reliable approved methods. The common methods for jointing are as follows: a)
Thermofusion Welding
Thermofusion welding is also known as fusion welding. This method uses heated tools to weld the joint faces together and can be applied to specially made mould socket fittings for spigot-socket jointing and also to those made for butt jointing. Butt fusion joint is suitable for jointing of the solid wall PE pipes. It is carried out by heating the faces of the components to be joined against a heated flat plate which are usually coated with PTFE. Theses faces are then brought together under control pressure. Butt welding normally leaves a raised bead on the joint inside the pipe which will interfere with the flow. The internal bead but shall be removed using suitable tools before inspection. Spigot-socket joint is performed with one end of the pipe opened up to act as the socket of a moulded fitting and thereafter the butt fusion welding is carried. b)
Electrofusion
Electrofusion is simpler to carry out than butt fusion but it is applicable for small diameter of solid wall PE pipe normally up to 315mm only. The heating and the timing operations are all automatically taken by a control unit of the following procedures: -
Electrofusion coupling slipped over the ends of the pipe to be joined
-
Resistance wires in the coupler are heated by a controlled electric current
-
The coupler and pipe are melted and fused to each other
The setback of this method of jointing its greater cost compared to thermofusion welding. c)
Flange Joint
Flange joint can be used where require for jointing to fitting or pipes of other material and most commonly used for larger diameter pipes. It consists of either a full face or stub flanges welded to the pipe or alternately can be formed on the pipe. The rotational flexibility provided by this type of jointing is compensated by the longitudinal flexibility of the PE pipe. d)
Mechanical Metal Coupling
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Mechanical metal couplings do not provide the strength or long-term performance as compared to a properly made fusion joint. This jointing method is normally considered for repair operations. There are wide ranges of small diameters plastic pipes e.g. acetal and GRP fittings use mechanical (compressed rubber seal) joints. 8.4.2.4 Quality Control and Quality Assurance Testing
Quality shall be engineered into pipe product during the entire manufacturing process of solid wall PE pipes and fittings. The three (3) phases of quality control for the pipe manufacturer involve the incoming raw material, the pipe or fitting production and the finished products. Combination of all three areas can ensure that the final product fulfils the requirements of the specification to which it was made. Testing of the incoming resin is crucial and the first step in the quality control program. The resin shall be checked for contamination, melt index, density, tensile strength and environmental stress crack resistance (ESCR). Any resin that does not meet the raw material specification shall not be used for the production. During the manufacturing stage, the pipe producer shall routinely perform quality assurance tests on samples. This can verify that proper production procedures and controls are implemented during operation. Once the product has been produced, it shall undergo a series of quality control tests to ensure that it meets the minimum specifications as required. Quality inspections for solid wall PE pipes and fittings typically include knit line strength, voids, dimensions and pressure tests. A knit line is formed when the shot flows around a core pin and joins together on the other side. Voids can form from materials shrinkage during cooling, particularly in heavier sections. Voids can be detected non-destructively by using x-ray scans. If this is not feasible, samples shall be cut into thin sections and inspected visually.
8.4.3 Profile PE Sewer Pipes A profiled wall pipe consists of an outer ribbed or corrugated wall fused to a smooth inner wall with sizes based on controlled inside diameter. The ribs or corrugation shall be normally either aligned circumferentially or helically. These corrugated or ribbed profiles optimize the pipe ring stiffness to weight ratio and improve static load bearing capacity. The pipe shall be designed with double-wall profile or triple-wall profile. It must be able to withstand high pressure jetting up to 120 bars as commonly used for sewer servicing. Corrugated PE pipe is available normally in a range of size from 100mm to 3000mm nominal diameter and in standard 6m lengths. The standard joint is normally flexible spigot-socket with rubber seal. Only approved PE pipes from licensed manufacturer shall be used for gravity sewers especially where special circumstances maximize the benefit of such pipes.
8.4.4 Dimensions and Tolerances The average inside diameter of the pipe shall meet the requirements given in Table 2 of DIN16961. The average inside diameter can be measured by taking a series of at least six (6) inside diameter measurements at equally spaced intervals using appropriate measuring devices such as calipers, inside micro meters or telescoping gauges and calculating the average inside diameter by taking the average of all theses measurements.
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The finished dimensions of all pipes, fittings-couplings, specials or other components shall be compatible with their assembly into a completed system satisfying all requirements of the Contract and, in particular, the specified requirements for water tightness and joint flexibility. The dimensions of PE pipes shall be to DIN 8074/75 for pipes up to and including 1000mm nominal diameter. For pipes exceeding 1000mm nominal diameter, dimensions and tolerances shall be as given below. Profile wall pipes shall comply with the dimensional tolerances of DIN 16961. a.
Pipe Diameter for PE Pipe, the Contractor shall state the “manufacturing size” which is to be supplied. The “manufacturing size” shall be the target internal pipe diameter to which the manufacturer works and shall not differ from the specified nominal internal diameter by more than ± 1%. A manufacturing tolerance of ± 1% deviation from the “manufacturing size’ is permitted for pipes up to and including 600mm nominal diameter, and of 0.5% for pipes of nominal diameter greater than 600mm.
b.
Standard lengths shall be 3 or 6 m and at least 90% of pipe supplied, other than specified specials, shall be of standard length. The remaining pipes shall have lengths of not less than 1.5m. Where the length of special pipes is specified a tolerance of ± 25mm will be allowed on the specified length.
Deviation from straightness of the bore of the pipe shall not exceed 0.3% of the effective length of the pipe or 15mm whichever is the smaller. This requirement shall NOT be limited to the straightness of the pipe when measured at its place of manufacture.
8.4.5 Fittings Bends and Fittings shall be equal or superior in performance to the corresponding pipes. Mitred bends and fittings or mitring at sections of straight pipes shall be manufactured from pipes which have passed the appropriate hydraulic test and shall have a smooth internal surface free from weld run projection. The angle of deviation of bends shall be within ± 1° of the specified angle where the nominal diameter does not exceed 600mm and within ± 0.5° where the nominal diameter is greater than 600mm. The overall length of fittings shall be within ± 10 mm of that specified or stated in advance by the manufacturer, and the length from the point of inter-section of junctions to any end shall be within ± 5 mm of that specified or stated in advance. All welds shall be in accordance with approved standards. Dimensions of bends and fittings shall comply with the angle of deviation and tolerances on length set as given above. Only qualified and competent personnel shall carry out weld on pipes and manufacturer shall produce certificate and other related documents as evidence.
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8.4.6 Joints Joints of PE pipes and fittings shall be provided with bell and spigot joints suitable for external extrusion welding. In addition for pipes greater than 1000 mm diameter, the joints shall be internally welded. The method of extrusion welding shall be to the S.O.’s approval. Friction welding will not be permitted. The completed welded joints shall provide a smooth internal bore to the pipe, which shall be accurately aligned and without internal projections due to weld run or distortion. The completed joints shall have a longitudinal strength of not less than that of the main pipe barrel, i.e. a weld factor of not less than 1.0 and shall be capable of withstanding the specified internal test pressure. Alternatively, PE pipes and fittings with a nominal internal diameter less than 1000 mm shall be jointed using a socket-spigot assembly sealed by an elastomeric sealing ring. The socket or bell shall be formed integrally with the barrel of the pipe or fitting, and the complete joint shall be capable of accommodating a relative longitudinal movement (telescopic draw) of not less than 1% of the effective length of the longer pipe or fitting at any point. Elastomeric gaskets shall be manufactured from material that complies with the physical property requirements specified in DIN 16961 and shall not leak. The dimensions shall be in accordance with the manufacturer’s standard design dimensions and tolerances. The elastomeric gasket shall be the sole element depended upon to make the joint flexible and watertight under all combinations of joint and gasket tolerances. The gasket shall be a continuous ring in nature. The joint components shall be of such design that they will withstand the joining forces by the compression of the elastomeric gasket without cracking or fracturing. All surfaces of the joint upon or against which the gasket may bear shall be smooth and free from cracks or fractures and imperfections that could adversely affect the performance of the joint. Where a spiral-winding seam exists, it shall not be regarded as a crack as long as it shows evidence of a continuous bond. Lubricants, if required, shall be suitable for lubricating the parts of the joint in assembly. The lubricants shall have no adverse effect on the gasket and PE pipe materials.
8.4.7 Mechanical Properties The stiffness of the pipes when defined as EI/D3 where E is the bending modulus of the pipe wall in the circumferential direction (N/m2), I is the moment of inertia of the pipe wall per unit length (m4/m) and D is the nominal internal diameter of the pipe (m), shall not be less than the following: Table 8.2: Stiffness of PE Pipes Stiffness 2
Initial stiffness N/m Stiffness at 24 hrs N/m2
Light Duty
Medium Duty
1,250 450
1,500 675
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Stiffness testing shall be carried out in accordance with the methods set in DIN 16961 Part 2, ASTM D-2412 or similar. The applied tests load per unit length of pipe shall be that corresponding to a pipe deflection of 3% of the diameter when the pipe stiffness is taken as the 24 hour value specified above. The initial stiffness shall be calculated by measuring the deflection immediately after application of the test load and using the formula EI/D3 = 0.019 load/deflection. The test shall then be continued for 24 hours, at the end of which time the deflection of the pipe shall not exceed 3% of the diameter. Pipes used for the stiffness test shall not be included in any delivery for incorporation into the works. Pipe deflection on PE Pipe, on completion of a 24 hours stiffness test, the test load shall be progressively increased until a pipe deflection of 20% the diameter is reached. The pipe shall then sustain this load for a period of one minute without visible signs of damage or distress. The load corresponding to this deflection shall be recorded and notified in the pipe test report.
8.4.8 Quality Control Test Prior to initial commencement of delivery, and prior to commencement of delivery following any change in design, materials or methods of manufacture the following shall be carried out: -Inspection of manufacturer’s works -Deflection to failure test The following tests shall be carried out regularly at the frequencies specified in Table 8.2: a)
Pipe Compression Strength
There shall be no evidence of splitting, cracking or breaking when tested in accordance with DIN 16961. One specimen of PE pipe, about 300 mm in length if NPS-18 or over, or about 150 mm in length if under NPS-18, shall be flattened between parallel plates in a suitable press until the distance between the plates is 40% of the original outside diameter of the pipe. The rate of loading shall be uniform and such that the compression is completed within 2 to 5 minutes. For closed profile pipe, the loading force shall rise continuously and the specimen shall retain a smooth, elliptical form up to the point of 60% compression. Upon removal of the load, the specimen shall be examined for evidence of splitting, cracking, or breaking. For closed profile pipes only, test records or loading charts shall be examined for any discontinuity in the acceptance of the load by the specimen. Small tears initiated at the cut end of the corrugation shall not constitute failure when they are less than or equal in length to 10% of the nominal diameter of the individual test specimen, up to a maximum length of 75 mm. If the specimen fails by splitting, cracking or breaking or in the case of closed profile pipe exhibits discontinuous acceptance of the load, two more specimen shall be tested. If both pass, the material shall be acceptable. If one the retest specimen fails, the materials shall be rejected. b)
Pipe Impact Resistance
Test specimen shall be cut from the sample and numbered. The cut shall be square and free form large chips or other imperfections. The length of the specimen shall be between 300 mm and 325 mm. For spirally corrugated PE pipe samples, the sample length may vary such that samples are of sufficient length to have included at least three full corrugation profiles. After conditioning the specimen in accordance to the requirement, five specimens shall be tested. Test impact energy shall be as specified. The impact energy shall occur on top of the corrugations, with the tup striking at the centre of the corrugation crown. When two or more specimens fail, the product
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does not meet the impact requirement. When only one specimen fails, an additional five specimens shall be tested. To meet the specified impact requirement, none of the five specimens shall fail. Failure shall be defined as any crack or split on the inside or outside of the waterway wall that was created by the impact and that can be seen by the naked eye. Separation of the corrugations from the waterway wall shall constitute a failure. Damage to the waterway wall shall constitute a failure but cracking or breaking of corrugations shall be acceptable. Lighting devices shall be used to assist in the examination for cracks and splits in the waterway wall of the pipe specimen. c)
Air Tightness of Spirally Wound Pipe
Each length of PE pipe shall be tested for air tightness for the minimum dwell period specified in DIN 16961. The following shall the test procedure: i)
The pipe ends shall be sealed with a suitably restrained closure.
ii)
The pipe shall be pressurized with air to 24.1 kPa (3.5 psi) and the air source cut-off. Pipe may be pressurized above this level before the dwell period commences.
iii)
Timing of the dwell period shall commence and monitored
iv)
If the pressure falls below 23.3. kPa within the designated test period, the pipe shall be rejected.
d)
Weld Integrity of Welded Bells and Spigots
Each weld connecting bells or spigots, or both, to pipe shall be checked or integrity and continuity by air testing or alternatively, by subjecting the weld to an industry-accepted test such as spark testing or ultrasound testing. Test frequency and procedure shall be in accordance with the manufacturer’s standard practice. e)
Pipe Stiffness
Where the number of units produced in batches, the sampling procedures shall be in according to the following table: Table 8.3: Sampling Procedure of PE Pipe
No. of unit in batch
No. of unit in first sample
0-25 26-150 151-280 281-500 501-1200
2 5 8 13 20
No. of Defective unit in sample Accept Reject batch batch 0 0 0 1 2
1 2 3 4 5
No. of unit ins second sample 5 8 13 20
No. of Defective in both sample Accept Reject batch batch 1 3 4 6
2 4 5 7
The second samples are only taken where the number of detective units in the first sample lies between the numbers stipulated for acceptance or rejection of the batch. In no case shall sample unit founds defective be included in accepted batch. Batch is defined as a number of units of a particular specification, size or stiffness produced under uniform conditions during one continuous production
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period by the same process. For the purpose of Batch definitions, the continuous production period shall not exceed 24 hours: within this limit any size batch may be chosen. The unit tested in accordance with the requirements of this Clause shall in every respect be representative of the units supplied for incorporation into the works. The S.O. or his designated Representative shall be permitted, at all reasonable times, to visit the place of manufacture for the purpose of witnessing any of the above tests.
8.4.9 Visual Inspection Checks of dimensional accuracy will be carried out by the S.O. or his Representative as required, both at the place of manufacture and on site. Any units founds at any time failing to meet the specified dimensional, or quality criteria, shall be either be destroyed immediately or indelibly marked as rejected, and removed from the site. Whether or not there shall exist any physical evidence of damage any pipe which has undergone a deflection of more than 5% at any time will be automatically rejected and shall be clearly and indelibly marked as such. If on site pipes so affected shall immediately be destroyed or removed from the site.
8.4.10 Information to be Provided The Tenderer shall provide with the Tender the following information to the S.O. wherever the use of such pipes are specified or otherwise proposed to him. Prior to manufacture of any items, the Contractor shall inform the S.O. of any changes to this information. a.
Name of manufacturer and address of factory at which units are to be made.
b.
In the case of pipes or components made under license, the name and address of the company granting the license.
c.
Date of manufacture of pipe or date coding
d.
Whether pipe manufacture is already subject to independent quality control, inspection and certification procedures. (Such as the SIRIM acceptance logo or equivalent)
e.
Designation of any national or international specifications normally worked to. (If other than BS or ASTM a copy of the specification should be provided).
f.
Name and address of polyethylene manufacturer. In addition the following information regarding the polyethylene shall be provided, from the manufacturer: 1.
General description, name and type
2. 3.
Details of any pigments, stabilizers fillers, modifiers and other additive incorporated into the material Density (DIN 53479 or similar)
4.
Melt index (DIN 53735 or similar)
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5.
Yield stress, elongation at yield, ultimate tensile strength and elongation at break (DIN 53455, ISO RS 27 or similar)
6.
Coefficient of Thermal linear expansion (DIN 52328, ASTM DS96 or similar)
7.
Flexural Modulus (DIN 53452 or similar)
8.
Creep rupture strength (DIN 8075)
The pipe manufacturer will be required to provide evidence of continuing quality control procedures to ensure that the above characteristics of the material are maintained within the ranges stated by the polyethylene manufacturer and required by the pipe manufacturer:g.
Actual stiffness of pipes offered.
h.
Details of pie or component design.
i.
Method of manufacture to be used.
j.
Full details of the proposed jointing systems, including materials to be used, equipment required and full instructions for jointing.
Any changes to any of the above matters which are proposed to take place before the manufacture and supply of pipes for this Contract are completed shall notify the S.O. who may withdraw his approval of the manufacturer if not satisfied with the new arrangements.
8.5
Glass Fibre Reinforced Plastic (GRP) Pipes and Fittings
8.5.1 Materials a.
Resins used in the manufacture of pipe and fittings shall comply with the requirements of BS 3532 for polyester resin system or of BS EN 61558 for expoxide resin systems, and finished product shall in addition conform to BS EN ISO 5210 and BS EN ISO 5211.
b.
Glass fibre reinforcement shall be type “E” glass which satisfies the following specifications: -
Glass fibre roving BS EN 14020
-
Glass fibre chopped strand
-
Glass fibre woven fabric BS 3396
-
Glass fibre woven roving fabric BS 3749
Surface tissues for the inner and outer layers shall incorporate either type “C” glass, synthetic organic fibres or type “E” glass. c.
All aggregates, inert fillers, additive and colorants shall be used in accordance with BS EN ISO 5210 and BS EN ISO 5211.
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d.
Preformed thermo-plastic liners, if used, shall comply with BS 3505 or BS 3506 for unplasticised PVC liners and BS 4991 for polypropylene liners. The minimum liner wall thickness shall be 1.5mm.
8.5.2 Dimensions a.
The finished dimensions of all pipes, fittings, couplings and other components shall be compatible with their assembly into a completed system satisfying all the requirements of the Contract and of BS 5480 : Part 2 where applicable.
b.
Pipe Diameter for GRP Pipe, the Contractor shall state the “manufacturing size” which is to be supplied. This “manufacturing size” shall be the target internal pipe diameter to which the manufacturer works and shall not differ from the specified nominal internal diameter by more than -3.5% or + 1%. A deviation from the “manufacturing size” is permitted by limited to the tolerances specified as follows: + 1.5mm for pipes up to and including 150mm nominal diameter. + 3mm for pipes over 150mm up to and including 600mm nominal diameter.
c.
Effective length of pipe shall be as defined in BS 5480 : Part 1. Effective lengths acceptable are 3m and 6m unless specified otherwise on the Drawings. 95 % of all pipes supplied in any one diameter category shall conform to these effective lengths with a tolerance of + 25mm. The remaining pipes shall have the lengths of not less than 1.5 metres.
d.
All pipes shall fall within the Out-of-Square limits specified in BS 5480 : Part 1.
e.
The deviation from straightness of the bore of the pipe shall not exceed 0.3% of the effective lengths of the pipe or 15mm, whichever is the smaller. This requirement shall NOT be limited to the straightness of the pipe when measured at its place or manufacture.
8.5.3 Fittings a.
All fittings made from GRP, such as bends, tees, junctions and reducers, shall be equal or superior in performance to pipes of the same classification. All fittings shall be smoothly finished internally and comply with the dimensional tolerances stated in BS 5480: Part 1.
b.
Fittings made from materials other than GRP may be used provided they have compatible jointing systems and are equal or superior in performance to the GRP pipe of the same classification. Where applicable, such fittings shall comply with the relevant British Standards or, if these are not available, they shall fall within the same tolerance as those specified for GRP fittings above. In this respect, the Contractor shall provide the S.O. with a copy of the manufacturer’s specifications when proposing the use of fittings made from materials other than GRP, and he shall obtain prior approval of the S.O. for the incorporation of such fittings into the works,
8.5.4 Joints a.
Joints may be rigid or flexible (mechanical)
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b.
Rigid joints such as flanged joints, butt and overwrap, socket and spigot with bonding compound, screwed joints, etc. shall be equal or superior in performance to pipes of the same classification in both the circumferential and the longitudinal directions.
c.
Flexible (mechanical) joints such as rolling or restrained ‘O’ ring or clamped joints shall be equal or superior in performance to pipes of the classification of the main pipe barrel in the circumferential direction only, up to the limits of angular deviation or straight draw indicated by the manufacturer of the joint.
8.5.5 Stiffness The stiffness of the pipe when defined as EI/D where E is the bending modulus of the pipe wall in the circumferential direction (N/m2). I is the moment of inertia of the pipe wall per unit length (m4/m) and D is the nominal internal diameter of the pipe (m), shall not be less than the following: Table 8.4: Stiffness of GRP Pipes
Initial Stiffness (N/m2)
Light Duty 1,250
Medium Duty 1,500
Initial Stiffness shall be tested in accordance with Appendix J of BS 5480 : Part 2.
8.5.6 Strain Corrosion Resistance All pipes supplied and used in this Contract shall fulfill the strain corrosion resistance requirements specified in 5480 : Part 2. The Contractor shall produce documentary evidence of such compliance if requested by the S.O.
8.5.7 Quality Assurance Tests Testing for initial stiffness and leakage shall be carried out using double sampling procedures stipulated in BS 6001 for attaining a maximum of 10 % defective at an inspection level of S3 as described therein. The units used for testing shall be representative of the units supplied for incorporation into the works. a.
Stiffness Test, the initial stiffness of the pipe shall be determined in accordance with Appendix J of BS 5480: Part 2.
b.
Leakage Test, the pipe shall be able to withstand a hydrostatic pressure of 150 kPa without leakage when tested in accordance with Appendix G of BS 5480: Part 2.
Checks on dimensional accuracy will be carried out by the S.O. or his Representative as required, both at the place of manufacture and on site. Any units found at any time failing to meet the specified dimensional tolerances described in the Clause on Dimensions for GRP Pipes shall be either destroyed immediately or indelibly marked as rejected, and removed out or the site.
8.5.8 Information to be Provided The Tenderer shall provide the following information to the S.O. when submitting his tender.
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a.
Name of manufacturer and address of factory at which units are to be made.
b.
In the case of pipe or components made under license, the name and address of the company granting the license.
c.
Whether pipe is already subjected to independent quality control, inspection and certification procedures (such as the SIRIM acceptance logo or equivalent). Designation of any national or international specifications normally worked to (if other than BS or ASTM a copy of the relevant specification should be provided).
d.
f.
Specifications of materials used in manufacture of the GRP pipe and the sources of these materials. Also state details of any pigments, stabilizers, filters, modifiers and other additives used.
g.
Details of the pipe/component design.
h.
Description of the manufacturing process
i.
Physical properties of the finished product as follows : 1. 2. 3. 4. 5. 6.
Initial Hoop Tensile Strength Initial Longitudinal (Axial) Tensile Strength Flexural Modulus Coefficient of Thermal Linear Expansion Density or Specific Gravity Stiffness
Prior to manufacturer and supply of any item, the Tenderer if successful, shall notify the S.O. of any changes to the information that he has provided. The S.O. may in consequence of this withdraw his approval of the proposed manufacturer if he is not satisfied with the new arrangements.
8.6
Unplasticized PVC Pipes and Fittings
8.6.1 General Unplasticized PVC pipe shall not be used for main sewers. The use of uPVC shall be restricted to house connection sewers. Where permitted to be used, unplasticized PVC pipes, joints and fittings shall comply with the relevant provisions of BS 3505, BS 4514, BS 4660, BS 5481, AS 2032 or equivalent approved standards and codes of practice with respect to the handling, transportation and storage of uPVC pipes and fittings. Where long term storage racks are to be provided, the racks shall be built to accommodate four to seven layers of pipe, depending on the diameter and wall thickness of the pipes. Reference shall be made to BS 5955: Part 6 for further guidance on the use of uPVC pipes and fittings.
8.6.2 Joints
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All uPVC pipes shall be cut using only methods and tools approved by the S.O. Cut pipe ends shall be chamfered and cleaned of any burrs prior to jointing. Joints shall be made with solvent cement unless otherwise shown on the Drawings or as directed by the S.O. Solvent cements for jointing uPVC pipes and the method of jointing shall comply with BS 4346, Part 3 or AS 2032 and the following: (a)
For laying of a buried pipeline, the solvent jointed pipe shall be long enough to ensure a sealed joint.
(b)
For joints which have a rubber ring supplied integrally with the pipe, the fitting shall not be used if the ring is displaced, and
(c)
For pipes and fittings complying with BS 4660, solvent cement may comply with BS 6209. Unsatisfactory joints shall be re-made before proceeding with further pipelaying.
8.7
ABS Pipe
8.7.1 Materials Material compositions of ABS pipes consist of a copolymer of the monomers acrylonitrile, butadiene and styrene. For pipe applications for pressure sewerage system, appropriate quantities of each monomer shall be selected to optimise the performance properties of tensile strength, chemical resistance, ductility and weatherability. Material suitable for pressure pipe applications shall be Type 12142 in conformance with MS ISO 2580-1.
8.7.2 Sizes/Classes Nominal size (DN) shall be used as a numerical designation of the diameter of ABS pipe. The ABS pipe without couplings shall conform to the dimensions recommended in MS 1419:Part 1-1997 as given in Table 8.4 below.
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Table 8.5: Dimensions of ABS Pipe Nominal Size (DN) 10 15 20 25 32 40 50 80 100 150 200
Mean Outside Diameter, Dm Min Max 17.0 17.3 21.2 21.5 26.6 26.9 33.4 33.7 42.1 42.4 48.1 48.4 60.2 60.5 88.7 89.1 114.1 114.5 168.0 168.5 218.8 219.4
Pipe lengths show the standard overall length of the pipe, exclusive of coupling, of 6 + 0.05, -0m. All measurements shall be adjusted to an equivalent length at 20oC. The ABS pipe can be cut at site to the desirable length. However, care must be taken to ensure squareness of cut ends. Classes of ABS for force main are defined according to maximum static working pressure at a pipe material temperature of 20oC, as Table 8.5 below: Table 8.6: Classification of ABS Pipe Class of Pipe Class 4.5 Class 6 Class 9 Class 12 Class 15 Class T
Maximum Static Working Pressure, Mpa 0.45 0.60 0.90 1.2 1.5 1.2 after threading
8.7.3 Fittings Purpose made ABS fittings shall be used for making of junction connections and shall be suitable for pressure applications.
8.7.4 Joints The methods of jointing ABS pipes shall be one of the following : 1. 2.
Spigot-socket with solvent cement welding joint Stub flange joint with flange solvent cemented onto spigot end
The jointing of ABS pipe shall be carried out only by specially trained jointers. Solvent cement shall consist of one or more solvents and a sufficient quantity of base ABS material dissolved in the solvents to give the cement the body and consistency required for proper application. Inert fillers shall be used to control shrinkage during drying.
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8.8
Ductile Iron Pipes and Fittings
8.8.1 General Ductile Iron pipes and fittings shall comply with the requirements of BS 4772, BS EN 598 and BS EN 545. All pipes and specials shall be provided with a zinc spray coating and a bituminous varnish at the factory before delivery to Site. All pipes and specials shall be hydraulically tested at the factory after manufacture to a test head as given in Clause 8.8.5. The ends of each pipe and special shall be suitably protected against damage during transit to the Site by hessian wrapping or other superior means of protection. All flanges shall have wooden discs securely bolted on and the bolts used for this purpose shall be expendable and additional to those provided for subsequent permanent jointing. Joints shall be stored in hessian sacks and protected against sunlight until required for use.
8.8.2 Manufacture and Testing The manufacture and testing of ductile iron pipes and fittings shall comply with the current edition of BS 545, BS 598 and BS 969 unless otherwise specified. Pipework shall generally be lined internally with cement mortar and coated externally with a zinc spray coating and a bituminous varnish. Ends of pipes and fittings shall generally be socket and spigot suitable for forming flexible joints of the "push-in" type or "mechanical" type. Flanged ends where specified shall be suitable for jointing to valves and flanged pipework. Iron to be used for castings shall be made from pig iron or molten iron, iron or steel scrap, with such ferro-alloy and other additives as shall be necessary to produce in the resultant castings, a ductile iron complying with the mechanical properties as specified in Table 1 of BS 4772. Before dispatch of the Goods to the Site, the suppliers shall forward to the S.O., results of all specified tests and copies of test certificates stating that the pipes and fittings comply fully with the requirements of the Contract.
8.8.3 Process of Manufacture Ductile iron pipes shall be manufactured by one of the following process :(a) (b) (c) (d)
centrifugal casting in lined or unlined metal moulds, centrifugal casting in sand moulds, casting in sand moulds, casting in metal moulds.
Ductile iron fittings shall be manufactured by one of the following processes :(a) casting in sand moulds, (b) casting in metal moulds. "Sand" shall include mineral based materials used in the foundry trade irrespective of the type of bonding agent used. After casting, pipes and fittings may be subjected to heat treatment in order to achieve the required mechanical properties.
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Pipes and fittings shall be sound and free from surface or other defects likely to be detrimental to their use. Cracks and tears are specifically excluded from repair. Castings showing slight surface imperfections inseparable from the method of manufacture and in no way affecting their use, shall be accepted. On his own responsibility, the manufacturer may remedy such defects in a suitable manner. Subject to the S.O.'s approval, minor cavities and certain defects may be repaired by a proven process such as welding. Castings shall be capable of being cut, drilled, tapped or machined. If the S.O. considers that their quality does not comply with this requirement, Brinell hardness tests shall be carried out on them in accordance with BS 240:Part 1 except that the period of application shall be 15 + 1 seconds. The superficial hardness shall not exceed 250 HB for centrifugally cast pipes and 250 HB for all other castings.
8.8.4 Thickness, Diameter and Length The nominal and outside diameters and thicknesses of the wall and cement mortar lining of pipes and fittings shall be as shown in the Table below unless otherwise stated: Table No. 8.7: Nominal Diameter Vs Thickness of Wall and Lining of Pipes Nominal Diameter DN (mm) 1200 1100 1000 900 800 700 600 500 450 400 350 300 250 200 150 100 80
Outside Standard Wall Diameter Thickness OD (mm) (mm) 1253 1150 1048 945 842 739 635 532 480 429 378 326 274 222 170 118 98
15.3 14.4 13.5 12.6 11.7 10.8 9.9 9 8.6 8.1 7.7 7.2 6.8 6.4 6.3 6.1 6
Cement Nominal Thickness
Mortar (mm) Lining Minimum Minimum Mean Value at A Value Point
6.0 6.0 6.0 6.0 6.0 6.0 5.0 5.0 5.0 5.0 5.0 5.0 5.0 5.0 5.0 5.0 5.0
5.5 5.5 5.5 5.5 5.5 5.5 4.5 4.5 4.5 4.5 4.5 4.5 4.5 4.5 4.5 4.5 4.5
4.5 4.5 4.5 4.5 4.5 4.5 3.5 3.5 3.5 3.5 3.5 3.5 3.5 3.5 3.5 3.5 2.5
Pipes shall be supplied in standard lengths of between 5 and 6 metre.
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8.8.5 Tolerances (a)
Tolerances on standard mass
The supplier shall specify the standard masses of pipes and fittings for each type of joint. These shall be calculated using the nominal mass of 7050 kg/m3. The tolerances on the standard mass shall be in accordance with BS 4772. (b)
Tolerances on dimensions
The supplier shall specify the dimensions of pipes and fittings for each type of joint. The outside diameter of pipes is fixed as a function of the nominal diameter and is independent of the pipe wall thickness which shall be changed only by modification in relation to forces acting in each point of the castings, particularly to local stresses induced by internal pressure. Increases or decreases in wall thickness of fittings may be obtained by modification to either the outside or inside diameter. The tolerances on diameter, length, thickness, ovality and straightness shall be in accordance with BS 4772.
8.8.6 Works Tests Before being lined or coated, each pipe and fitting shall be hydrostatically tested at the manufacturer's works in accordance with BS 4772. The hydrostatic test pressure shall be as follows: Table No. 8.8: Hydrostatic Test Pressure Nominal Diameter
Test
Pressure
Leak-Tightness Test Pressure for fittings and for pipes not Centrifugally Cast
(mm)
(bar)
(bar)
80-300
50
25
350-600
40
16
700-800
32
10
900-1200
32
10
Tensile tests on the castings shall also be carried out at the works in accordance with BS 4772. The break faces of the test pieces shall show a regular, tight, light grey grain and shall not have any unfileable parts.
8.8.7 External Coating The external surface of pipes and the internal surface of sockets shall be protected against corrosion by a molten zinc spray coating (minimum deposit 130g/sq.m and a coating of bitumen complying with BS 4164 or a coating of bitumen complying with BS 4147 Type I Grade D or BS 3416 Type 2. The coating shall have a minimum thickness as specified in Table 9 of BS 534. Fittings shall have a bitumen coating only.
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Dipping, brush, spray or roller may be used to apply bituminous coatings. Surfaces to be coated shall be clean, dry and free from rust. Coatings shall dry rapidly with good adherence and not flake off and shall not flow when exposed to a temperature of 76 degrees centigrade. Where internal surfaces of pipes and fittings are coated, the coating shall not have any water soluble or toxic constituents or impart any colour, taste or smell to the water. In additional to the above coatings, all pipes and fittings shall be installed with a polyethylene sleeve, 200 microns thick minimum. The procedures for sleeving shall be as laid down by the pipe manufacturer and generally in accordance with ANSI A 21-5.
8.8.8 Internal Lining All pipes and fittings shall unless otherwise specified, be lined internally with sulphate resisting or high alumina cement mortar to the thicknesses given in the BS 4772. The materials used in the mortar shall comply with paragraph 33.3 of BS 534. Portland blast furnace cement complying with BS 146 may also be used. The mortar shall contain at least one part of cement to 3.5 parts of sand by mass. The cement, sand and water shall be thoroughly mixed to a standard consistency to provide a dense and homogeneous lining. Surfaces to be lined shall be free from all loose scale, dirt or foreign material detrimental to good contact between the metal and the lining. Pipes shall be spun lined or centrifugally spray lined with an applicator head. Fittings shall be centrifugally spray lined and finished to a comparable standard to that specified for straight pipes. The process of lining shall be controlled to produce a continuous layer of cement mortar over the bore of the pipe in a single pass. The inside of sockets and faces of flanges shall be free from cement mortar. The surface of the lining shall be substantially smooth, free from laitance, with minimal sand segregation and comply with paragraph 33.3 of BS 534. Isolated shrinkage cracks not exceeding 0.8mm wide shall be acceptable. Curing shall be carried out at not less than 4 degree C and in such a manner as to produce a properly hydrated, hard and durable cement mortar lining. Subject to the S.O.'s prior approval, curing may be effected by application of bitumen coating complying with BS 3416 Type 2 while the lining is still moist. Small areas of damaged linings may be repaired by cutting back the lining to the metal surface, thoroughly wetting the exposed surfaces of metal and lining, and patching with fresh stiff cement mortar worked in thoroughly to ensure a good bond with the exposed surfaces.
8.8.9 Fittings Standard fittings without branches shall be Class K12 and those with branches shall be Class K14. They shall be flanged or socket ended and generally conform to the dimensions given in the respective tables of BS 4772. The Contractor shall submit drawings showing all details and dimensions of the fittings offered.
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8.8.10 Joints The Contractor shall submit drawings showing all details, dimensions and the maximum joint deflections of the "push-in" and "mechanical" type deflection joints. All flexible joints shall be supplied complete with bolts, nuts, glands, washers, rubber gaskets, locking rings and other accessories. The gasket shall be of elastomeric material complying with BS 2494 and compatible with the fluid to be conveyed in the main. It shall provide a positive seal within the manufacturer's range of maximum joint deflection and withdrawal, and in the range of pressures likely to occur in the pipeline including those below atmospheric pressure where applicable. The Contractor shall state the material, type and quality of the rubber gaskets offered. (a)
Flanged joints (Only for Force Mains)
Flanges shall have a nominal pressure rating of 16 bars. They shall be integrally cast on square to, and concentric with, the longitudinal axis of the pipe or fitting. They shall be of the raised face type and truly faced over their whole width, but may also be supplied as cast where particularly accurate moulding processes are used subject to the approval of the S.O. The finish on flange joint surfaces shall be in accordance with Clause 4.4 of BS 4504. Bolt holes shall be drilled off centre lines, concentric and truly in line end to end with the longitudinal axis. However, where particularly accurate machine moulding processes are used that produce equivalent functional quality, bolt holes may be cored. Flange and neck thickness shall comply with Table 11 of BS 4772 while diameters of flange raised face and drilling shall comply with Table 16/3 of BS 4504. Each set of flange jointing materials shall be supplied complete with nuts, bolts, washers and joint gaskets. Joint gaskets shall be of the flat section 4.5 mm thick medium rubber to BS 1154 Class Y3 reinforced with two-ply fabric in accordance with BS 5292, and shall not extend beyond the bolt pitch circle. Each bolt shall be supplied with a nut and two washers and shall be of sufficient length to show two threads past the nut when installed. Bolts and nuts shall be of mild steel with galvanized surfaces, hexagonal and in accordance with BS 4190 unless otherwise specified. Bolts, nuts, ragbolts and spring washers shall be stainless steel for joints in wet wells, other locations where the joint is within the splash zone or subject to submergence in liquid or otherwise exposed to a corrosive atmosphere. Stainless steel nuts, screws, washers and bolts shall be manufactured from Grade 316 S31 steel complying with BS 970: Part 1 or BS 1449 : Part 2. Where bolting is incompatible with the material being fixed, suitable isolating washers and sleeves shall be used. Flanges shall be properly aligned before any bolts are tightened. (b)
Mechanical flexible couplings and adaptors (Only for Force Mains)
Joints using mechanical flexible couplings and adapters shall be made in strict accordance with the instructions given by the manufacturer.
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After the pipe ends have been examined, prepared and painted as specified in the Specification, the flanged portions of the flexible coupling shall be placed over the ends and rotated to check circularity, following which the rubber rings shall be placed into position at 25 mm or so back from their final location. The central sleeve, with the taper plug gauge screwed into position, shall then be placed over the end of the fixed pipe, and the end of the free pipe entered into it and pushed home so that the plug gauge shall set the pipe ends the correct distance apart. At this stage it should be possible to rotate the central sleeve freely. The rubber rings shall then be eased forward into position without disturbing the setting of the central sleeve, the flanges brought into position, and the bolts inserted and tightened, working in sequence around the joint. The plug gauge should be slackened and removed before the securing bolts and nuts are fully tightened. These bolts and nuts shall be tightened in regular sequence starting on opposite side of the bolt circle and going around at least twice to ensure that they are all tight so that an even tension all rounds the joint is obtained. Internal protection to the joint is to be effected by pouring hot bitumen into the annular space between the pipe ends against an inflated mandrel. The mandrel shall be coated with lime wash before inserting into the joint and then inflated to the appropriate pressure (about 13.8 kPa). The two screwed plugs shall be removed from the sleeve and a funnel and vent shall be screwed in. Bitumen shall be heated up to 250 degrees Celsius and poured into the funnel until the annular space between the pipe ends is filled. After the joint has cooled and set, the funnel, vent and mandrel shall be removed and the plugs replaced and tightened. The external protection of the pipe is to be effected by enclosing the joints with run bitumen compound, in accordance with the manufacturer's instructions. Before casing, the ends of the pipes are to be coated with a suitable preparation to ensure adhesion of the covering.
8.8.11 Marking In addition to the requirements of Clause 8.1.2 ductile iron pipes shall be marked with two-socket penetration lines on the spigot end for use with a "push-in" flexible joint.
8.9
Steel Pipes
8.9.1 General Steel pipe shall only be used for pressure pipe. Steel pipes, fittings and specials shall be made from mild steel by the longitudinal electric fusion welded process or the spiral seam welded process. Pipes and specials shall be protected internally with High Alumina or Sulphate Resisting cement mortar lining and externally either by reinforced coal tar enamel or bitumen coating or with two coats of red lead oxide paint as approved by the S.O. Pipes and specials shall be supplied either flanged, or with plain ends truly circular for collar welded joint or mechanical couplings. All pipes and specials shall be suitable for the maximum working pressure to which the pipe or special will be exposed with due allowance for the effects of surge etc. The ends of all pipes and specials shall be suitably covered and protected against damage during transit to the Site by Hessian wrapping or other superior means of protection. All flanges shall have wooden discs temporarily bolted on. None of the packing or protection shall be returnable. The design and manufacture of the pipes and specials shall be in accordance with the requirements of BS 10:1962, BS 534:1990, BS 3601:1987. The steel used shall be made by the open-hearth process or other approved process, and shall have a minimum tensile strength of 400 mega Pascal.
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8.9.2 Testing Samples of the steel plate supplied for the manufacture of pipes and specials, and test pieces cut from the pipes themselves shall be tested in accordance with BS 534:1990 and BS 3601:1981. The Manufacturer shall submit certificates in duplicate from the steel manufacturer stating the results of the tests specified on samples and test pieces, and also the steel used, the process of manufacture and chemical analysis. Before lining and coating, all pipes and specials shall be tested hydraulically at the factory as specified in Clause 14.4 of BS 3601: 1987 at a pressure not less than twice the maximum working pressure.
8.9.3 Dimensions The pipe diameters given refer to the outside diameters (O.D.) of uncoated pipes in accordance with BS 534:1990. Flanges are specified by flange size designation (Nominal bore of pipe) in accordance with Table 10/5 of BS 3601.
8.9.4 Straight Pipes Straight pipes shall be supplied in standard lengths of 9 metres as defined in the relevant British Standards. The variation in length from the nominal standard length shall be kept as small as possible within the normal methods of manufacture. Straight pipes shall be supplied in half lengths and quarter standard lengths as required. These pipes will be required for cutting to exact lengths during laying to form closing lengths.
8.9.5 Specials Specials conform generally to the appropriate dimensions given in BS 534:1990 and BS 4504:1990 unless otherwise stated. Where it will not be practicable to carry out the factory hydraulic test on the completed specials, the specials may be fabricated by welding together sections out from straight pipes which have been satisfactorily tested, lined and sheathed. In all respects, the specials shall be fabricated and tested in accordance with Clause 20 of BS 534:1990. The lining and coating shall be repaired by hand after welding and testing.
8.9.6 Joints (a)
Collar joints
Collars shall be truly circular, and shall conform to Clause 25 of BS 534:1990. They shall be at least equal in thickness and quality to the adjoining pipes. (b)
Mechanical couplings
Mechanical couplings shall be of approved type. Each coupling and adaptor shall be capable of withstanding twice the working pressure. Couplings shall be without the centre register and shall be supplied with three removable locating plugs fitting into holes drilled and tapped on the centre line of the sleeve. Couplings and adaptors shall be supplied complete with all necessary couplings rings, nuts, bolts, washers and rubber rings. Couplings connecting pipes of different outside diameters shall be stepped and suitable for the particular purpose required.
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(c)
Flanged joints
Flanges shall be of steel and welded to the pipe by the metal-arc process or other approved method. Flanges shall be truly faced over their whole width and the bolt holes drilled off centre and truly in line end to end with the longitudinal axis. Flanges shall be in accordance with table 10/5 of BS 4504:1989. (d)
Welded joints
Where jointing of steel pipes and specials by welding is approved by the S.O. it shall be by means of an external circumferential electric arc weld at each joint. The weld shall be of the convex full fillet type, the length of each leg being not less than the thickness of the metal of the pipe. The weld shall be made manually by the metalled arc process using approved types of electrodes, and shall be carried out in two stages, one root pass followed by one or more weave cover passes. Each time the arc is started it shall be manipulated to obtain complete fusion of the weld metal with the pipe metal and any previously deposited weld metal. All slag shall be completely removed and the weld metal and the adjacent pipe metal shall be cleaned by wire brushing. All welds shall be subject to visual inspection by the S.O. and shall comply with the requirements of BS 5950 : Part 1 : 2000, BS EN 1011 and BS 4872 for freedom from undercutting, fusion penetration and soundness. (i)
Welding procedure
All electric arc welding equipment shall comply with BS 638. The Contractor shall submit details of the welding procedure which he proposes to adopt for the S.O.'s approval. Details shall include: (I) (II) (III)
Make, type and gauge of electrodes Size, shape and number of runs in welded joint. Current strength
The Contractor shall demonstrate his chosen welding technique on a pipe and joint of the same metal and thickness as the pipeline to be welded. Bare steel shells and joints shall be supplied by the Contractor free of charge for this purpose. Test specimens shall be prepared and tested in accordance with BS 2633. Only procedures approved in writing by the S.O. shall be adopted in welding on the pipelines, and change from one procedure to another will not normally be permitted without submitting the new procedure for re-testing. (ii)
Welding personnel
Only competent and certified welders shall be employed on the Works, and every welder before commencing any joint welding shall prepare specimens for testing in accordance with BS 2633 for each welding procedure proposed by the Contractor. The Contractor shall make test specimens which shall be tested in the presence of the S.O. for each welding procedure proposed. The S.O. will advise the Contractor in writing which welders the S.O. considers produce satisfactory test specimens. Only these welders will be allowed to joint pipes in position and
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the S.O. shall be at the liberty to withdraw his approval to any welder responsible for making joints which fail to meet the required standard. The Contractor shall supply all materials and labour for preparing the test specimens and shall allow for their cost and for laboratory test charges in the unit rates for welding. (iii)
Radiographic examination of welded joints
Welded joints for large diameter pipes of 1200 mm diameter and above shall be radiographed at random as directed by the S.O. At least 2 strips each for internal and external welds shall be sampled for quality check for a slip joint. The contractor shall make all the necessary arrangement apparatus and equipment and a specialist to carry out the test. The analytical report in duplicate shall be submitted to the S.O. three days after the test. If the weld does not meet the requirements of the Specification, the weld will have to be gouged out and made good. The repaired welds shall be radiographed again at no extra cost to the Employer. The frequency of radiographic examination for welded joints shall be one in every fifty. (iv)
Completion of coating of welded joints
After each length of pipeline has been laid the external coating shall be made good. Bare metal shall be thoroughly cleaned to a bright metallic finish and it shall be immediately coated with a primer solution. The primer shall be applied cold by brush. As soon as the primer has set, the coating shall be completed by running hot coal tar enamel or bitumen, whichever is compatible with the external coating, into an aluminium mould placed over the joint and overlapping the coating by 75mm.
8.9.7 Protection Before internal lining and external protection, all pipes and specials shall be cleaned to remove all scale rust, oil, grease or other foreign matter, by an approved method in accordance with Clause 28 of B.S. 534: 1990. A priming coat shall be applied immediately if cleaning is done by sand or shot blasting.
8.9.8 Lining The internal lining of all plain-ended pipes and specials shall be extended to the ends and finished square with the ends. All steel pipes and specials shall be protected internally with cement mortar lining using sulphate resisting or high alumina cement in accordance with Clause 33 of BS 534:1990.
8.9.9 Coating Steel pipes and specials shall be protected against external corrosion by coating and wrapping in a neat and workmanlike manner. All coating and wrapping shall be able to withstand the attack of soil and ground water with sulphate content as high as 0.34% and a pH as low as 3.1. Within 15 minutes of each pipe or special being cleaned to base metal, a uniform thin coat or primer compatible with the coating material to be used shall be cold applied by flood coating, spraying or brushing. The primer shall be allowed to dry properly before the coating material is applied but if more than 96 hours elapses before coating or if the primer becomes dead, powdery or crumbly it shall be cleaned off and the pipe or special shall be reprimed. The coating material shall conform with the requirements of either sub-clauses (a) or (b) hereinafter specified.
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(a)
Bitumen coating: The pipes and specials shall be coated with appropriate layers of bitumen containing a mineral filler complying with Type 2 of BS EN 10300. The coating shall be applied hot to have a total thickness of 6.5 mm and shall be reinforced with an inner wrap and an outer wrap.
(b)
Coal tar enamel coating: The pipes and specials shall be coated with appropriate layers of plasticised coal tar pitch base enamel complying with Clause 30.6 of BS 534:1990. The coating shall be applied hot to have a total thickness of 6.5 mm and shall be reinforced with an inner wrap and an outer wrap.
The wrapping materials shall be spirally wound onto the pipes and specials simultaneously with the coating material. Each wrap shall be from 300 - 450 mm wide and the edges shall overlap by 15mm to 25 mm. Care shall be taken to ensure that the inner wrap does not come in contact with the pipe metal or with the outer wrap. Inner wrap: The inner wrap shall be a glass fibre resin bonded tissue reinforced in the longitudinal direction with parallel glass threads spaced 10 mm apart. The nominal thickness shall be 0.5 mm and the minimum weight shall be 46 gms per sq. metre. Outer wrap: The outer wrap shall be a glass fibre resin bonded tissue reinforced in the longitudinal direction with parallel glass threads spaced 10 mm to 25 mm apart. It shall be impregnated with a material fully compatible with the coating material to give a finished thickness of 0.75 mm. All coated pipes and specials shall be inspected for defects. Thickness shall be determined by a pit gauge, continuity with a holiday detector and coating quality by cutting out 75 mm x 75 mm samples. The whole coated surface area of all pipes and specials shall be tested for pinholes or other invisible defects in the coating using an approved holiday detector at a potential of 14,000 volts. Any lengths on which the coating is poorly applied shall be cleaned to bare metal and re-coated. Touching up can be used to repair minor defects. All repairs shall be checked for thickness and continuity.
8.9.10 Painting All pipes, specials, couplings etc. to be laid above ground shall be painted with two coats of red lead oxide paint.
8.9.11 Marking and Transportation In addition to the requirements of clause 8.1.2 for steel pipes, sized pipes shall be marked with two longitudinal parallel bands throughout their whole length.
8.9.12 Repair of Lining and Coating Only specially competent and skilled men shall be employed to carry out repair work to damaged linings and coating. Small cracks and flaws in the internal concrete lining of steel pipes and specials may, with the prior approval of the S.O. and if they are accessible, be repaired on Site. Such cracks may be repaired by cutting out a 10 mm x 10 mm dovetailed key and making good with a semi-dry mortar (proportion 1
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part cement to 2 parts coarse sand) well tamped into the groove, and cured by keeping it damp for 7 days. Alternatively, small cracks may be caulked with an epoxy resin filler. The external coating of steel pipes and specials shall be made good wherever the steel has been exposed or the thickness of the coating does not adhere tightly to the steel. Where the steel has been exposed all rust and dirt shall be removed carefully by wire brushing or otherwise, and when perfectly clean and dry, a coat of special quick drying priming paint applied before re-fettling. Small stones which may have become embedded in the coating shall be picked out and the coating refettled by heating locally with a blow lamp and smoothing over with a fettling knife. Additional external jointing material shall be added wherever necessary. The compound used for repairing coatings shall be compatible with the coating material and shall be approved by the S.O. All defects to linings and coating shall be made good to the entire satisfaction of the S.O.
8.10 General for Pipeline Installation 8.10.1 Scope of Works The Contractor shall be responsible for the installation of pipelines for sewers and force main as delineated in this specification, and for providing all materials, labour and equipment necessary for the installation of those works.
8.10.2 Definitions The following terms shall have the meanings hereby assigned to them except where the contract clearly renders these meanings inapplicable: “Pipe”
:
means pipes or pipes, bends, junctions and other specials and fittings and includes joints and jointing parts.
“Installation”
:
means supplying, hauling, handling, placing, fixing. jointing in position, and testing whether in trench or elsewhere in the Works.
“Pipeline”
:
means those parts of the Works comprising pipe, manholes, and fittings.
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8.10.3 Dimensions of Pipes The Contractor shall submit to the S.O. all technical information, the internal, external and other necessary dimensions of the pipes prior to the purchase and supply of the pipe to the work site.
8.10.4 Specialists, Inspection and Testing The Employer may, at his cost, employ the services of a specialist firm to assist the S.O. as he may require in any matter connected with pipe, manholes, and fittings including the inspection of materials and workmanship and the witnessing of tests at any stage (including manufacture) during the execution and maintenance of the works. Such independent tests may be carried out at any stage during the execution and maintenance of the Works, but they shall not relieve the Contractor of any of his own obligations under the Contract. To the extent ordered by the S.O., the Contractor shall provide labour, plant and materials (but not special testing equipment) for direct assistance to the specialist firm in their inspection and independent testing and for any further work of investigation and repair which the S.O. considers necessary as a result of such inspection or testing. The cost of providing labour, plant and materials as aforesaid shall be borne by the Contractor where in the S.O.’s opinion the inspection test or further investigation shows that materials and workmanship provided by the Contractor do not comply with the specified requirements, but otherwise shall be borne by the Employer.
8.10.5 Tools for Pipe Installation The Contractor shall supply all necessary tools for cutting, chamfering, jointing, testing and for any other requirement for satisfactorily installing the pipelines.
8.10.6 Handling, Storage and Protection during Transit During storage, handling, and transporting, every precaution shall be taken to prevent damage to the pipe and fittings. Pipe shall be handled by means of approved hooks on ends of sections, by means of fabric slings, or other methods strictly in accordance to the manufacturer’s recommendation for the type of pipe used and as approved by the S.O. Dropping or bumping of pipe will not be permitted. Damaged pipe shall be replaced or repaired by the Contractor at his expense and such repairs shall be to the approval by the S.O. Pipes shall not be dragged over the ground and, if rolled shall be rolled only over adequate timber bearers to prevent damage. Pipes may be stored in the open, but shall be placed on adequate timber bearers to prevent damage to sheating or sockets. Pipes may be stacked one above the other up to the height as recommended by the manufacturer subject however to the approval of the S.O, provided suitable protective packing is placed between them. If any pipes or fittings shows signs of corrosion or deterioration during storage they shall immediately be treated at no extra charge by the Contractor as the S.O. directs to arrest and prevent the corrosion. Coated pipes shall be lifted and moved only by wide non-abrasive slings or other means acceptable to the S.O. Wire ropes, chains and hooks shall not be permitted to come into contact with the coating. Coated pipes shall not be rolled or dragged along the ground. Coated pipes shall be stacked in one layer only at pipe storage yards approved by the S.O. or strung along the pipeline route and in such manner that the coating is not damaged. The Contractor shall supply adequate packing between pipes for this purpose. Coated pipes shall be kept clear of the ground and rested on padded sleepers or supports.
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Care shall be taken with elastomer joint rings or gaskets and washers to ensure that they are kept in weatherproof storage away from direct sunlight. They shall not be stored at low temperature to prevent them from becoming rigid and losing their flexibility. The ends of all pipes and fittings shall be suitably protected against damage during transit with straw contained in hessian secured to the pipe ends. All flanges shall have wooden discs temporarily bolted on. Pipes and fittings shall be wrapped or cushioned so that no load is taken directly on the external coating. The Contractor shall be responsible for the disposal of all materials used for the protection of pipes and fittings during transit.
8.10.7 Inspection at Time of Installation Pipes and fittings including any sheathing, lining or protective paintwork, shall be inspected by the Contractor immediately before and after installation and any damage shall be repaired by the Contractor as directed by the S.O. before the pipe or fitting is installed or jointed as the case may be. Any specified material required for the repair of pipe, sheathing or lining shall be obtained by the Contractor at his cost from the pipe supplier and shall be used with due regard to his recommendation. The S.O. may himself, and without thereby relieving the Contractor of any of his obligations, inspect and test the pipe and appurtenances by any means he considers appropriate and the Contractor as aforesaid shall repair any damage discovered by such inspection. The Contractor shall remove from the Site any pipe or appurtenance which in the opinion of the S.O. is so badly damaged as to be unfit for incorporation in the Works.
8.10.8 Laying Diagrams The Contractor shall submit for approval detailed laying diagram showing the following : a.
Location, length, design and designation by number of each pipe section and pipe special to be furnished and installed.
b. c.
Station and elevation of pipe invert at all changes in grade. All data on curves and bends for both the horizontal and vertical alignment.
All applicable provisions of these Specifications shall apply to the preparation and submittal of said drawings, and their subsequent approval and possible revision. In the event that the final ‘As-Built’ condition varies from the original approved shop drawings, the Contractor shall revise the shop drawings and laying diagrams to the ‘As-Built’ condition.
8.11 Installation of Pipes Installation of pipes shall include both gravity sewers and force mains. Trench excavation shall be carried out strictly in accordance to Section 2 of this Specification, Clauses 2.13 to 2.37 inclusive.
8.11.1 General Installation Work Unless specified otherwise, pipe shall be installed singly and shall not be jointed until after they have been installed. Except where otherwise shown in the drawings, all sewer and force main pipes shall have flexible joints.
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In the case of force main all above ground crossings, section of all fittings and bends, the joints shall be all flanged joints. The line and levels of the pipelines are shown approximately on the drawings. The contractor shall provide evidence to show that benchmarks used for control of line and level are cross-referred with permanent benchmarks established by Jabatan Ukur Malaysia. The pipe shall be accurately installed to the lines, levels, grades and positions set out by the Contractor from data given on the drawings or supplied to him by the S.O. Pipe and specials that are required to be fixed onto or built into other structures shall be positioned as shown on the drawings or as directed by the S.O. Brackets, steelwork cradles and the like fixings shall be in accordance with typical details shown on the drawings, or if not so detailed shall be as approved by the S.O. Pipe shall rest on a solid and even foundation or bedding for the full length of the pipe barrel. Suitable additional excavation shall be made to accommodate sockets or collars. Except where directed or shown otherwise, the minimum cover to the laid pipes, measured at the highest point at the joint, shall be 1.2m in roadways and 0.75m in open fields. The Contractor shall keep the interior of pipes clean and free from water, dirt, stones or other foreign matter as installation proceeds. At the end of the day’s work or whenever the work ceases for any reason, or at other times when installation work is not proceeding, the unfinished/open ends of pipes shall be securely closed or sealed off by wooden plug or a tight fitting plug or other approved stopper. The pipe trench shall be kept free from water at all times. The Contractor shall take all necessary precautions to prevent the pipe from floating due to water entering the trench from any source, and shall assume full responsibility for any damage due to this cause. The Contractor shall restore and replace the pipe to its specified condition and grade if it is displaced due to float at ion. All pipelines adjoining concrete structures (including manholes) shall have a mechanical (flexible) joint within or 600mm length (for pipe up to 300mm diameters) or 900mm length (for pipes greater than 300mm diameter) of the outside face of such structures. The Contractor shall, after excavating the trench and preparing the proper bedding for the pipe, furnish all necessary facilities for properly lowering and placing sections of the pipe in the trench without damage and shall properly install the pipe. The section of pipe shall be fitted together correctly and shall be laid true to line and grade in accordance with the bench marks established by the Contractor.
8.11.2 Pipe Laying Each pipe shall be carefully lowered onto its prepared bed by means of necessary slings and tackle. A recess shall be left in the prepared bed to permit the sling to be withdrawn. If the prepared bed is damaged the pipe shall be raised and the bed made good before pipe laying is continued. Pipe shall be laid upgrade unless otherwise authorized by the S.O. In general socket and spigot pipes shall be laid with socket ends upstream. No pipe shall be rolled into place prior to lowering into the trench except over suitable timber planking free from roughness likely to damage any coatings. Before laying, each pipe shall be cleaned out and inspected for defects. Before any pipe is lowered into place, the bedding shall be prepared so that each length of pipe shall have a firm and uniform bearing over the entire length of the barrel. The pipes shall be laid in straight lines, both in the horizontal and vertical planes, between manholes or, where directed in the case of force mains and larger diameter sewers to regular curves.
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Each pipe shall be plumbed to its correct line and directed and accurately sighted by means of boning rods and sight rails fixed to secure posts which shall be set up and maintained at each end of the sewer to be laid and not more than 70 m apart. Sight rails shall be clearly painted in contrasting colors and be not less than 150mm deep, straight and level. Boning rods shall be of robust construction clearly painted and accurately made to the various lengths required, the lower end being provided with a shoe of sufficient projection to rest on the invert of the pipes as laid. The boning rod shall be complete with a vertical spirit level. Boning rods and sight rails shall not be removed until the pipeline has been checked and approved by the S.O. Any pipe which is not true alignment, both vertical and horizontal, or shows any undue settlement after laying, shall be taken up and relaid correctly by the Contractor at his own expense, when so ordered by the S.O. No pipe shall be laid which is damaged, cracked, checked, or spalled or has any other defect deemed by the S.O. to make it unacceptable, and all such sections shall be permanently removed from the work. Where sub-soil water is encountered it shall be kept below the sockets when jointing by pumping or other means. In no case shall pipes be jointed before being lowered into position. If any damage should occur to any pipes through failure of the Contractor to comply with these conditions, the damage shall be made good at the Contractor’s expense. Pipe sections shall be joined in such a manner that the offset of the inside of the pipe at any joint will be held to a minimum at the invert. The maximum offset at the invert of pipe shall be 1 % of the inside diameter of the pipe or 9.4mm whichever is smaller. Unavoidable offsets shall be distributed around the circumference of the pipe in such a manner that the minimum offsets occurs at the invert. After the joints have been made, the pipe shall not be disturbed in any manner. The interior of each pipe, after being laid, shall be thoroughly cleaned. Pipe will be carefully inspected in the field before and after laying. If any cause for rejection is discovered in a pipe after it has been laid, it shall be subjected to rejection. Any corrective work shall be approved by the S.O. and shall be at no cost of the Employer.
8.11.3 Closures and Short Sections For the purpose of reducing the angular deflections at pipe joints, and for closure sections, the Contractor shall be permitted to install pipe sections of less than standard length. Closing courses and short sections of pipe shall be fabricated in accordance with approve cutting procedure and installed by the Contractor as found necessary in the field. Where closing pieces are required, the Contractor shall make all necessary measurements and shall be responsible for the correctness thereof.
8.11.4 Pipe Bedding for Sewer Pipes The surface shall be firm and true to grade. If soft, spongy, unstable, or similar other material is encountered upon which the bedding material or pipe is to be placed, this unsuitable material shall be removed to a depth ordered by the S.O. and replaced with suitable densified crushed rock bedding material.
Bedding shall be in accordance with details on the drawings. Except where concrete or one of the following materials is specified, bedding material supporting the pipe or conduit shall be gravel,
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disintegrated granite, crushed aggregate, native granular material, or other material approved by the S.O. Limestone shall not be used. After trimming, granular bedding material shall be spread in the trench bottom and screeded with a template. The Contractor’s rates shall include for provision of suitable material for granular bedding, and also for removal and disposal of excess material arising from the trench excavations, due to the granular bedding. Material for granular bedding shall meet the following requirements: Table 8.8 : Percentage Passing BS Sieve Size 19mm 9.5 mm 4.75 mm 2.36 mm
Min. 100 80 10 0
Max. 90 25 15
The material shall be tested in accordance with B.S. 812, Section 8 when required by the S.O. and shall have a 10% fines value greater than 50 kN. Material retained on a 7 mm sieve shall have an index of flakiness less than 25% and an index of elongation less than 45%. Whenever the S.O. directs the following test for compaction shall be carried out on the material for granular bedding in accordance with British Standards CP 312. If through the Contractor’s neglect any trench bottom is excavated below the grade shown on the plans, it shall be refilled to grade of pipe invert with bedding material, properly compacted into place at the Contractor’s expense.
8.11.5 Concrete Protection of Sewer Pipes Where sewers are to be laid on concrete bedding or surrounded in concrete, the pipes shall be temporarily supported on precast concrete bedding blocks positioned at each end of each pipe, clear of the sleeve joints. The width of the bedding block shall be half the diameter of the supported pipe subject to a minimum of 115mm. The blocks shall be left in and paid for as concrete bedding. The blocks shall be set to level allowing for the thickness of the pipe wall, and sight strings shall be used to check alignment. The greatest care shall be taken to avoid movement of the pipe and to ensure a continuous support during concreting. Should any pipe become either partially or wholly clogged before final acceptance of the work, it shall be cleaned out or replaced by the contractor at no extra cost to the Employer. All sewers with less than 1.2 metre of cover under roads, or 0.75 metre where not under roads, shall be surrounded with at least 150mm of concrete Grade 20. The depth of cover shall be measured from original ground level to the top of the barrel of the pipe. To ensure flexibility of the sewers concrete protection shall be interrupted over its full cross-section at each pipe joint by a 12 mm thick board of softwood, or other approved material cut to shape.
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8.11.6 Protection of Joints for Force Mains After the pipelines have been tested and found satisfactory, the protection of joints shall be completed. a.
Flanged Joints shall be reprimed and painted with aluminium (if above ground) and two coats of heavy bodied black bituminous paint for joints below ground.
b.
For Welded Joints, the exposed surfaces shall be cleaned by sand blasting or through wire brushing, primed by tar primes and spiral wrapped with coal tar and coal tar saturated with asbestos felt so that a continuous sheathing free from detect is formed and given a coat of white wash.
c.
Mechanical Joints (K-Type Joints) shall have similar protection as the Flanged Joints.
The Contractor shall furnish and install complete all the necessary temporary bulkheads or steel boiler heads and appurtenances thereto in the pipeline used for backfilling purpose and shall remove such bulkheads upon completion of the line.
8.11.7 Tolerances of Alignment and Invert Levels The accuracy of line direction grade and invert levels shall not deviate more than + 50mm for every 100m (or 1/2000) of pipe installed between 2 manholes.
8.12 Special Laying Methods: Jacking The jacking method of pipelaying shall be employed where indicated on the Drawings or as directed by the S.O. Unless otherwise specified or as shown on the Drawings the method and equipment to be used for this purpose shall be proposed by the Contractor but a detailed description of his proposal as well as the safety measures which he will be taking shall be submitted to the S.O. for prior approval before commencement of pipejacking works. Approval of the Contractor’s proposal by the S.O. shall not relieve the Contractor of the responsibility for making a satisfactory installation which meets the technical criteria set forth hereunder. One single approved manufacturer shall supply pipes and pipe joints used in pipe installation by jacking method.
8.12.1 Pipe Jacking - Procedures Where a steel shield is utilized during the jacking operation, this steel shield shall be bolted to or by other approved means joined to the first piece which is being jacked. The Contractor shall be required to use a jacking ring. The jacking ring may be either steel or concrete construction and shall be used at all times when pipe is being jacked. This jacking ring will allow the jacking pressure to be distributed evenly around the wall of the pipe. The Contractor shall also be required to use a jacking frame during all operations. The jacking frame shall be designed to distribute the stresses from the jacks evenly to the jacking ring.
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After the jacking operation has begun, the Contractor shall work continuously (24 hours per day) until the complete length of jack pipe is installed. The pipes shall be jacked into place true to line and level. The maximum tolerance allowable in the displacement of the centreline of the laid pipe from the design centreline is 50mm in the horizontal plane and 25mm in the vertical plane but there shall be no back fall at any point. Any pipe that is not laid in its correct position must be removed and re-laid or adjusted to obtain its correct position. There shall be provision to prevent the relative movement between pipes at the joints by the use of steel gaiters or other approved methods during jacking operation. A packing piece of compressible material shall be provided at each joint and shall be securely held before the pipes are lowered into the thrust pit. Details of proposals shall be submitted to the S.O. for approval. The Contractor shall be required to furnish, install and remove to the extent required thrust blocks or whatever provisions that may be required for backing up the jacks employed in driving the pipe forward. The jacking pit shall also be equipped with steel rails or beams embedded in concrete. These rails or beams will be used for placement and alignment of each pipe during the jacking operation. The Contractor shall be fully responsible for the design and construction of jacking and receiving pits, thrusting wall, installation of jacking equipment, sheeting, bracing etc. and for the efficient execution of the jacking operation. Full details of his proposals, including plant, shield machine equipment, operating procedures, jacking pit and intermediate jacking stations shall be submitted to the S.O. and shall be fully satisfactory to him before construction. However, review of the plans shall not relieve the Contractor from his responsibility to provide a safe and satisfactory jacking pit. The Contractor shall be required to monitor closely the progress of the jacking operation. Daily site records of thrusting pressures and the line and level measurements shall be properly maintained and shall be available to the S.O. at all times. It is the responsibility of the Contractor to ensure that the completed pipes are watertight. Pipe testing shall be carried out strictly in accordance to the requirements of Clause 8.17. If leakage is detected at any time before the end of the Maintenance Period, the Contractor shall carry out any remedial work as necessary to make the works watertight all at his own expense.
8.12.2 Alternative Trenchless Pipe Installation Methods The contractor shall take into full consideration all geological conditions in which the proposed pipe jacking will be carried out and shall modify the methods of pipe installation as appropriate subject to the approval of the S.O. Alternative methods of trenchless pipe installation such as micro tunnelling or rock boring methods may need to be used. The contractor shall satisfy himself with respect to the suitability of the machines he propose to use for the purposes of installing the pipe in the ground conditions expected to be encountered.
8.12.3 Type of Pipe Used for Jacking All pipes used shall fulfil the Specifications set out in this Contract. Pipes used for jacking shall be mild steel, reinforced concrete or vitrified clay pipes and it shall be the responsibility of the Contractor to ensure that the pipes used are able to withstand the laterally induced jacking stresses without damage. The Contractor shall submit calculations showing that the structural strength of the pipes meet requirement for the entire jacking operations. Shop drawings of all pipes shall be submitted for evaluation before the commencement of pipe manufacture.
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Unless otherwise specified or directed by the S.O., the types of joints permitted for jacked pipelines are butt joints and spigot and socket joints, but where a butt joint is used the butting surfaces should be modified to accommodate the rubber ring or similar sealing device to make the joint watertight. Any leakage detected shall be resealed to the satisfaction of the S.O. The concrete pipe used shall be adequately protected against corrosion from sewage with high alumina or sulphate resisting cement lining as specified. The pipes shall also satisfy the cracking strength requirements. Where pipe jacking is carried out using a larger concrete pipe as a sleeve and vitrified clay pipes are inserted through the sleeve, all details including pipes, joints, sandfilling and grouting shall be as shown on the drawings and as approved by the S.O.
8.12.4 Alignment Control and Tolerances In order to maintain a high level of accuracy of line and grade, extreme care shall be exercised by the contractor when setting out the guide rails for the pipe and during actual jacking operations. The jacking frame if used must be aligned perpendicularly to the direction of pipe travel. During the course of jacking, the Contractor shall carry out regular checks to ensure that the pipe adheres to the pre-determined alignment and he shall make modifications to the jacking procedure to correct any deviation detected. Accuracy of line direction and grade shall be kept at +50mm from the designed alignment for every 100 metres of pipe installed but up to a maximum deviation of 100mm.
8.12.5 Joints for Jacking Pipes Pipes to be used in jacking shall have joints which are manufactured to close tolerances of within +2mm of manufacturer’s specified dimensions. The types of joints to be employed shall be approved by the S.O. prior to supply of pipes to the site. Stainless steel 304 collars shall be used and shall be manufactured to tolerances of +2mm. The joints shall be flexible and watertight. The Contractor shall be responsible for the proper functioning of the joints. Spigot and socket shall be used to join pipes using pipe-sleeve jacking method. This method normally used when the smaller pipe is non-jacking pipe. The smaller pipe shall be pushed along the invert inside the bigger pipe sleeve progressively. The void space inside the pipe sleeve shall be filled with sand or cement grout to keep the inner pipe in position. This method of jacking is not commonly used nowadays since the jacking pipes are also manufactured in small diameters for different types of pipes.
8.12.6 Joints Performance Test All joints of pipes installed by jacking shall be subjected to and pass the Leakage Test as described under Clause 25.8 (Tests for flexible joints) of BS 5911 (Part 1): 2002.
8.12.7 Jacking and Receiving Pits The Contractor shall submit details of his proposed jacking pit and receiving pit to the S.O. for prior approval before commencement of jacking works. All material excavated during the construction of the jacking and receiving pits shall be removed from the Site. Only approved backfill material shall be permitted to be used for backfilling such excavations upon completion of jacking works.
8.12.8 Jacking Records
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The Contractor shall maintain accurate and complete jacking records which shall be submitted to the S.O. after completion of each jacked sections.
8.13 Changes In Line and Grade In event obstructions not shown on the plans are encountered during the progress of the work which will require alterations to the drawings, the S.O. shall have the authority to amend the drawings and order the necessary deviation from the line or grade shown. Contractor shall not make any deviation from the specified line or grade without approval of the S.O.
8.13.1 Deflection at Certain Joints Where the S.O. orders or allows a change of direction to deflect force mains from a straight line, either in the vertical or horizontal planes to avoid obstruction or where long radius curves are permitted, the amount of deflection allowed shall not exceed that required for satisfactory connection of the joint and shall be approved by the S.O. Where a change of direction cannot be made by deflection at the joints of ordinary straight pipes, bends shall be used. The locations of such bends and other specials are indicated upon the drawings and their exact positions will be determined by the S.O. on the Site.
8.14 Stream and River Crossing Work at any crossing of a watercourse shall be carried out as expeditiously as possible to the satisfaction of the S.O. and any responsible Authority with the minimum interference to the free flow of the water in the watercourse. Details of any temporary works which may effect the flow of the watercourse shall be submitted to the S.O. at least 14 days before starting work. Where the pipeline passes underneath a river, stream or ditch it shall be cased in concrete unless otherwise approved by the S.O. The minimum thickness shall be 150mm. Unless otherwise shown, the depth of cover shall not less than 600mm from the bed of the river, stream or ditch to the top of the concrete. The Contractor shall fill the trench in both banks with rockfill or concrete up to levels as shown on the drawings or as directed by the S.O. The extent of this work may be varied to suit each individual crossing. Unless otherwise ordered, the concrete encasement of the pipe shall extend at least to a section vertically below the tops of the banks. Protection against erosion to the banks shall be provided by means of stone pitching or riprap.
8.15 Connection to Existing Sewer Mains At the locations shown on the drawings the Contractor shall connect to the existing sewer main or existing manholes. The sewer connections may include back-drops, service diversions, punching through the wall of the existing manholes and to construct new flow-through fittings in each manhole base to accommodate the new sewer line as required. Actual connection between the existing piping and new piping shall not be made until the new work has been approved by the S.O.
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8.16 Manholes At each change of gradient or direction, at each intersection with other sewers and at such other points as shown on the drawings or as directed by the S.O., a manhole shall be constructed to the form and to the dimensions shown on the drawings. Manholes are to be constructed in circular precast reinforced concrete sections as shown on the drawings and as directed by the S.O. The bases of all manholes sections shall consist of concrete of the full thickness shown on the drawings. Channel inverts shall be accurately laid to meet pipe invert elevations at the same time as the sewer pipes are laid, the bends being as “slow” as possible by siting the manholes “off-center” at changes in direction. Short lengths of pipe with flexible joints (not more than 1m) shall be provided immediately upstream of the inlet cut pipe and immediately downstream of the outlet cut pipe for flexibility. Precast concrete manhole sections shall conform in all respects to BS 5911. The dimensions of the chambers and the shafts shall be as shown on the drawings. All joints in precast manhole sections shall be made with cement mortar. Manhole floors shall be constructed with concrete formed to the required shapes with concrete channel inverts including half round concrete channels, bends, tapers, junctions and double junctions. The top of the in-situ benching shall be sloped back at 1 in 12. Precast manholes shall be encased with concrete as shown on the drawings. Rough shuttering shall be used for the concrete surround to manholes. All concrete used in manholes shall be made using sulphate resisting cement unless otherwise shown on the Drawings or directed by the S.O. Full evidence of compliance shall be provided to the S.O. prior to the ordering and delivery of the chamber ring and cover slab sections. On site casting of these sections is unacceptable. The manhole cover slab sections shall be heavy duty and provided with an opening tapered by 50mm over which the manhole cover and frame will be set. The slabs shall be provided with built-in lifting rings. Provision shall be made for future sewer connections to manholes by providing a box-out sealed with bricks where shown on the drawings or where ordered by the S.O. The pipes shall be laid at the levels, slopes and in the directions instructed by the S.O. Ductile iron covers, to BS EN 124 shall be laid with their frames bedded on the concrete slab of the manhole cover. Manholes covers generally shall be set to the road profile and be flush with the road surface. Manhole covers located in unpaved areas shall be set at an elevation such as to prevent the entry of surface water as directed by the S.O. Where drop manholes are indicated they shall be as shown on the drawings and shall be formed where the upstream length of sewer enters a manhole at a higher level than the manhole invert level. All pipes and fittings in drop connection shall be the same material and of the same size as the fitting in drop connection shall be the same material and of the same size as the connecting pipeline shown on the Drawings. All manholes shall be watertight on completion and where leakage is discovered the Contractor shall perform such work and provide all materials as are necessary to render such faulty work watertight. The Contractor is warned that he should expect rubbish and debris to be deposited in the manholes during the course of construction and he should take the necessary measures to ensure that the manholes are not used as rubbish and waste dumps. The Contractor shall keep pipelines and manholes clear of such rubbish and debris. Manhole openings and covers shall be located taking into account the relative orientation of the manholes, ladders, landings, sewers and benching below such that access and sewer maintenance are facilitated.
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8.17 Testing Pipelines The Contractor shall submit for the S.O.’s approval details of his proposed methods and programme for testing (including details of test equipment) and shall arrange for all tests to be witnessed by the S.O. or other person appointed by the S.O. The Contractor shall provide all things necessary for carrying out testing and cleaning including pumps, gauges, pipe connections, stop ends, and all other temporary works. Pipelines shall be properly completed and supported before being put under test except as hereinafter detailed. No testing will be permitted until ten days after thrust blocks and other holding down works have been completed. Trenches shall be left open prior to testing pipelines except as permitted by the S.O. who may lay down certain restricting conditions. In addition to any tests of individual joints or other interim tests which may be specified elsewhere the Contractor shall submit all parts of the pipelines to a final test. Notwithstanding the foregoing the Contractor may at any stage of construction, carry out such other tests as he considers desirable to check materials and workmanship on the pipeline but this shall not relieve the Contractor of his obligations to achieve successful test under the Contract. All tests shall be conducted in accordance with the requirement of MS 1228:1991 or in accordance to this section of Specification as directed by the S.O.
8.17.1 Testing – Gravity Sewers Unless otherwise directed by the S.O., all sewers shall be tested immediately upon completion of not more than 300m of sewers. One or more of the following tests for leakage due to internal pressure and infiltration shall be carried out on all gravity sewer mains. The test method shall be submitted to the S.O for approval. The Contractor shall, at his own expense, furnish all equipment and materials for making the test. Tests shall be performed before backfilling is commenced and again after backfill and compaction is completed, and after all utilities are in the ground including sewer laterals, but prior to placing of permanent resurfacing. Tests shall be performed in the presence of the S.O., and shall include the main and laterals as a unit. All pipes are to be clean and empty at the time of testing. When leakage of infiltration exceeds the amount allowed by the specifications, the Contractor shall re-open the trench and repair the defect or defects until the length of sewer pipes has been retested in order to reduce the leakage or infiltration to the specified limits to the satisfaction of the S.O. However, any individual detectable leaks shall be repaired, regardless of the results of the test. Leakage tests shall be made on completed gravity sewer lines as follows: a.
Leakage Due to Internal Pressure (Air Pressure Method), the Contractor shall plug all pipe outlets with suitable plugs, and brace each plug securely where needed. The input air supply shall be regulated by a pressure regulating valve so as to not exceed 34 kPa gauge pressure. The air test equipment is to be approved by the S.O. prior to testing, the test shall be performed as follows:
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Air shall be added slowly to the pipe until the internal air pressure is raised to 27 kPa gauge pressure, at which time the flow of air into the pipe shall be shut off and the input supply hose disconnected completely from the testing equipment. After the internal pressure of 27 kPa is obtained, two minutes shall be allowed for the air temperature to stabilize within the pipe. Sufficient air is admitted as needed only to reattain a pressure of 27 kPa, timing shall start and the seconds counted until the pressure has decreased to 17 kPa. Minimum permissible pressure holding times for sewer mains, with or without laterals, are listed in the N.C.P.I. Air Test Tables, as published in the latest National Clay Pipe Institute: “Low Pressure Air Test and Sanitary Sewers (Procedures and Tables)”. b.
Leakage Due to Internal Pressure (Water Pressure Method), the S.O. may require in some cases to have certain sections of sewer pipes tested by water pressure in lieu of the Air Pressure Method. This test shall be performed as follows: The pipeline to be tested shall be plugged at all pipe outlets with suitable plugs, and each plug securely braced where needed. The pipeline shall be filled with water, and sufficient time will be permitted to elapse between the filling and testing of the line to permit absorption of water by the pipe walls. A hose shall connect the plug with a standpipe (30 cm diameter approximately). The standpipe will be filled to a level not less than 1.2m above the level of the sewer at the upper end and positioned to permit the addition of 3.8 additional litres of water. 3.8 litres of water shall be added and the time measure for the water level to return to the mark measured. The time so measured shall not be less than that computed by the following formula which provide for minimum allowable leakage of 20 litres per milimetre diameter per kilometer per day. Minimum Time (minutes)
c.
=
273,500 Diameter(mm)xTest Length(m)
Leakage Due to Infiltration, in the construction of a section of sewer of any size, excessive groundwater is encountered, a test for infiltration shall be conducted if ordered by the S.O. The upper end of the sewer shall be closed sufficiently to prevent the entrance of water, and pumping of water shall be discontinued for at least 3 days prior to the test for infiltration. The infiltration shall not exceed 20 litres per millilitre diameter per kilometer per day of that portion of main line sewer in groundwater being tested and does not include the length of house laterals entering that section. This test may be conducted in lieu of, or in addition to the other tests, as determined by the S.O.
8.17.2 Testing of Force Main (Hydraulic Testing) a.
When a section of pipeline of about 300 metres has been laid, jointed and partly backfilled as specified, it shall be prepared for testing by sealing the open ends temporarily with caps. For this purpose the contractor shall prepare “test end” units consisting of short lengths of pipe permanently fitted with caps to the satisfaction of the S.O. These units shall be jointed to the section of pipe to be tested with a standard coupling which can be easily removed when the tests have been completed thus enabling the “test end” unit to be provided with a valve outlet complete with pressure gauge shall be tested commences at a sluice valve,
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the valve may be used in place of the “test end” section to close this end of the section during test. The ends of the section of pipe under test shall be braced to withstand the end thrust which develops from water pressure; temporary thrust blocks shall be provided by the contractor for this purpose. The thrust blocks specified for the pipeline shall be permanently constructed in place and the concrete properly cured before the test is made. No temporary bracing will be permitted in place of thrust blocks since the purpose of the test includes the testing of permanent thrust blocks and fittings in addition to pipes. b.
The section of pipe to be tested shall be filled with water of fair quality, free from sediment from a source approved by the S.O. The water shall be introduced into the pipeline through the valve in “test end” unit at the lower end of the pipeline. During filling, provision shall be made for air to escape from all high spots in the pipeline and from the valve in the upper “test end” unit. If the pipeline is on a level grade, it may be necessary to provide temporary tees and air valves on the main at several points to ensure the escape of air. The tees shall be blanked off after the test is applied. If the main runs up-hill, the pressure gauge used during tests should be situated at the bottom of the section, otherwise excessive pressure may be imposed upon the lower part of the pipeline and there will be a risk of damage to anchorages designed to withstand the specified test pressure. This pressure shall be applied by means of force pump at the highest convenient point on the main so as to minimize the pressure against which the pump will have to operate. The test section shall be completely filled with water for at least 24 hours prior to testing to allow for absorption of water into the pipes and/or jointing material.
c.
Water shall be pumped into the main raising the pressure slowly in increments of 1 bar, with pauses of one minute between each increment. Should any appreciable drop in pressure be noted during one of these pauses the test shall be stopped until the cause of the pressure drop has been investigated and rectified. The pipes shall be tested to one and a half times the working pressure. The pressure/strength test shall be considered to have been passed when the pressure gauge shows no reduction from the test pressure during the period of ten minutes after full pressure has been attained.
d.
The leakage test shall then follow. The pressure shall be held at one and a half times the working pressure and maintained as constant as possible for a period of twenty-four hours by pumping in make-up water if necessary. The leakage test shall be considered to have been passed if the measured quantity of make-up water pumped into the pipe to maintain the test pressure does not exceed 0.1 litre per millimetre (mm) of pipe diameter per Kilometre (km) of pipeline per day (24 hours) for each 3 bars of pressure applied.
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e.
Only sufficient backfilling of the trench to prevent snaking of the pipes shall be allowed before the satisfactory completion of these tests detailed above.
f.
Every section of the pipeline shall be tested and connected with all previously tested sections so that no element of the pipe line is left untested.
g.
All ductile iron pipes and fittings within pump stations shall also be similarly tested for strength and leakage, but the Contractor shall take adequate precautions to strengthen and secure joints, bends, tees, etc. so that they are not damaged during the tests. All pipes and fittings which prove defective shall be remedied or repaired and tests repeated until satisfactory result are obtains. The contractor shall repair any damage resulting or caused by these tests at his own expense. Pumps to be used in the works shall not be subjected to hydrostatic pressure during the tests.
8.18 Sewer Inspection, Condition Assessment and Classification All network sewers shall be 100% internally inspected after all other tests on the sewer have been completed and prior to hand-over. Sewers 1200mm diameter and larger may be inspected manually by man entry. Otherwise all sewers shall be examined by closed-circuit television (CCTV) inspection. Sewer inspection shall also comply with all the relevant requirement of MS 1228. Only certified operators shall carry out CCTV inspection. Valid calibration certificates shall be produced for all CCTV equipment to be used for the inspection. The sewer condition assessment and classification report shall be endorsed and submitted by an accredited assessor. The assessment and classification shall be strictly in accordance to the Manual of Sewer Condition Classification (4th Edition) published by WRC, United Kingdom. Acceptance or otherwise of the sewers shall be based on the requirements of Malaysian Sewerage Industry Guidelines Volume 3. Any sewer found not meeting the acceptance standard shall be repaired and the reinspected. This process shall be repeated until the repaired sewers meets the acceptance for the sewer. Old sewers shall be Grade 2 or better while new sewers shall be Grade 1.
8.19 Test for Straightness Tests for straightness for pipes equal to or less than 750mm diameter shall be applied on a section of pipeline between two manholes by means of a mirror at one end of the sewer and a lamp at the other. The sewer will have passed the test if a full circle of light is observed. For pipes having diameters greater than 750mm, the permissible deviation from true alignment shall not be more than 50mm measured from plan.
8.20 Cleanliness of Sewers and Force Mains The pipes shall be kept thoroughly clean and an adequate supply of expanding rubber plugs shall at all times be available to ensure that all pipe ends are stopped off. Except when water testing, water shall not be allowed to flow through the pipes. The Contractor shall make all necessary provision for disposing of drainage water during the execution of the Works by means of channels, troughs or other
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approved methods. Before the issue of the Certificate of Completion, a train consisting of an approved badger and a circular rubber squeegee shall be passed through each length of sewer, and this shall be followed by a wooden ball, not smaller than one inch less in diameter than the pipes under inspection. The Contractor shall remove any obstruction found during these operations.
8.21 Temporary Surfacing Temporary surfacing 38mm thick shall be furnished, installed, maintained, removed and disposed of in accordance with the applicable portions of Section 306-1.12 of the “Standard Specifications for Public Works Construction, 1970 Edition” for all trenches where traffic is allowed to drive over or along the excavated and backfilled areas prior to permanent resurfacing. All costs of furnishing and installing the temporary surfacing are considered to be included in the unit rates for pipe and no additional compensation will be allowed.
8.22 Liability in Pipe Installation Pursuant to the relevant Clause in the Conditions of Contract, the Contractor shall be liable to the Employer for any damage caused to the pipeline or to pumps and other equipment of the Employer as a result of foreign matter of any kind not having been cleaned out of the pipeline before it is handed over to the Employer.
8.23 Maintenance in Pipe Installation Work One month before the end of the Contract Maintenance Period, the Contractor shall inform the S.O. of the expiry date and arrange for the leaning up and ventilation of the Works and the provision of all necessary ladders, etc., required for inspection of the works by the S.O. accompanied by the Contractor or his representative. Any default resulting from faulty materials or workmanship used in the execution of the works shall be rectified by the Contractor at his own cost to the satisfaction of the S.O.
8.24 Sewer Connections to Existing Properties The Contractor will not be permitted to start work on the sewer connection to any property until all the downstream sewers, pumping stations, pumping mains, and disposal facilities are sufficiently completed to receive the flow to the satisfaction of the S.O. The S.O.'s judgement shall be final and no claim for delay or additional monies will be entertained resulting from the incomplete status of the Permanent Works downstream. All sewer connections shall be constructed of vitrified clay pipe unless otherwise instructed by the S.O. The Contractor shall lay new sewers and house connections and construct new chambers and manholes, as required to divert sewage and waste-water flows from existing properties as shown on the Drawings or as instructed by the S.O. to the main sewers constructed under this Contract. The work shall be carried out in accordance with the details shown on the Drawings or as directed by the S.O. on site. The location of sewers, manholes and chambers to be constructed under this Contract is indicated on the Drawings and will be confirmed by the S.O. on site.
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Section 8 - Sewer, Force Mains, Pipelaying, Manholes and Appurtenances
In general, the existing properties to be connected under this Contract have existing septic tank facilities. The location of these tanks, where known, is indicated on the Drawings. The Contractor shall confirm the location of each septic tank. Precise connection arrangements will be as directed by the S.O. on site. The Contractor should allow for modifications to the sewerage arrangements to individual properties in those instances where no septic tank is in existence. After the diversion works for each group of buildings have been finished, the Contractor shall remove and dispose of the contents of the existing septic tanks, and break out the slabs and walls of the tank to a depth of at least 500 mm below ground level. The Contractor shall backfill the tanks with approved compacted backfill and reinstate the surface with turf, topsoil, concrete and macadam or otherwise as directed by the S.O. to its original condition. The Contractor shall remove all debris from the Site and leave the area in good condition to the satisfaction of the S.O.
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Section 9 - Building Works
9.0
BUILDING WORKS .....................................................................................9-1 9.1
Brickwork .........................................................................................9-1 9.1.1 Bricks .....................................................................................9-1 9.1.2 Mortar.....................................................................................9-1 9.1.3 Bricklaying.............................................................................9-2 9.1.4 Joints .....................................................................................9-2 9.1.5 Ties.........................................................................................9-2 9.1.6 Wall Reinforcement...............................................................9-3 9.1.7 Damp-Proof Course ..............................................................9-3 9.1.8 Lintels ....................................................................................9-3 9.1.9 Building-In .............................................................................9-3 9.1.10 Chases in Brickwork.............................................................9-3 9.1.11 Protection of Finished Work ................................................9-3
9.2
Stone Work.......................................................................................9-3 9.2.1 Stone ......................................................................................9-4 9.2.2 Mortar.....................................................................................9-4 9.2.3 Uncoursed Square Rubble ...................................................9-4
9.3
Carpentry and Joinery.....................................................................9-4 9.3.1 Codes of Practice..................................................................9-4 9.3.2 Materials ................................................................................9-4 9.3.3 Fixings and Fastenings ........................................................9-5 9.3.4 Workmanship ........................................................................9-6 9.3.5 Timber Architraves ...............................................................9-7 9.3.6 Timber Doors.........................................................................9-7 9.3.7 Hardware................................................................................9-8 9.3.8 Partitions .............................................................................9-10 9.3.9 Toilet Partitions ...................................................................9-10 9.3.10 Bench and Cupboard Fitments ..........................................9-10 9.3.11 Overhead Shelving..............................................................9-11
9.4
Metalwork .......................................................................................9-11 9.4.1 Aluminium Framed Windows and Doors ..........................9-11 9.4.2 Double Glazed Windows ....................................................9-13 9.4.3 Security Grilles to Window of All Stores...........................9-13
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9.4.4 Roller Shutter Doors ...........................................................9-13 9.4.5 Acoustic Doors....................................................................9-14 9.5
External and Internal Finish..........................................................9-14 9.5.1 Suspended Ceilings............................................................9-14 9.5.2 Finishes to Brickwork.........................................................9-16 9.5.3 Ceramic and Glass Mosaic.................................................9-17 9.5.4 Glazed Wall Tiling ...............................................................9-17 9.5.5 Acrylic Spray Tile and Coating ..........................................9-17 9.5.6 Sound Absorbent Wall Lining ............................................9-18 9.5.7 Floor Finishes - General .....................................................9-18 9.5.8 Preparation of Applied Finishes ........................................9-18 9.5.9 Marble Slabs ........................................................................9-18 9.5.10 Carpet Tiles .........................................................................9-18 9.5.11 Raised Modular Floor .........................................................9-18 9.5.12 Ceramic Tiles.......................................................................9-18 9.5.13 Homogeneous Tiles ............................................................9-19 9.5.14 Granolithic Finish................................................................9-19 9.5.15 Pebble Washed Finish ........................................................9-19 9.5.16 Quarry Floor Tiles ...............................................................9-20 9.5.17 Concrete Floor Hardener ....................................................9-20 9.5.18 Mosaic Tiling .......................................................................9-21 9.5.19 Terrazzo Tiling.....................................................................9-21 9.5.20 Vinyl Tiles ............................................................................9-22 9.5.21 Slate .....................................................................................9-22 9.5.22 Skirting.................................................................................9-22
9.6
Roofing ...........................................................................................9-22 9.6.1 Roof Waterproofing ............................................................9-22 9.6.2 Roof Insulation Material .....................................................9-23 9.6.3 Metal Roof Decking and Roofing Sheets ..........................9-23 9.6.4 Interlocking Concrete Roof Tiles .......................................9-24 9.6.5 Asbestos Cement Roofing Sheets.....................................9-25 9.6.6 Roof Fascia..........................................................................9-25 9.6.7 Roof Drainage......................................................................9-25
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9.7
Glazing............................................................................................9-26 9.7.1 Glazing and Fixing Glass ...................................................9-26 9.7.2 Frameless Glass..................................................................9-26 9.7.3 Mirrors..................................................................................9-26 9.7.4 Cleaning and Replacement ................................................9-27
9.8
Sanitary Plumbing .........................................................................9-27 9.8.1 General.................................................................................9-27 9.8.2 Fixture Outlet.......................................................................9-27 9.8.3 Jointing and Supporting Pipes ..........................................9-28 9.8.4 Sanitary Fixtures .................................................................9-28 9.8.5 Testing Sanitary Plumbing .................................................9-29 9.8.6 Floor Waste .........................................................................9-29 9.8.7 Sanitary Fittings ..................................................................9-29
9.9
Cold Water Plumbing.....................................................................9-29 9.9.1 General.................................................................................9-29 9.9.2 Isolating Valves ...................................................................9-30 9.9.3 Installation of Taps and Outlets.........................................9-30 9.9.4 Ironmongery ........................................................................9-30
9.10
Hard core ........................................................................................9-30 9.10.1 Material and Laying.............................................................9-30
9.11
Building Acoustic Treatment ........................................................9-30
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9.0 BUILDING WORKS 9.1
Brickwork
9.1.1 Bricks Approved Manufacturer Bricks whether facing or common shall be from an approved manufacturer and shall be hard, sound, well-burnt, machine made wire-cut bricks or pressed bricks of regular and standard size. Bricks shall be regular in size and shape, with good faces and clean arrises, sound and free from cracks and any other defects. Facing bricks shall be of the colour selected by the S.O. Common Bricks The common bricks, unless otherwise described, shall be wire cut clay bricks, even in size, smooth in texture and with sharp well defined arrises. Clay bricks shall conform to BS 3921 with a minimum compressive strength of 20 N/mm2. Facing Bricks The facing bricks shall be hard, well burnt, machine made, wire cut Clinker bricks with a vitreous finish, of size 215 mm x 102.5 mm x 65 mm approximately and from an approved source. They shall all possess the same colour and texture and shall not exhibit any efflorescence. Calcium Silicate Bricks Calcium silicate bricks shall comply with the requirements of BS EN 771-2, Class 3 with a minimum compressive strength of 20.5 N/mm2. S.O. Approval Before bricks are ordered, samples shall be submitted to the S.O. for approval. The approved samples shall be kept on the site for reference. Delivery shall be kept strictly to the approved samples. On delivery to Site, bricks shall be stacked to the approval of the S.O. All rejected brick shall be removed from the site forthwith at the Contractor’s own expenses.
9.1.2 Mortar Brickwork in buildings shall be set in 1:1:6 cement-line-sand mortar. Brickwork in manholes and elsewhere shall be set in 1:3 cement sand mortar. Lime for use with mortar shall be semi-hydraulic (calcium) lime or non-hydraulic (calcium) lime complying with the requirements of BS EN 459-1 Mortar shall be machine mixed on site only as required immediately prior to use, and any mix which is over 3/4 hour old shall be rejected. Under no circumstances shall a type of sand be changed during the course of the work. Where handmixing is permitted, mixing shall be carried out on an approved waterproof platform. Materials for mortar shall comply with the requirements as follows:Sand - clean, sharp, best quality bricklayers sand containing not more than 5% of clay and shall be obtained from approved source.
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Cement - Portland cement, fresh and of an approved brand complying with BS EN 197-1 Water Fresh, clean of potable quality, free of vegetation and other deleterious matter, and shall comply with BS EN 1008. Materials for mortar for brickwork shall be measured by volume and shall consist of 3 parts sand and 1 part cement. Plasticising additives shall not be used without prior approval from the S.O.
9.1.3 Bricklaying Codes of Practice Workmanship shall generally comply with the requirements of BS 5628: Part 3 – “Use of Masonry” subject to any qualifications given below. Bricklaying shall be carried out such that cutting of bricks is reduced to the minimum by careful setting out. Brickwork shall be set out accurately to the various dimensions, thickness and heights shown on the Drawings. Before commencing work, storey rods showing the heights of all courses shall be set out and these shall be strictly followed. All brickwork shall be plumb within 5mm of plane and level over a distance of 3 metres in any direction. Brickwork shall be built English bond for walls one brick thick and over, stretcher bond for walls half a brick thick. All bricks shall be well soaked before use and during hot or dry weather to avoid undue absorption of moisture from the mortar, but shall not be left standing in water or be brought otherwise to a saturated condition. Bricks shall be damp as necessary and the top of walls left off shall be damp before work commences. All walls shall be kept to a fairly uniform height and at no point shall brickwork in the same wall unit be carried up more than five (5) courses above any adjoining portion. Before commencing any work, the bricklayer shall confer with other trades to ensure that all pipes, conduits, bolts, frames or any other materials necessary to be installed in the work at the time it is built, has been fixed or provided for.
9.1.4 Joints Beds and vertical joints of brickwork shall be filled solid with mortar, and no vertical joint shall be allowed to be flushed up from the top but each joint must be filled up as the bricks are laid. All work found not to comply strictly with this requirement shall be taken down and rebuilt at the Contractor’s expenses. Joints shall not be more than 6mm thick and all joints shall be raked out to a depth of 12mm to form a key for plastering as the work proceeds. The courses shall be laid truly level and at the time or bedding all joints shall be neatly struck with a trowel. Suitable pointing of an approved colour shall be made on all joints with facing bricks.
9.1.5 Ties
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All brickwork adjacent to reinforced concrete shall be bonded to the concrete structure with approved ties set at every fourth course. The ties shall be adequately secured to the main reinforcement in the concrete. Where facing brick is required for the external face and common brick is required for the internal face of brick walls, the two thickness of brickwork shall be bonded together with wall ties spaced 900mm apart horizontally, 450mm vertically and staggered and with extra ties at reveals and openings.
9.1.6 Wall Reinforcement Reinforcement shall be of approved galvanised steel expanded metal lath set at every fourth course. Wall reinforcement shall be lapped with the column ties. Wall reinforcement shall be laid in continuous long lengths and shall have minimum lap of 350mm at joining and bent around at angles and intersections. The reinforcement shall be discontinued at control joints.
9.1.7 Damp-Proof Course Damp-proof course shall be of the best quality 6 mm thick three ply bitumen impregnated and approved by the S.O. Damp-proof course shall be laid in continuous length of appropriate width in a 12mm thick mortar bed one course above ground floor level. A minimum lap of 100mm shall be provided where necessary.
9.1.8 Lintels Unless otherwise shown all brickwork over openings shall be supported on precast concrete lintels in accordance with the dimension shown on the Drawings or as directed by the S.O.
9.1.9 Building-In Generally and wherever practical, all items shall be built in as work proceeds. The Contractor shall ensure all built in items are preprimed as required, set and braced into correct position, have all building-in provisions properly fixed, reinforced to prevent distortion and protected against damage.
9.1.10 Chases in Brickwork Chases shall be cut in brickwork where instructed by the S.O. to accommodate cables and conduits for electric lighting, power and instrumentation.
9.1.11 Protection of Finished Work All decorative elements, finished surfaces, particularly corners and jambs shall be protected with timber casing or other suitable means as soon as they are built. Newly erected brickwork shall be protected against weather to prevent the mortar from being washed out of the joints. Should any brickwork become damaged by sun or rain the brickwork so damaged shall be removed by the Contractor and rebuilt at no extra cost to the Contractor.
9.2
Stone Work
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9.2.1 Stone Stone material, selected colour and texture shall be approved by the S.O.
9.2.2 Mortar The material for mortar shall be as previously specified for brickwork. The fine aggregate shall preferably be composed of crushed stone of the stone type selected.
9.2.3 Uncoursed Square Rubble Stone work shall be in uncoursed square rubble. It shall be roughly dressed, square laid with all horizontal joints. Maximum height for stone shall not exceed 250 mm.
9.3
Carpentry and Joinery
9.3.1 Codes of Practice Carpentry works shall generally comply with the requirements of BS 5268 subject to any qualification given below. Joinery works shall generally comply with the requirements of BS 1186 and BS EN 942, subject to any qualification given below.
9.3.2 Materials Where specified, codes and standards shall be taken as a guide only as minimum in quality and performance. Any materials which do not comply with these requirements or which in the opinion of the S.O. are defective or damaged by exposure or other causes shall be removed from the site. a)
Timber
Timber for use in permanent work shall be primary hardwood first class Chengai, Merbau, Bakau or Resak or as specified on the Drawings and shall be the best quality suitable for the particular purpose and shall in all cases be thoroughly seasoned, sound, dry straight and free from large loose or dead knots, injurious shakes, sap, shakes, dogmarks or other defects. Well seasoned and tanalised meranti may be used for furniture and wall panels. Moisture content of all timber shall not exceed 15%. Timber shall be sawn into scantlings not less than one month before use, such that the scantlings will be of the specified dimensions after planning and preparing. Unless otherwise directed, all woodwork exposed to view shall be wrought and prepared for painting unless otherwise specified. All timber shall be unused and shall be properly stacked and protected from the weather. All defects appearing in joinery work such as warping, twisting, opening of joints, etc. shall be remedied either by refitting or by substitution as required, at no extra charge.
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All timber for permanent works shall, except where otherwise specified, be pressure impregnated with an approved wood preservative after planning and preparing. The quantity of preservative used per cubic metre of timber shall be fully in accordance with the manufacturer's recommendations. All surfaces cut after preservative treatment shall be brushed with two coats of an approved preservative. All secondary hard wood timber shall also be treated with approved pressure preservative and all timber shall be primed before delivery to the Site for fixing. b)
Plywood
All plywood in doors, fitments or panelling shall be manufactured from hardwood and in compliance with BS 6566: Grade II on both faces and shall be of Weather and Boil Proof Quality. Marine plywood shall comply with the requirements of BS 1088. Each sheet of plywood delivered to the site shall bear the following markings: • • • • •
Manufacturer’s name or identification BS EN 636 W.B.P (Weather and Boil Proof) Grade of Finish Thickness
Plywood shall comprise resin bonded multiple veneer plywood and of thickness specified, finished in matched veneers on both sides. All plywood exposed to weather or in washrooms shall be waterproofed plywood and shall comply with BS EN 636.
9.3.3 Fixings and Fastenings All nails, screws, spikes, bolts, etc. are to be of the best quality and of the weights and lengths suitable for the purpose required. a)
Nails for carpentry work or for fixing steel to timber shall be galvanised.
b)
Screws shall be countersunk for fixing accessories to timber.
c)
Brass screws shall be chrome plated and countersunk, raised or dome head for fixing sanitaryware and similar accessories.
d)
Engine bolts shall be hexagonal head for fixing timber to steel.
e)
Masonry anchors shall be of expanding screw type in lead in pre-drilled or formed holes grouted in cement mortar.
f)
Explosive powered steel pins into concrete or steel may be used only if specifically approved by the S.O.
g)
Bolts and screws shall be completed with nuts and washers as appropriate.
Proprietary fixing Various proprietary fixings are available for particular or specialised jobs. These shall only be used where appropriate in accordance with the manufacturer’s instructions and to approval of the S.O. when not specifically detailed.
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Where holes are required for fixings, their formation in metal or synthetic materials shall be by drilling and in brick, stone or concrete shall be by percussion methods i.e. jumper and hammer. Where cartridge operated hand tools are used such as “Ramset” or similar approved, performed holes are not required. They must not be used on ceramic tiles, hollow blocks, cast iron and other brittle material, lath and plaster, fibre board and similar soft materials. Fixing of timber to concrete or brickwork shall be by: a)
Hardened steel pins direct into concrete or brickwork for fixing small sections such as skirtings and architraves. The head shall be punched home-and filled.
b)
Preformed plugs such as “Rawlplug” or similar approved informed holes.
c)
Plastic compounds such as “Philplug Fixrite” or similar approved in-formed holes
d)
Expanding bolts such as “Rawlbolt”, “Expandabolt” or similar approved
e)
Catridge operated hand tools such as “Ramset” or similar approved but shall not be used within 50mm of any edge.
9.3.4 Workmanship a)
Storage of materials
All timber, asbestos-free cement sheeting, etc. shall be stored under a shed, and properly stacked to enable air to circulate freely around all faces on site and protected from weather until they are incorporated in the work. Any materials which deteriorate as the result of storage shall be replaced at the Contractor’s expense. Storage shall be as follows:
b)
i)
Each grade separately stored, with treated timber separate from untreated.
ii)
On levelled bearers off the ground, permitting free air circulation and preventing sagging.
iii)
Protected from weather; keep any temporary covers from close contact with the timber.
Carpentry and joinery
Carpentry and joinery shall be carried out in accordance with the best trade practice using competent tradesmen, equipment, materials and processes that are adequate for the purpose. Timber which is to be permanently incorporated into the work shall not be used for any temporary purpose. All timber members shall be new and selected for straightness. Saw cuts to relieve bowed members will not be accepted. All joints shall be secured by concealed fixings where possible. All slips, fillets, casings, wedges, blocks, etc, shall be provided where required.
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All carpentry framing shall be jointed as shown or as is most appropriate in the circumstances. The joints shall be designed and constructed so that they will transmit the loads and resist the stresses to which they will be subjected. Unless otherwise stated, all joints shall be secured by means of notching and where necessary strengthened by wood dowels. c)
Built-in work
Fitments to be built between walls and/or columns shall be based on measurements of actual completed work on site such that a neat tight junction is achieved. All joinery which is built-in shall be first primed or sealed on the faces and edges to be built-in. Where sink units or other items are built into the joinery, they shall be properly fitted and fixed prior to leaving the shop. d)
Finishing
All work shall be thoroughly sand papered leaving no machine marks or sand streaks.
9.3.5 Timber Architraves Architraves shall be provided and fixed to timber door frames. They shall be of hardwood size 25 x 12mm mitred at corners. Where door jambs are flush with the face of brickwork, architraves shall be splayed externally 38 x 18mm mitred at corners.
9.3.6 Timber Doors All hardwood used for doors shall be Grade 'A'. Door frames, unless otherwise indicated shall be of chengai or merbau, sized 150 x 50 mm rebated as shown to form door stops. Doors shall be of type, size and thickness as indicated on the Drawings and shall be of first quality construction. Doors shall be obtained from one manufacturer as approved by the S.O. and shall be guaranteed against any warp, wind or other defects, other than fair wear and tear. Should any defect or defects become apparent during the Defects Liability Period, the affected door shall be replaced and finished to approval at no extra cost. Unless otherwise specified, all meeting stiles of paired doors shall be rebated. Timber doors are classified as follows:
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Timber flush door It shall be 38mm thick flush doors which are surfaced with sheets of painted grade plywood fixed to a skeleton frame. The doors shall be fitted with 10mm thick primary hardwood edge strips all round in accordance with BS 459 Part 2 with top and bottom rails and styles 100 mm x 50 mm and intermediate rails 100 mm x 25 mm at 300 mm centres. The frames shall be hardwood and the facing plywood shall be manufactured with a waterproof adhesive. Door frames unless otherwise shown shall be hardwood and of minimum finished size 125mm x 75mm. Timber flush doors unless otherwise specified shall be used for all internal doors. Decorative laminates shall be provided in accordance to the drawings where necessary or as requested by the S.O. Timber flush door Timber flush doors that used for doors of toilets, tea rooms, etc, where such doors are in contact with water shall be surfaced with sheets of waterproof grade plywood on both sides. Solid Timber Door It shall be 38mm solid primary hardwood core flush doors lined with waterproof plywood unless otherwise specified. All external wooden doors shall be solid timber doors. Solid Timber Door (1-hour fire rated) It shall be 1-hour fire resistant doors made of solid primary hardwood and surfaced with plywood all approved by the Fire Authority. Should timber door is used as internal doors of stores, it shall be 1hour fire rated. Solid Timber Door (2-hour fire rated) It shall be 2-hour fire resistant doors made of solid primary hardwood and surfaced with plywood all approved by the Fire Authority. Should timber door is used as internal doors of electrical switch rooms, battery rooms, etc it shall be 2-hour fire rated.
9.3.7 Hardware Hardware shall be fixed with screws and accessories of matching finish in a manner appropriate to the item and in accordance with the manufacturer's instructions. a)
Locks, Latches and Door Furniture i)
Locks
Locksets shall be of `Vachette' of satin stainless steel finish as approved by S.O. The quality of lock All locks shall be of the appropriate functions and operation as recommended by the Manufacturer. Locksets for toilet doors shall be of “Whitco” or equivalent as approved by S.O. complete with all necessary accessories. Each lock shall be supplied with three keys. All locks shall be mastered keyed of two systems, namely one for external doors and another for internal doors. Four master keys shall be supplied for each system.
ii) Latches
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Latches shall be heavy duty tubular type of stainless steel as approved by S.O. iii) Door Furniture Door furniture shall be of the highest quality, fitted with matching screw and supplied by an approved manufacturer. Door furniture shall be as follows unless otherwise stated in the drawings or subject to any modifications as required by the S.O:
External single leave door: • Single cylinder upright mortise nightlatch • Handles on plates External double leaves door: • Lever handle • Cylinder rim nightlatch, 230mm grip handle on outside of leading leaf, 300 mm barrel bolt at bottom and top of following lead. Internal single leave doors: • Lever mortise lock • Lever mortise lockset. Internal double leave doors: • Leading leaf as for single door. • 300 mm barrel bolts at top and bottom of following leaf. Sliding doors: • With swing leaf - cylinder rim nightlatch. handle on each side of door, 450mm barrel bolt. • 230mm grip • Without swing leaf - cylinder rim nightlatch with sliding locking bar. 230mm grip handle on each side of door, 450mm barrel bolt. W.C. door: • Brass indicating bolt b)
Door closers Provide and fix ”Lokwood” design or approved equivalent of appropriate types, sizes and weights to all fire-rated doors and doors of air-conditioned Rooms, Control Rooms, Evaporator, and Chlorinator Rooms and entrance doors to toilets and tea rooms.
c)
Accessories (Hinges, Bolts, etc.) Internal doors shall generally be hung on 3 Nos 100mm stainless steel loose pin butt hinges. Barrel bolts for the tops of doors shall be provided with suitable top plates, and those for the bottom of doors with cleanable sockets. Internal and external door furniture shall have a satin anodized aluminium.
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Door stops, door hooks, door and kicking plates shall be provided for each door in materials compatible with the door furniture.
9.3.8 Partitions Gypsum board partitions shall be of `Fabwall' slimline demountable partitions or approved equivalent. Full height partitions shall be covered with selected `3M Scotchgard Tapetex' linen wall covering or approved equivalent on both sides. Gypsum boards of half-glazed partitions shall be similarly covered. All partitions shall be complete with all necessary aluminium door frames, heads, trimmings & skirtings in anodised finish. All full height partitions of individual offices including doors shall be sound insulated with approved heavy density fibreglass blankets.
9.3.9 Toilet Partitions Toilet partitions shall be `Moflex' partitions of `Ardmoe' model or approved equivalent complete with all necessary accessories where specified in the Drawings.
9.3.10 Bench and Cupboard Fitments All cupboard and fitment dimensions shall be determined accurately by the joiner on site. Fitment dimensions as relevant shall be checked on site. All work shall be carried out by an experienced joinery firm. All materials and workmanship shall be of the highest standard. Generally all exposed finish shall be varnished with three coats of ICI Timber Tone or equivalent paint. Top of bench and of floor standing shelf shall be finished with selected plastic laminate of 1.2mm thickness. Unless otherwise directed by the S.O., the construction of cupboards and fitments shall be as follows:a)
Framing and supports shall be ex 75 x 25 mm hardwood timber.
b)
Minimum 25mm thick veneered plywood to be used for tops, bottoms, ends, intermediate vertical partitions and shelves. Exposed edges shall be finished smooth and painted.
c)
Backing of all cupboard shall be of 18mm thick plywood.
d)
Each cupboard door shall be hung with brass hinges with approved 75mm `D' pull handles.
e)
Drawers shall generally have fronts ex 25mm timber and sides and backs ex 18mm, all ploughed to receive 9mm waterproof plywood at bottom.
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Drawers shall be fitted with approved drawer slide runners with stops and `D' pull handles, similar in pattern as for cupboard doors.
9.3.11 Overhead Shelving Overhead shelf shall be of 18mm thick waterproof plywood with 10mm deep edge all round, properly varnished to approved colour. Shelf shall be supported on 4 Nos 150mm x 4mm thick galvanised mild steel angle brackets concealed behind wall lining. The brackets shall be securely fixed to the wall and to the under side of the shelf.
9.4
Metalwork
9.4.1 Aluminium Framed Windows and Doors Window frames casement, sashes, door frames, etc., unless otherwise specified shall be constructed of extruded aluminium alloy B6063-T5 sections or equivalent and anodised in bronze colour in accordance with BS EN12373-1 to give a minimum coating thickness of 10 microns. Aluminium surfaces shall be anodised with a clean satin sealed finish throughout. Where polyester powder coating is required, it shall be corro-coat PE-F to BS 6496 in any approved colour and shall be applied by an approved applicator strictly in accordance with the manufacturer’s specification and instructions. The film thickness for the polyester powder coating shall be 65 + 15 microns. All aluminium window frames shall be supplied with continuous extruded aluminium finger pulls and complete with approved fixing, locking and hanging devices, handles and/or pegs and stays. The perimeter of the windows shall be fixed with an approved waterstrip. Windows shall be lourved, top hung and side opening types and fixed glass types unless otherwise shown on the drawings. Window frames for fixed glass louvres shall have weathering jambs, heads and sill of minimum 102 x 45 mm with fixed clips to receive minimum 225 mm glass blades and with removable insectproof screens in aluminium frames at the rear, unless otherwise specified. Adjustable louvers shall whenever necessary be provided complete with extension arms and cranks to permit adjustment from shoulder level. Window frames for fixed aluminium louvres shall have weathering jambs, heads and sills of minimum 102 x 45 mm to admit sufficient light to interior, unless otherwise specified. All aluminium frames shall be obtained from an approved manufacturer by the S.O. The whole assembly by its design, flashing and calking shall be completely waterproof, watertight and insectproof under in-service condition. Fixed louvers windows and doors shall be provided complete with insect screens. The Contractor shall submit designs and samples of the materials and assembly to the S.O. for approval prior to fabrication. Operating gear or mechanism to sashes shall be of such design as will adequately and easily control the airway of an opening sash by manual control within easy reach of the floor.
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Satisfactory hardware and operational gear shall be provided to perform the functions for which it is intended and in such a manner as will ensure adequate safety to the ordinary user in operation. Sashes shall not be removable from outside of the building. Screws, nuts, washers, bolts, rivets and other fastening devices incorporated in window units shall be of stainless steel and shall be of sufficient strength to perform the functions for which they are required. Glazing rebates shall be not less than 16 mm deep and sufficiently wide to provide adequate glass clearance and where glass dimensions exceed 650 mm, neoprene spacers are to be used. Glazing beads shall be sufficiently heavy to maintain adequate pressure on spacers and shall be held in position by aluminium or stainless steel screws or by approved snap-in type grooves, all with provision for adjustment. Hardware shall be designed to perform the functions for which it is intended and shall be securely attached to the units. Component parts shall be of bronze, brass, stainless steel or other non-corrosive material compatible with the parent metal and of sufficient strength for the intended function. All items of hardware shall be approved by the S.O. Provision shall be made for hinges, locks, catches, handles, furniture, latches, opening, devices and pulls required for efficient use and operation. The provision of trimming members shall be incorporated in the design and construction of units as necessary to suit the architectural requirements specified. Expansion and construction of the member of frame must be able to take place freely. Under no circumstances will the provision for expansion be allowed by slotting the fixing holes in brackets to allow sliding movement between the brackets and the building structures. Wherever possible all metal shall be formed, cut, drilled, tapped, welded, fitted or otherwise fabricated in the shop. Fixing lugs of all metal sub-frames shall be suitably galvanised or primed with zinc chromate before building in. The units shall be set plumb, square and level and shall be built into openings prepared for this purpose and shall be securely held in correct vertical and horizontal alignment.
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Side Hung Aluminium Casement Door and Window Frames: All aluminium side hung/swing door and window frames shall be supplied with continuous extruded aluminium finger pulls and complete with approved fixing, locking and hanging devices, handles and/or pegs and stays. All doors shall be hung on approved floor springs and shall be complete with horizontal aluminium bar openers and approved locks. The perimeter of the windows shall be fixed with an approved waterstrip. Top Hung Aluminium Casement Window Frames (Vertically and Horizontally Pivoted Windows): All vertically and horizontally pivoted window shall be provided with friction side arms to allow the opening of the vents in any desired positions without the need for pegs stays. Handles shall be provided for locking the windows from the inside.
9.4.2 Double Glazed Windows Double glazed windows shall be hermetically sealed double glazed type in powdered coated aluminium frames for sound insulation purpose. The sound insulation value shall be not less than 40 dB for frequency of 100-3150 Hz. Tinted glass of 6 mm thickness shall be separated for a distance not less than 200 mm apart and the surfaces of the interspace shall be lined with sound absorbent material. The sashes shall be sealed. The Contractor shall submit his design and sound reduction data for approval by the S.O. before manufacturing.
9.4.3 Security Grilles to Window of All Stores 'Amplimesh' aluminium grilles type 103 panel shape in powder coated finish shall be provided to all aluminium framed glass windows and louvres of all store rooms and workshops/stores of all buildings inclusive of the whole of store Building. Amplimesh shall be incorporated to the external faces of top hung/casement windows. For louvre windows, they shall be incorporated between glass louvres and removable insect screens with matching aluminium spacers and frames for fixing. The design and details of incorporation and fixing of security grilles shall be submitted to the S.O. for approval before manufacturing and incorporation.
9.4.4 Roller Shutter Doors Roller shutter doors shall be “SKB Heavy Gauge Roller Shutter” or approved equivalent by the S.O. Doors shall be operated with push button electric drive system and manual override. Roller shutter doors shall be of the multiple folds type opening vertical upwards into a roller drum which shall be housed and concealed in an aluminium cabinet. Side guides, channels and bottom rails shall be provided. Aluminium sheets used for the door shall not be less than 16 SGW thick. The door shall be operated mechanically by an endless chain through either a spur or worm reduction gear running on self lubricating bearings or ball bearings and shall have smooth action. The door curtain shall be a continuous galvanised sheet steel of 1.0 mm minimum thickness and spray painted. Where openings exceed 4800mm wide, lift-out or hinged mullions shall be provided so that access through the doors are not restricted. The doors shall be provided with locks and each lock shall be supplied with three keys. The locks shall be of stainless steel.
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9.4.5 Acoustic Doors The doors shall comprise flush panel steel door leaf not less than 63mm thick and shall be factory hung in a four sided steel frame, complete with acoustic edge seals and the necessary furniture and hardware. The door frames shall be pressed from galvanised mild steel not less than 16 gauge (1.5 mm) thick to form a 75mm architrave faced section suitable for a 112mm thick brickwall. The door faces shall be completely flat and free of buckle. Door hinges shall be of stainless steel. The doors shall be capable of opening through 180 degrees except where limited by contact of the door or door closer with the adjacent walls. Pre-tapped holes in the door and frame shall be provided to accommodate the door hardware, furniture and door closers as required or as shown on the Drawings. The doors shall be supplied prime coated after washing down with lithoform and shall be painted after installation as specified. The door shall be tested in accordance to BS EN ISO 104 or equivalent standards at the manufacturer's works, if requested by the S.O. and a copy of the test certificate showing the test results shall be submitted. The door shall be tested on site after installation. Testing shall be made with octave bands of random noise which must show that the insertion loss of the door is equal to or greater than the following values.
Octave Band Centre Frequency (Hz)
125
250
500
1k
2k
4k
Door "insertion loss" (dB)
30
30
34
40
48
48
The doors shall be installed strictly in accordance to the manufacturer's instruction. The doors shall be provided with locks and each lock shall be supplied with three keys.
9.5
External and Internal Finish
9.5.1 Suspended Ceilings Suspended ceiling shall be made of material as listed below or other material as approved by the S.O.
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a)
Mineral fibre board ceilings
Unless otherwise specified, the tiles shall be 18mm thick “Armstrong Second Look II” mineral fibre boards or approved equivalent, and shall be painted to the approval of the S.O. The Contractor shall submit a sample to the S.O. for approval prior to installation. The tiles shall be suitable for use in the local climatic conditions and shall be resistant to attack by termites, pests or fungal growth. b)
Aluminium strip ceilings
The aluminium strip ceilings shall be “Luxalon” aluminium lineal ceilings (without insulation) or approved equivalent in colour to be selected by the S.O. The ceilings shall be installed in accordance to the manufacturer's instructions. c)
Asbestos free fibre cement ceiling boards
The ceilings shall be “UAC-UCO Superflex” or “UAC Decoceal” free ceiling sheets or other approved equivalent. The ceiling sheets shall be 4.5 mm thick in 610 x 1220 mm panel sizes in patterns to be selected and approved by the S.O. d)
Sound absorbent ceilings
The ceilings shall be 'Dampa' 300T 300 mm wide perforated aluminium sound absorbent ceilings or equivalent. The units shall be in long lengths to minimise jointing. The surface shall be stoved enamelled with sound absorbent textile and perforated with 1 mm holes at 2 mm centres achieving an open area of minimum 22%. The whole ceiling shall be suspended by galvanised steel hangers, adjustment clips, carriers and splices complete with edge trims and sufficient number of access hatches, all to manufacturer's specification. e)
Suspension system
All framework and accessories for supporting the ceiling shall be aluminium. The sizes of individual members of the system of support shall be such that on completion of the ceiling the deflection at any point shall not exceed 4mm. The Contractor shall submit details of the proposed panel layout and of the supporting system to the S.O. for approval before commencing work. The suspension system shall be fully concealed proprietary brand and shall comprise hangers (with threaded adjustment), cold formed primary crossrails, spline rails and sliding locks. The whole shall carry twice the in-service dead loads without failure or deformations beyond the tolerances stated below:Ceiling departure from nominal plane Change in level of adjacent hangers at more than 1200mm centres Variation from straight by a grid member between adjacent hangers Individual hangers shall carry a load of 200kg without failure. f)
+ 3mm + 1.5mm 0.001 of span
Workmanship
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Ceiling grids in place shall be set out accurately parallel to building grid. In every room tiles shall be set out symmetrically in both directions with or without margin at periphery of 1/2 tile or greater as directed by the S.O. The ceiling shall be installed strictly in accordance with the manufacturer's fixing instructions. Opening, etc in ceiling, if required, shall be trimmed to receive recessed light fittings and neatly cored for vent pipes to exact size. The ceiling grid shall be erected to the heights shown on the Drawings and to a true and level plane. Each board shall be rectangular in shape, measuring 600mm x 1200mm and a minimum of 4.5 mm thick. Except where otherwise approved by the S.O., the panels in any one room shall be of uniform size and arranged in an orderly and symmetrical pattern. Where this is not possible, they shall be neatly cut and edging strips shall be provided where necessary.
9.5.2 Finishes to Brickwork a)
Plastering
Plastering shall consist of two coats; with total thickness 20mm thick. The undercoat shall be 12mm thick, roughened adequately to form a key for the final coat. The finished coat shall be trowelled with proper metal floats to an even and smooth surface. All arises shall be slightly rounded to 3mm radius. The mortar for plastering shall be gauged in the proportion of one (1) part of cement to one (1) part of lime and three (3) parts of sand. No materials which have started to set or have been affected by damp or long storage shall be used. All materials shall be proportioned by volume using gauge boxes. b)
Rendering
Cement mortar rendering shall consist of two coats; the undercoat shall be 12 mm thick (should not exceed 16 mm or be less than 10 mm). The undercoat of cement mortar shall be thrown and smoothed with a wooden float with as little working as possible. Immediately after the initial set has taken place the surface shall be scored to form a key for the final coat and shall be allowed to dry out for as long as possible. It shall directed by the S.O. be sprayed with water before applying the final coat. The finishing coat shall be worked with a proper wooden float, and the face left with an even and smooth surface. The finishing coat shall be applied onto the undercoat after a minimum lapse of 24 hours and in no case shall the lapse exceed three (3) days. Its thickness shall not exceed l0 mm or be less than 6mm. The finished rendering shall be cured for at least four (4) times a day and kept damp for a period of at least fourteen (14) days after completion. The mortar for rendering shall be gauged in the proportion of one (1) part of cement to three (3) parts of sand.
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9.5.3 Ceramic and Glass Mosaic External tiles of buildings shall generally be of matt glazed ceramic tiles of approved manufacturer, sized approximately 100 x 48 x 8 mm unless otherwise specified. External glass mosaic wall tiles shall be of approved imported Italian vitreous glass mosaics, Group I series, sized 25 x 25 x 4.5mm unless otherwise specified. Internal ceramic wall tiles to areas indicated in Architectural Drawings shall be 200 x 200 x 8 mm fully glazed ceramic tiles or approved equivalent laid to selected patterns and colours shall be as approved by the S.O. Purpose made internal and external angle tiles shall be used as required. Tiling shall be set out in an uniform and symmetrical manner. Small make-up pieces should generally be avoided and for margins, half tile or wider is preferred. Tiles shall be laid to previous rendered surfaces with full bed of water resistant tile adhesive as recommended by the manufacturer. Tiles shall not be fixed until surfaces are thoroughly cured and completely dry. After fixing joints shall be pointed flush with Parian cement. Concrete benches where shown shall be tiled with 200 x 200 x 8 mm glazed ceramic tiles as approved by S.O.
9.5.4 Glazed Wall Tiling Glazed wall tiling shall be in accordance with BS 1281. The tiles shall be l00 mm x l00 mm, true to shape and free from all blemishes. They shall be set and pointed in Pariah cement or set in approved tile adhesive and pointed in Pariah cement. The glazed tiles shall be of tinged blue or white colour as ordered and uniform in size and colour. The pattern and colour of the glazed tiles shall be approved by S.O. prior to order. The glazed tiles shall be arranged in a uniformly symmetrical manner. Joints to tiling shall be exactly in line. External and internal angles shall be radiused and to the dimension shown in BS 1281.
9.5.5 Acrylic Spray Tile and Coating Acrylic spray tile shall be “SKK Acrylic Enamel CT-Tile” system or other approved equivalent by the S.O. The water based ‘granite like’ acrylic coating is to be SKK Eleganstone Spray Granite Coating or equivalent as approved by S.O. The system shall have one coat acrylic sealer, one coat texture compound and two coats acrylic top coats. The acrylic spray tile system shall be carried on 20 mm rendering work. The surfaces to be coated shall be clean, dry, smooth, free from defects, cracks and other imperfection prior to application and damaged area should be repaired before hand. Surfaces to be coated shall be cured for 28 days before commencement of work. Methods of application shall be in accordance with manufacturer's specification. The works shall strictly be applied by the manufacturer or their approved sub- contractors strictly according to their specifications. The Contractor shall provide a guarantee for a period of five years (commencing from the end of Defects Liability Period) against peeling, flaking, discolouration, loss of gloss retention, fungus growth, etc. due to defective material or faulty workmanship.
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9.5.6 Sound Absorbent Wall Lining The wall lining shall be 'Dampa' 300T 300 mm perforated aluminium absorbent wall lining or equivalent as approved by S.O. The specification shall be as Clause 9.5.1 (d) except that the wall lining shall be spaced 100 mm from the wall with galvanised steel spacers and that the sound absorbent units shall have galvanised steel carriers at 300 mm centres up to window sill height.
9.5.7 Floor Finishes - General Floor finishes shall not be laid prior to completion of plastering and wall tiling. Where pipes are brought through floors, the floor finish shall be neatly finished level around metal sleeves and shall not be finished against the pipes. Where necessary to grade finished surface to fall, screed thickness may be adjusted with approval from S.O.
9.5.8 Preparation of Applied Finishes Concrete surfaces specified to be finished with granolithic, ceramic tiles, or other applied finishes, shall be thoroughly roughened, brushed with wire brushes to expose a fresh surface and swept clean, washed with clean water until well soaked. A thin layer of stiff cement grout shall then be well brushed into the roughened surface a few minutes to ensure that it penetrates all the small holes and crevices before laying the applied finish.
9.5.9 Marble Slabs Marble slabs shall be 600 x 600 x 20 mm imported or local marble as specified. Where imported marble slabs are used, they shall be Italian marble or equivalent. Marble slabs shall be selected by the S.O. and laid to approved pattern including boarder. The marble slab shall be protected against weather or damage and staining by other trades. Particular care must be taken against staining from timber, oil, washing from steel work or scaffolding and other injurious substances.
9.5.10 Carpet Tiles Carpet tiles shall be `Versa-Tile' Barklay square carpet tiles or other approved equivalent, unless otherwise specified. The colour and pattern shall be selected by the S.O.
9.5.11 Raised Modular Floor Raised modular floor shall be `Atlas Air' raised modular floor or approved equivalent complete with all accessories such as cable outlets, skirting boards, PVC fascias, panel lifters etc. Panels shall be 600 x 600mm high density processed timber of 33mm thickness sandwiched between 2 sheets of equal thickness plastic laminates. The sub-structure shall consist of an assembly of rust free load bearing components capable of providing a support frame work for the floor panels.
9.5.12 Ceramic Tiles Ceramic floor tiles shall be 300 x 300 x 8 mm or 200 x 200 x 8 mm floor tiles by approved Manufacturer or approved equivalent.
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9.5.13 Homogeneous Tiles General Homogeneous tiles shall be laid absolutely level and set out with the joints maintained in a regular and continuous manner to the satisfaction of the S.O. All tiles shall be bedded, jointed and pointed in matching coloured cement and sand mortar. Floor tiles Floor tiles shall be 300x 300 x 8 mm approved special colours or standard colours heavy duty non-slip homogeneous tiles, laid to selected patterns and matt colours as approved by the S.O. Wall tiles Wall tiles shall be 200 x 200 x 8 mm approved special colours polished porcelain homogeneous tiles laid to selected patterns and colours as approved by the S.O.
9.5.14 Granolithic Finish Granolithic concrete shall consist of two (2) parts of cement to five (5) parts of granite by volume. The granite shall be graded in accordance with Table 3 of BS 1201 for all-in aggregate. The mixing shall be as specified for concrete, and the water content shall be just sufficient to produce a dense concrete of adequate workability. Before laying, the base concrete shall be cleaned and prepared as specified in Clause 9.5.7, a thin layer of stiff cement grout shall then be well brushed into the roughened surface a few minutes before the granolithic concrete is laid. The granolithic shall be spread, screeded to allow compaction, thoroughly consolidated by tamping and floated by means of a steel trowel, screeded again if necessary, to produce an even surface true to within plus or minus 0.80mm of a true plane measured in any direction. The granolithic finish shall be laid to a thickness of 40mm in panels not exceeding 2.5 metres square and to fall where directed to an even graded surface. All panels shall be cast against permanent aluminium strips of 2 mm thick or using approved ebonite strips. The arrangement of panels shall be symmetrical wherever possible and as directed by the S.O. The concrete shall be compacted using wooden straight edges and levelled by very light trowelling. It shall then be allowed to stand until it is hard enough to withstand a final hand trowelling, in the course of which any laitence collecting on the trowel shall be removed and not trowelled back. As soon as the granolithic surface has hardened sufficiently to withstand defacement, it shall be kept continuously damp for a period of not less than ten (10) days. The surfaces shall not be exposed to traffic or be worked on during this period.
9.5.15 Pebble Washed Finish Aggregate shall be of 2mm - 3mm rounded river gravel not produced by crushing, 100% stone and free of shell grit, dirt, organic material and other matters. Aggregate colour is to be true and not obtained by colour treatment such as bleaching and dying. Samples shall be submitted to the S.O. for approval prior to ordering. Trial finishes are to be prepared for the S.O.’s approval prior to fabrication of in-situ paving.
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A ‘Barra Emulsion 57’ or other equal and approved bonding agent must be applied to the pebble washed finish and to ensure a good bonding between aggregate and screed. The Contractor shall submit shop drawing based on the design drawing for the S.O.’s approval prior to the commencement of works.
9.5.16 Quarry Floor Tiles Quarry tiles shall generally conform to the requirements of BS 1286. Quarry tiles shall be supplied and installed where specified or indicated on the Drawings. The tiles shall be of the size, quality, patterns and colours described or shown in the Drawings as approved by the S.O. The quarry tiles shall be 6.5 mm minimum thickness homogeneous type which is obtained from an approved source. The tiles shall be laid to approved patterns and bedded and Before laying, the quarry tiles shall be well wetted and then laid on a l9mm thick 1:3 cement and sand screed that has been thoroughly worked into the roughened and cleaned concrete surface. The quarry tiles shall be pointed in a matching or contrasting cement colour to be selected by the S.O. Quarry tiles with one edge rounded shall be placed to form a skirting of a single course height. After laying, the tiled floor shall be pointed and grouted with tinted cement to match and to be scrubbed with water to remove slurry, dirt, stains, etc. and polished to desired surface finish. After final polishing, the whole floor is to be washed with hot water and soap waxed strictly in accordance to the manufacturer’s instructions. All damaged, defective stained or discoloured floor tiles shall be rejected and replaced by the Contractor at his own expense.
9.5.17 Concrete Floor Hardener Concrete floor hardener shall be applied on the flooring at the appropriate buildings as specified and detailed in the drawings. Typical areas of use include sludge storage building and pumping station. Approved type shall be used to suit the required function. Concrete floor hardener shall comply with BS 476, Part 7: 1987. Where a coloured flooring is required, site trial shall be carried out to assess possible local variations caused by aggregates and sands used in the base concrete. Timing of the concrete floor hardener is important, hence care shall be taken to ensure adequate labour, machinery and material is available to complete the whole area while sufficient moisture is available to fully react to provide a good dense finish. Concrete floor hardener shall not be applied at temperatures below 10oC or where ambient relative humidity exceeds 80% when tested in accordance with BS 8203 Appendix A or by visual thermohygrometer. The most important objective for the application of the concrete surface hardener is to achieve a functional and reliable coating system to withstand the vehicular loading, heavy equipment and the day-to-day operation. Concrete surface hardener material shall be deep penetrating to the concrete surface to provide long-term protection against wear. The concrete surface shall be thoroughly prepared, clean and free from dusts, woods and other foreign substances before concrete hardener is applied in order to achieve maximum adhesion between the surface hardener and substrate. Oil and grease penetration shall be removed by hot compressed air. Any surface irregularities may show through causing excessive wear on high spots and changing the perceived colour of the surface hardener. Sanitary sewage is not highly corrosive, but under anaerobic conditions, bacteria may decompose sanitary sewage and form hydrogen sulphide gas. This gas combines with water or moist air to form sulfuric acid which may attack the concrete surfaces. The concrete surface hardener shall provide high
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performance and high resistance to this condition. It shall be able to provide water repellence, abrasion resistance, dust proof easily cleaned surface which is resistant to oils and liquids, feature easy and quick application and form an impervious finish easily cleaned surface for low maintenance. Samples of concrete surface hardener proposed to be used shall be submitted to the S.O. for approval prior to application. The concrete surface hardener shall be applied by specialist applicators or trained and certified personnel approved by the S.O.
9.5.18 Mosaic Tiling Mosaic tiles shall be 25 or 20 mm square non-slip ceramic mosaic. The pattern and colour of the mosaic tiles shall be approved by the S.O. before making the order. The squares shall be uniform in size and colour and shall be held in position in panels by being gummed onto a piece of paper for transport to site. The base concrete surface for receiving the mosaic tiles shall be prepared as specified in Section 9.5.7 and 9.5.8. The panels of mosaic shall then be bedded into a layer of 25mm thick mortar consisting of 1 part cement and 3 parts sand and shall be hand tamped with wooden blocks. As soon as gummed paper is removed by damping the surface with water before the mortar sets, the groove between the mosaic tiles shall be adjusted and straightened with straight metal plates. Any excessive mortar on the surface area shall be cleaned with a piece of clean wet cloth. The mosaic tiles shall be arranged in an orderly symmetrical manner. The mosaic tiling to floors shall be kept damp for a period of three (3) days after laying and during this period, the flooring shall not be used for any traffic. Mosaic tiling shall be measured by the nett surface area actually laid. The rate shall be deemed to include for the cost of supply and laying mosaic tiles, preparation of floor, walls and columns, supply and placing of 25mm thick mortar bedding, forming to channel, openings, pipes, chamfers, tamping and proper cleaning of the surfaces before handing over. Separate measurement will be made for skirting to plinths, walls and columns.
9.5.19 Terrazzo Tiling Terrazzo tile shall be not less than 300mm square and 10 mm thick. The pattern and colour of the tiles shall be approved by the S.O. before making the order. The base concrete surface for receiving the terrazzo tiles shall be prepared as specified in Clauses 9.5.6 and 9.5.7. Terrazzo tile shall be bedded into a layer of 25mm thick mortar, consisting of 1 part cement and 3 parts sand.
The tiles shall be hand tamped with wooden blocks to level and any differences in the thickness of the tiles shall be made up by the wet mortar bedding. The tiles shall be arranged in an orderly manner such that joints formed between tiles are in a straight line. The grooves shall be kept as thin as possible. Terrazzo tiling shall be measured by the nett surface area actually laid. The rate shall be deemed to include the cost of supply and laying of the tiles, preparation of floor, supply and placing of 25 mm thick mortar bedding, forming around services, polishing and washing before handing over.
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9.5.20 Vinyl Tiles Vinyl asbestos tiles shall be supplied and installed where specified and/or shown on the drawings and shall be of a pattern and colour approved by the S.O. The tiles shall be bedded on an adhesive to be supplied by the manufacturer and shall be installed in strict compliance with the manufacturer's instructions.
9.5.21 Slate Slate tiling shall be executed by specialist and the Contractor shall be fully responsible for these works and any defective materials and/or faulty workmanship will not be accepted and shall be made good and/or re-executed entirely at Contractor’s own expense. The slate shall be 10mm thick or large irregular shape and size, bedded in cement and sand (1:3) and pointed in cement with uniform joints of 13mm width in approved colour to match slate. The slate shall be properly sealed with an approved sealant on all surfaces. Samples shall be submitted to the S.O. for approval prior to ordering.
9.5.22 Skirting All floor finishes shall have 100mm skirtings of the same material on walls vertical to the floor concerned.
9.6
Roofing
9.6.1 Roof Waterproofing All concrete surfaces to receive waterproofing, whether flexible sheet materials and brush or sprayapplied coatings shall be finished smooth preferably to wood float finish. Surface to be dry and clean, free from oil, and swept to remove dust and loose stones. Ensure that all pipe or pipe sleeves are formed and ready for waterproofing. All surface must be primed before applying the waterproofing membrane. Apply primers and full coats by brush unless otherwise specified. Concrete roofs shall be waterproofed by waterproof membranes protected by 1200mm x 1200mm x 50mm cement and sand protective panels reinforced with BMC A98. The membrane shall be turned up at the kerbs and parapets and turned into a sealing chase and pointed with sealant or mastic. Membrane collars, sleeves, etc. should be provided and properly seal at areas where pipes, conduits, etc are found, ensuring water tightness to manufacturer’s details. Sheet and liquid membranes shall be protected until covered by subsequent construction or handing over. The Contractor shall submit a proprietary waterproofing system including description and details for approval by the S.O. taking into consideration the mechanical strength, watertightness, fatigue resistance and its suitability under local climatic conditions. Application shall be carried out by approved specialist applicators, strictly in accordance with the manufacturer’s specifications. The Contractor shall, jointly with the manufacturer, provide a minimum 10 year guarantee of the proprietary waterproof system against leakage due to faulty material and workmanship.
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9.6.2 Roof Insulation Material Roof insulation shall be installed between the concrete roof tiles and soffit of the building where specified. The roof insulation material shall be 50 mm thick fibreglass overlain with a composite insulating material made up of 2 layers of aluminium foil/polymeric adhesive/2 layers of Kraft paper laminate bonded together with a flame retardant adhesive and reinforced with a special polypropylene fabric. The roof insulation shall be laid strictly in accordance with the manufacturer’s specifications and over one layer of 50 mm thick fibreglass insulation. It shall have a thermal conductivity of 0.032 – 0.035 Kcal/mh degree contrigrade at normal room temperature. Insulation quit shall be laid over galvanised chicken wire mesh, unless otherwise specified. It must also be protected from exposure to rain whilst laying. Sheets of the materials shall be sealed together with pressure sensitive foil tape to form a moisture free protective barrier. The fire rating of the insulation shall comply with the following: Flammability test to AS 1530 Part 2 Spread Factor 0 Speed Factor 0 Heat Factor 1 Flammability Index* 1 *Note: Shall comply with BS 476 Part 6 – 1989 Fire Tests on Building Materials and Structures Method of test for fire propagation for product, and BS 476 Part 7: Fire Tests on Building Materials and Structures – Method of Test to determine the classification of the surface spread of flame of product.
9.6.3 Metal Roof Decking and Roofing Sheets Metal roof decking
i)
Metal roof decking shall be the proprietary specialist system described or shown on the Drawings, and shall generally be coated corrugated steel sheets, free from twist, buckle or other surface imperfections. Galvanising shall be clean and free of obvious surface contamination and defects. The Contractor shall provide complete details of the type, section, sizes, gauge, thicknesses, etc. of the roof decking, including fixing method.
ii)
Fascias shall be constructed using similar materials.
iii)
Metal roof decking shall be laid such that ribs run parallel to roof framing members, and at 90 degree to purlins. Roof sheets shall be securely fixed by straps, and completely watertight. No puncturing of the deck would be permitted. Lapping shall be as per manufacturer’s instructions.
iv)
Galvanised self-drilling screws complete with neoprene washers shall be used in fastening cladding to steel purlins, girts and other supports. Holes for fasteners shall be drilled accurately on the centreline of the corrugation directly over the supporting
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purlin or girt. Cladding with wrongly positioned holes shall be rejected; no repair of such holes with bitumastic or other sealant shall be permitted. v)
Suitable ridge capping, side flashing and side capping pieces of the type and size recommended by the manufacturer shall be supplied and fixed at locations shown on the Drawings.
vi)
Cladding for roof shall be supplied with suitable preformed roof connectors. Ridge ends shall be fitted with suitable end closers and lined with bitiumastic seal.
Roofing sheets The roofing sheets shall be a minimum of 0.60mm thick galvanised steel with approved protective coating of silvery-matt appearance. Steel base shall be a minimum of 0.55mm thick with minimum yield stress of 300MPa. The roof shall be supplied complete with acoustic insulation where specified on the Drawings. The roof shall be laid to fall as shown on the Drawings and shall be secured to zinc coated or painted steel purlins in accordance with the manufacturer's instructions without the need of puncturing holes through the roofing sheets. Roof decks shall be of the profile specified on the Drawings and shall be in continuous lengths without end joints wherever possible. However, where end joints are necessary they shall be made to detail conforming with the manufacturer's recommendation.
9.6.4 Interlocking Concrete Roof Tiles i)
Interlocking concrete roof tiles shall be of approved type and colour and conforming to the requirements of BS EN 14437.
ii)
All tiles shall be equal to the samples approved by the S.O. and shall be of a uniform colour. All broken, chipped or defective tiles shall be immediately removed off the site and replaced with sound tiles.
iii)
Tiles shall be laid to the pitch indicated on the Drawings on suitably sized tanalised timber battens to details as described or shown on the Drawings. Roof tiles shall be laid to “broken joints” and to a maximum gauge recommended by the tile manufacturer. Each course shall be laid so that the tiles are properly set out to suit the slopes.
iv)
Each tile in every alternative course shall be nailed by galvanised iron nails. In addition, each eaves tiles and tiles adjacent to hips, valleys and ridges shall be nailed. All laying including lap length and fixing shall be carried out strictly in accordance with manufacturer’s instruction and recommendation.
v)
Eaves shall overhang fascia by minimum 50 mm.
vi)
Form cement mortar (1:3) fillet along the full length of verges.
vii)
Ridges and hips shall be formed by half round ridge tiles and 1/3 round hip tiles.
viii)
Ridges and hips shall be bedded with cement and sand (1:3) mortar at the edges neatly pointed with tinted cement mortar to match general tilling. End ridge tiles shall be stopped by standard ridge end tile. Barge tile shall be stopped by using standard barge tile end.
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Section 9 - Building Works
ix)
Execute all necessary cutting and fitting at abutments and top edges.
9.6.5 Asbestos Cement Roofing Sheets i)
Corrugated asbestos cement roofing sheets shall be of the sizes, colour and patterns described, and of approved quality and weight, free from flaws, broken edges, etc.
ii)
The sheets are to be laid with end laps of minimum 225 mm and 38 mm corrugations side laps, or as required for the specific type of roofing sheet.
iii)
The sheets shall be fixed with galvanised steel drive screws to timber purlins and properly secured.
iv)
All cuttings, whether straight, raking or circular on roofing sheets shall be properly and neatly cut with a hand saw.
9.6.6 Roof Fascia Roof fascia shall be 0.46mm thick with approved protective coating of coloured appearance. The profile of the fascia and the installation shall be as shown on the Drawings.
9.6.7 Roof Drainage a)
Galvanised Mild Steel Gutters, flashings and Cappings:
i)
The galvanised mild steel flashings and Cappings shall be of gauge indicated and shall generally comply as regard manufacture to the requirements of BS EN 10143.
ii)
Provide 22 gauge galvanised mild steel gutters with soldered seams and joints and fixed to plywood lining, timber battens or with concealed galvanised mild steel straps.
b)
Rain water down pipe:
UPVC rain water down pipes and fittings shall be obtained from an approved manufacturer. They shall be formed into required lengths where necessary by an approved method recommended by the suppliers. Steel rain water pipes and fittings shall be of hot dipped galvanised 1.25 mm pressed steel sheets and rectangular in cross section. They shall be formed into required lengths by an approved method of soldering and properly secured with 50 mm x 0.8 mm galvanised sheet iron straps spaced at approximately 1800 mm centre.
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After erection, all exposed surfaces shall be cleaned down with lithoform and painted with one flat undercoat and two high gloss finishing coats of paint of approved quality.
9.7
Glazing
9.7.1 Glazing and Fixing Glass All glass and glazing shall comply strictly with BS 952 and shall be undertaken by an approved supplier. Unless otherwise specified, tinted float glass of 6mm thickness shall be used. Glass shall be free from bubbles, scratches and other defects. Glass shall be accurately cut to fit rebates and carefully bedded, back puttied, sprigged or pinned (beaded where specified) and evenly trimmed with all splayed edges straight and smooth. Defective, cracked or damaged glass shall be replaced. Glass fixed to internal windows shall be held in place by suitable wood beads and soft packing. The packing shall be wash leather or felt of approved quality. Glass of the control rooms of the Control Buildings shall be of approved anti-glare quality or with solar control tinting. All glass louvres shall be of minimum 230mm width to prevent easy breakage. Putty for glazing shall conform to BS 544. For wooden rebates it shall be Type 1 linseed oil putty. For metal rebates it shall be Type 2 gold size putty or an approved proprietary make. Glass panes shall be cut to allow a margin of 3mm to 6mm all round between the glass and the rebate. Back puttying shall be carried out and pegs, clips or springs shall be inserted as required. The front putty shall be applied neatly and evenly and shall be carefully bevelled off to a smooth level surface suitable for painting. Immediately before completion of the Contract all glass shall be cleaned both inside and outside and all defective, cracked or damaged panes shall be replaced without extra charge.
9.7.2 Frameless Glass Provide and fix 12 mm thick tinted frameless float glass where indicated in the Architectural Drawings. All joints between adjoining glass panels, and between glass panels and masonry work shall be sealed with watertight structural sealant to the approval of the S.O. Prior to the installation of the frameless glass panels, shop drawings indicating clearly the detailed fixing of the glass panels shall be submitted to the S.O. for approval.
9.7.3 Mirrors Mirror glass shall be of silvering quality 6mm thick float glass having a layer of silver and a layer of copper deposited on the back, and covered with a protective paint coating. Mirrors shall be fixed to masonry walls with waterproof plywood backing & dome headed screws complete with 12mm natural anodised aluminium trimmings all round.
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Section 9 - Building Works
The size of mirrors shall be 600 x 300 mm for individual hand basins (without vanity slabs) and 750 mm high across the full width of vanity slab where hand basins are set into them.
9.7.4 Cleaning and Replacement Immediately before handing over, all glass and mirrors shall be cleaned, polished and replaced if damaged or broken. During the progress of the work, the glass shall be kept clean by prompt removal or foreign matter, particularly cement products. Glass shall be cleaned with clean water with or without detergents added to it. Glass cleaning agents such as paraffin (kerosene), acid or abrasive cleaners which contain felspar shall not be used for glass cleaning. Hard objects which may result in cuts, scratches or marks on the surface of the glass shall not be used for removing cement, paint or labels. Glass and mirrors with cuts, scratches or marks on their surfaces shall be replaced without extra cost.
9.8
Sanitary Plumbing
9.8.1 General All soil, waste and vent pipes and sanitary plumbing fittings shall be uPVC as specified on the Drawings. Generally uPVC pipes shall be used within buildings and under floors of buildings and clay or pitch fibre pipes shall be used outside buildings. All pipes whether shown on Drawings, specified or required shall be installed and concealed in an approved manner to meet structural and architectural conditions and as far as possible to avoid interference with work of other trades. Care shall be taken in arranging the exposed pipework to appear neat and in true alignment. All pipes and fittings shall be thoroughly cleaned before installation. Any scale, burrs, fins and obstructions shall be removed. Unless indicated on the Drawings or approved by the S.O., all soil, waste and vent pipes shall not be extended on the external face of any wall of any building. When indicated on the Drawings or approved by the S.O., all pipes on the external face of the buildings shall be extended vertically. All connections to soil, waste and vent pipes shall be made with approved forty five (45) degree junctions.
9.8.2 Fixture Outlet The Contractor shall fix to the outlets of all sanitary fixtures the necessary soil pipes, trap and waste pipes, soil and anti-syphonage vent pipes. All pipes shall be extended, clipped and supported in accordance with this Specification and Local By-Laws requirements to connect the soil and waste pipes to drain and to extend vent pipes to open air. Soil pipes, waste pipes and vent pipes shall be of the type and size indicated on the Drawings or as required. Traps shall be of loose ring `P' trap type.
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Soil and anti-syphonage vent pipes shall be completed with cowl and clips, and extended to requisite heights as required. Unless otherwise indicated on Drawings or approved by the S.O., all vent pipes shall be extended vertically.
9.8.3 Jointing and Supporting Pipes Wherever possible, the number of joints in the pipework shall be kept to a minimum and joints shall be made only at the supports. Pipe cut-offs shall not be used to fabricate lengths of pipe. All piping shall be supported at maximum interval of 1800mm by approved pipe clips, and/or hangers securely fixed to walls, floors and members of building construction to the satisfaction of the S.O.
9.8.4 Sanitary Fixtures All sanitary fixtures shall be fixed in the positions shown on the Drawings in accordance with the description, type, and dimensions, complete with all necessary accessories. The fittings and accessories shall comply with the relevant British Standard. W.C.s -
Pedestal type shall be “Shanks Armitage” Unisyla pedestal or equivalent approved WCs coloured for Administration & Control Buildings & white for the remaining buildings, with matching cisterns unless otherwise specified.
-
Squatting type shall be white “Shank Armitage” Andria or equivalent approved WCs complete with vitreous china cisterns.
-
Earthernware plain edge sinks shall be “Amitage Shanks” or equivalent approved in white fire clay complete with chrome plated taps.
-
Metal sinks shall be “TML” or equivalent approved stainless steel complete with chrome plated taps.
Toilet Paper Holders
Toilet paper holders shall be “Bobrick” or equivalent approved 150 x 150 mm BS EN 15167 stainless steel paper holders.
Urinals -
Urinals shall be coloured “Armitage Shanks” Santor or approved equivalent with divisions and water cisterns for Administration and Control Buildings unless otherwise specified.
Sinks
Where trough urinals are indicated, they shall be “Diethelm” or equivalent approved stainless steel type or approved equivalent of the dimensions shown with spreaders and concealed flush pipes. Wash
-
Vanity basins shall be coloured “Armitage Shanks” Jade type or equivalent approved for basins Administration and Control Buildings unless otherwise specified. The remaining ones shall be white “Armitage Shanks” Dorex types or equivalent approved.
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Section 9 - Building Works
Taps
-
Pillar taps shall be “Dorf” chrome plated “ArrowLine” type or DE 120 Duo-Mix basin mixer as appropriate or equivalent approved. Laboratory sinks shall be white “Diamond” 355mm square laboratory sinks complete with `Daelim' double faucets or equivalent approved.
Shower -
Showers shall be “Dorf” 90mm chrome plated DE 34A twin ball showers or equivalent approved.
All sanitary fixtures shall be thoroughly cleaned with non-abrasive cleaner on completion.
9.8.5 Testing Sanitary Plumbing Sanitary plumbing soil, waste and vent pipes shall be inspected and tested before concealment. All tests and inspections shall be carried out in the presence of the S.O.
9.8.6 Floor Waste Each floor waste outlet shall be fixed with screwdown chrome-plated drainage gratings. The gratings shall be set flush with the floor to permit proper and free drainage of the surrounding areas.
9.8.7 Sanitary Fittings Sanitary fittings shall comply with one of the following appropriate Standards: BS 1125, BS 1184, BS 1188, BS 1206, BS 1254, BS 1281, BS EN 997, BS EN 33, BS EN 37. Sitting type W.C.'s shall have a wash down W.C. pedestal with "S" trap in one piece, a plastic seat and cover, "low level" flushing cistern of 13.5 litres capacity and lever flushing handle. Squatting type W.C.'s shall have a wash down W.C.'s trough with "S" trap in one piece, high level flushing cistern of 9 litres capacity and flushing chain. The cistern shall have a 12mm ball valve with silencer, a plastic ball and a l9mm diameter overflow pipe. W.C.'s shall be supplied complete with downpipes, all necessary fittings, and l9mm diameter overflow pipes discharging outside the building. Internal plumbing for sanitary fittings shall be uPVC. It shall be noted that locally manufactured sanitary fittings are to be used where possible. No substitution shall be allowed without the prior approval of the S.O.
9.9
Cold Water Plumbing
9.9.1 General The service water supply shall be drawn from the service storage tanks. Pipes and fittings shall be of copper pipes conforming to BS 1387. Copper pipes shall be painted as specified or ordered by the S.O.
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All pipes and fittings shall be thoroughly cleaned before installation and any burrs, fins, etc., shall be removed. Where piping is installed above ground, it shall be securely fixed to walls and within roof spaces, wall cavities, ducts, etc. at maximum intervals of 1800mm and at joints and changes of direction. Pipes shall be laid to straight lines and uniform grades without sags. Pipes shall be secured with galvanised steel clips and screws and/or approved pipe hangers. Any pipe found to be "noisy" during testing due to insufficient support or loose fixing will be rejected. Where possible, piping shall be concealed in wall ducts and partitions and not be exposed on internal or external faces of walls.
9.9.2 Isolating Valves Where an isolating valve is installed inside a building it shall be placed in an accessible position. Where access to valves is required through duct walls, in cavities, etc, an opening of suitable size shall be provided in the wall and covered with a stainless steel plate, fixed with stainless steel screws to enable easy removal.
9.9.3 Installation of Taps and Outlets All taps and outlets shall be fixed with wall anchors, lugged tees, elbows, breeching pieces, etc, all to the satisfaction of the S.O. Taps to be installed shall be to BS 1010.
9.9.4 Ironmongery The ironmongery shall be of the type as proposed in Schedule of Particulars which shall be of an approved make. If the tender is accepted, the Contractor shall supply and fix the type of ironmongery as stated in the Schedule. No substitution shall be allowed without the prior approval of the S.O.
9.10 Hard core 9.10.1 Material and Laying When shown and required, approved hard core consisting of good, sound, broken bricks or stones shall be provided and laid to the thickness shown on the drawings, well rammed, compacted and blinded with sand. All hard core shall be well watered immediately prior to the depositing of concrete thereon.
9.11 Building Acoustic Treatment a)
General
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Description Furnish all plant, labour, equipment, appliances and materials and performing all operations in connection with Building Acoustic Treatment. Submittals Manufacturer’s specifications and installation instructions shall be provided for the type of acoustic treatment. 600 x 600 mm square samples of the type of insulation shall be provided. Delivery, Storage and Handling Insulation materials shall be delivered in the manufacturer’s unopened containers or packages, fully identified with trade name, type, class and other identifying information. Delivery shall be sequenced to avoid project delays and to permit proper co-ordination of the work. Acoustic materials shall be stored above grade and protected from weather and damage from any source. The building acoustic treatment shall not become wet or soiled and the Contractor shall comply with other precautions and recommendations of the manufacturer to protect insulation from deterioration. b)
Products
Insulation Rigid plastic insulation, which shall be 50 mm thick on walls and 70 mm on roofs, shall be extruded rigid closed-cell plystyrene foam board with ship-lapped edges having the following properties Property Density Five-year aged average Thermal conductivity When tested at 24oC Compressive strength (av) Water Absorption (av) Water vapour permeability (av)
Typical Results 35 kg/m3
Test Method
0.032 W/m.k
ASTM C 518 or DIN 52612
280 kPa 1% 0.79 perm.cm
ASTMD 1621 or DIN 53421 ASTM D2842 ASTM C355
Where required for fire rated construction rigid polyester impregnated fibre glass insulation with noncombustible fabric covering shall be provided. It shall comply with FS HH-1-521E, type 1, and be of the thickness, density and type tested and approved for the required ratings. Expanded polystyrene insulation which is not manufactured with, or contains chlorofluorocarbons (CFC’s) which are known have harmful effects on earth’s ozone layer and the environment, shall be used. Adhesives that are compatible with the insulation, protection course and substrata materials shall be used. For securing fire rated insulation to the ceiling, galvanised steel clamps of suitable size and strength shall be provided to suit the installation.
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Section 10 - Roadworks
10.0
ROADWORKS ...........................................................................................10-1 10.1
Preparation of Formation to Receive Road Pavement ...............10-1
10.2
Earth Subgrade ..............................................................................10-1
10.3
Subgrade of Rock ..........................................................................10-1
10.4
Pavement Thickness .....................................................................10-2
10.5
Geotextile Filter Membrane...........................................................10-2
10.6
Storage of Geotextile Filter Membrane ........................................10-3
10.7
Laying and Spreading Over the Geotextile Filter Membrane .....10-3
10.8
Sub-Base ........................................................................................10-3
10.9
10.8.1
Sub-base Materials .........................................................10-3
10.8.2
Alternative Sub-base ......................................................10-4
10.8.3
Laying and Compaction of Sub-base ............................10-5
Road Base ......................................................................................10-5 10.9.1
Road Base Materials .......................................................10-5
10.9.2
Laying and Compaction of Roadbase ...........................10-6
10.9.3
Finished Surface .............................................................10-7
10.9.4
Definition and Requirements Associated with Table 10.1 ...10-8
10.10 Bituminous Material ......................................................................10-8 10.10.1 General.............................................................................10-8 10.10.2 Cutback Bitumen.............................................................10-8 10.10.3 Bitumen Emulsion...........................................................10-9 10.10.4 Storage, Handling and Heating-of Bitumen ..................10-9 10.10.5 Depot Tray Test ...............................................................10-9 10.11 Bituminous Prime Coat .................................................................10-9 10.11.1 Material ............................................................................10-9 10.11.2 Surface Preparation ........................................................10-9 10.11.3 Application of Prime Coat ............................................10-10 10.11.4 Spraying Procedure ......................................................10-10 10.11.5 Protection of Prime Coat ..............................................10-10 10.12 Asphaltic Concrete ......................................................................10-11 10.12.1 Aggregate, Binder and Composition...........................10-11 10.12.2 Mixing.............................................................................10-12
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Section 10 - Roadworks
10.12.3 Transport .......................................................................10-13 10.12.4 Sampling and Testing...................................................10-13 10.12.5 Asphaltic Concrete Layer Thickness and Tolerance .10-13 10.12.6 Laying of Asphaltic Concrete.......................................10-14 10.12.7 Bituminous Tack Coat ..................................................10-14 10.12.8 Joints .............................................................................10-14 10.12.9 Laying Around Manhole Covers ..................................10-14 10.12.10 Compaction ...................................................................10-14 10.13 Road Shoulders ...........................................................................10-15 10.14 Laterite Surface............................................................................10-15 10.15 Lateral Shoulder Subsoil-drains.................................................10-16 10.16 Refilling of Excavated Pipe Trenches for Roadways................10-16 10.17 Compliance with Specification ...................................................10-16 10.18 Road Markings .............................................................................10-18 10.18.1 Thermoplastic Material .................................................10-18 10.18.2 Preparation of Surface..................................................10-18 10.18.3 Preparation of Thermoplastic Material on Site...........10-18 10.18.4 Laying ............................................................................10-18 10.18.5 Protection of Markings .................................................10-19 10.18.6 Reflectorisation .............................................................10-19 10.18.7 Thickness ......................................................................10-20 10.18.8 Tolerance on Width.......................................................10-20 10.18.9 Defective Materials or Workmanship ..........................10-20 10.18.10 Clearing Up ....................................................................10-20 LIST OF TABLE TABLE A:
CLASS ‘A’ GLASS BEADS : PARTICLE SIZE DISTRIBUTION, ROUNDNESS AND DEFECTS.
TABLE B:
CLASS ‘B’ GLASS BEADS : PARTICLE SIZE DISTRIBUTION, ROUNDNESS AND DEFECTS.
TABLE 10.1 :
PLANT AND METHOD SPECIFICATION FOR COMPACTION OF EARTHWORKS AND SUBGRADES
TABLE 10.2:
COMPACTING PROCEDURE FOR UNBOUND SUB-BASE AND ROADBASE MATERIALS AND FOR SOIL-CEMENT AND CEMENT-BOUND GRANULAR ROADBASE
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Section 10 - Roadworks
10.0 ROADWORKS 10.1
Preparation of Formation to Receive Road Pavement
The preparation of formation shall be carried out only after completion of all sub-grade drainage, piped drains, services and ducts or any other drainage work that might affect the works, unless otherwise approved by the S.O., and such preparation shall be carried out immediately prior to the laying of the sub-base or the road base where no sub-base is required. The surface of the formation shall be substantially uniform in density throughout its entire width and shall conform to the density requirements for compaction. The surfaces in subgrade whether on fill or on cut ground shall be compacted to the requirements for earth subgrade as specified in Section 10.2 It shall be trimmed to conform to the lines, camber, grades and typical cross sections shown on the Drawings, or as directed by the S.O. The surface shall be constructed to sufficient accuracy to permit the construction of subsequent layers of material to the thickness, cross-section surface tolerance and compaction specified but in no case shall a tolerance of + 10mm and -20 mm from the required levels shown on the Drawing be permitted. Where ruts or other objectionable irregularities occur as a result of construction traffic or other causes, the Contractor shall reshape and re-compact the formation to the required density before the sub-base or road base is placed at his own expense.
10.2
Earth Subgrade
Where soft spots and unsuitable material occur, they shall be removed and backfilled with approved suitable material and compacted according to the Specification in Table 10.1, "Plant and Method Specification for Compaction of Earthworks and Subgrades". The material used for subgrade shall have a soaked CBR value, after the specified compaction, as indicated on the Drawings or if not indicated, not less than 5. The formation shall then be checked and the final trimmed surface shall be rolled by one additional pass of a smooth-wheeled roller of not less than 5 tonnes or an equivalent vibratory roller prior to the laying of the sub-base or base-course. Notwithstanding the above the top 300mm of the finished embankment shall be compacted to a dry density equal to at least 95% of the maximum dry density as determined by BS 1377 Compaction Test (4.5 kg rammer method). Other embankment layers more than 300mm below the underside of the lowest layer of sub-base and shoulder shall be compacted to a dry density equal to at least 92% of the maximum dry density as determined by BS 1377 Compaction Test (4.5 kg rammer method). The formation shall be so constructed to drain surface water to the side ditches or other drainage system. If the Contractor allows the moisture content of the completed formation to reach a value above the permitted maximum for the compacted material, the Contractor shall allow the materials to revert to an acceptable moisture content and, if directed by the S.O., make good at his own expense the surface by recompaction before laying the sub-base or road base.
10.3 a)
Subgrade of Rock Where the surface of an excavation in rock extends over the whole width of the formation :-
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i) ii)
the rock surface shall be trimmed to a free draining profile, at or below formation levels. No high spot shall protrude above the formation levels; any voids or depression more than 0.5 metre in depth below the formation level shall be filled up with approved lean concrete having 7 day cube strength greater than 7 N/sq.mm. The rock surface shall then be brought up to the formation levels with approved crushed rock or gravel, regulated and blinded.
b)
Where rock outcrop occurs over part of the formation only, the rock outcrop shall be excavated down to a level not less than 300mm below the formation level. The surface shall then be brought up to a level with suitable subgrade material.
10.4
Pavement Thickness
The thickness of the various layers of the pavement shall be as shown on the Drawings. However before the construction of the pavement the S.O. may carry out or direct the Contractor to carry out soaked California Bearing Ratio (C.B.R.) tests as described in BS 1377 on the prepared subgrade to determine the strength of the subgrade. The S.O. may order variations in the thickness of the various layers of the pavement as shown in the typical cross-section Drawings as a result of the above tests.
10.5
Geotextile Filter Membrane
The geotextile to be used, where specified or shown on the Drawings, for the drainage embankment blanket filters and sub-base/formation interface shall conform to the following specifications :
CRITERIA Maximum force sustained in plain strain
MINIMUM VALUE 8 kN/m (min.)
Maximum force sustained in grab tension with 50% elongation (ASTM 1682 - 200mm strip)
0.69kN (min.)
CBR Puncture Resistance
1.6kN (min.)
Minimum flow through geotextile under 100mm head of water
50 l.p.s./sq metre (min.)
Maximum Pore Size
200 um (max.)
Acid Resistance
pH >= 2 (min.)
Basic (Alkali) Resistance
pH 5.2
16 8
Unsuitable 16
Unsuitable Unsuitable
Wheel load (Tonnes) 4-6 6-8 8-12 > 12
12 12 10 8
Unsuitable Unsuitable 16 12
Unsuitable Unsuitable Unsuitable Unsuitable
Static force per 100mm width (kN) 0.71-1.25 1.26-1.75 1.76-2.3 2.31-2.8 2.81-3.5 3.51-4.2 4.21-4.9
16 6 4 3 3 3 2
Unsuitable 16 6 5 5 4 4
Unsuitable Unsuitable 10 9 8 7 6
Static force under base plate (kN/m2) 13.8-17.2 17.2-20.7 > 20.7
8 5 3
Unsuitable 8 6
Unsuitable Unsuitable 10
Mass (kg) 50-60 65-75 > 75
4 3 2
8 6 4
Unsuitable 10 8
Power rammer on Mass (kg) dropping weight 100-500 compactor > 500
5 5
8 8
Unsuitable 12
Smooth-wheeled roller
Pneumatic- tyred roller
Vibratory roller
Vibrating- plate compactor
Vibro-tamper
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Section 11 - Drainage Works
11.0
DRAINAGE WORKS..................................................................................11-1 11.1
Stone Pitching................................................................................11-1
11.2
Weepholes......................................................................................11-1
11.3
Rip-rap ............................................................................................11-1
11.4
Placing Rip-rap ..............................................................................11-2
11.5
Filter Material .................................................................................11-2
11.6
Material for Underdrains and Rubble Drains...............................11-2
11.7
Filter Fabric ....................................................................................11-3
11.8
Reno Mattresses ............................................................................11-4
11.9
Gabions ..........................................................................................11-4
11.10 Porous Concrete Pipes .................................................................11-4 11.11 Salt Glazed Stoneware Pipes and Fittings...................................11-4 11.12 Reinforced Concrete Pipes ...........................................................11-5 11.13 Clayware Field Drain Pipes and Fittings......................................11-5 11.14 Laying Drain Pipes.........................................................................11-5 11.15 PVC Pipes.......................................................................................11-5 11.16 Drain Pipe Test Certificates ..........................................................11-6 11.17 Drain Covers and Gratings ...........................................................11-6
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Section 11 - Drainage Works
11.0
Drainage Works
During the course of excavations, should the Contractor’s workmen uncover any cables, ducts, pipe mains, etc., work shall be stopped immediately and shall not again be started until the matter has been reported to the S.O., who will issue whatever instructions he deems appropriate. All pipes, ducts, cables, mains and other services exposed during excavations shall be effectively supported and the Contractor shall take all necessary precautions to prevent any damage thereto. All damage shall be made good at the Contractor’s expense. Form all stormwater drainage channels to the type, size, alignment and grade shown on the Drawings.
11.1
Stone Pitching
Stone for pitching shall be granite or other clean, hard, dense and durable rock free from cracks, kaolinished patches organic or other impurities or deleterious materials and shall be approved by the S.O. The dimension of each stone measured perpendicular to the face of the pitching shall not be less than 150 mm and shall exceed 225 mm for at least 60% of the pitched area. The exposed face of each stone shall not be less than 155 square cm in area. Stone shall be hand placed with closed joints on a layer of gravel or crushed stone to a minimum finished thickness of 225 mm. The sides of stones shall be roughly trimmed with a spalling hammer to obtain a reasonably close fit and the interstices filled with clean coarse aggregate or gravel well rammed and wedged with spalls, the finished pitching shall show an even surface to the lines and levels shown on the Drawings. The joints in pitching shall be raked out to a depth of at least 20 mm and sealed with 1:3 cement/sand mortar finished neatly flushed with the surrounding stones; the stones being left clean of all mortar stains.
11.2
Weepholes
Where indicated on the Drawings or directed by the S.O., weepholes 75 mm in diameter shall be formed by embedded asbestos cement, concrete or glazed stone-ware pipes through concrete members or pitching.
11.3
Rip-rap
Rip-rap shall be hard, sound, broken granite obtained from an approved source, and shall be free from cracks, kaolinised patches, organic or other impurities or deleterious material. Sand and dust shall not exceed 1% by weight. Rock fragments used for rip-rap shall be angular and the greatest dimension of any piece shall not exceed twice the least dimension. The specific gravity of the rock shall not be less than 2.60.
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Section 11 - Drainage Works
Soundness shall be measured by immersion in a solution of Sodium Sulphate of fragments prepared as laid down in Clause 5(b) of ASTM C88 "Method of Test for Soundness of Aggregates by use of Sodium Sulphate or Magnesium Sulphate". The loss in weight after 5 cycles, as defined in ASTM C88, shall not exceed 5%. The material shall be well graded and shall conform to the limits shown in Appendix 2.1.
11.4
Placing Rip-rap
Rip-rap shall be tipped or otherwise placed in such manner as to distribute the sizes uniformly throughout the full thickness of the material; all large voids being filled with smaller rock fragments. It shall be finished finally by hand to the designed slope and thickness. The Contract Rates for rip-rap shall be deemed to include the cost of supplying, handling, placing and any necessary adjustment after dumping to achieve the necessary uniformity of distribution.
11.5
Filter Material
Filter material shall consist of material conforming to the grading limits shown on Appendix 2.1. The gradings and the materials shall be subject to the approval of the S.O. and they shall not be gap graded. The Contractor shall supply to the S.O. grading curves, and samples of not less than 20 kg weight, of each filter material within two weeks after the S.O.’s order to commence work. The S.O. will require simultaneously to see the curves and samples for each category of material which is in contact with another material in the section of the works concerned. Filter material shall be compacted in layers not exceeding 225 mm by 4 passes of a smooth-wheeled vibrating roller. One pass shall consist of as many journeys of the roller as shall ensure that the bearing width of the roller completely covers the layer once. An over-lap of 450 mm between the adjacent paths of the roller shall be maintained. Filter material shall be compacted at the moisture content determined by the S.O. The Contractor shall be deemed to have allowed in his Contract Rates for placing filter material for any watering necessary to achieve the required moisture content. All filter materials shown on the Drawings as vertical layers or layers whose surface is inclined at a slope steeper than one horizontal to three vertical shall be described as filter material in vertical layers. The Contractor shall place filter materials in vertical layers in steps not exceeding 1200 mm deep and shall satisfy the S.O. that the filter material so placed will comply with the specified requirements. The Contract Rates shall allow for all necessary work including excavating and backfilling or the use of temporary formwork to separate different materials or any other operation necessary to comply with these requirements.
11.6
Material for Underdrains and Rubble Drains
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Section 11 - Drainage Works
Material used for sub-soil drains shall be 9.5 mm to 38 mm graded crushed granite, clean and free from silt and clay. Material used for rubble drains shall be graded crushed granite, clean and free from silt and clay as specified in Section 11.1.
11.7
Filter Fabric
The filter fabric employed in the Works shall be as shown in the Drawings and of a make approved by the S.O., and shall be handled and laid strictly in accordance with the recommendations of the manufacturer. The fabric shall be non-woven needle punched type comprising 100% polypropylene continuous fibres and resistant to all naturally occurring soil acids and alkalis and to attack by bacteria and fungi. Fabric manufactured from staples (short) fibres or heat bonded shall not be accepted. The manufacturer shall certify compliance of this requirement. The filter fabric used in the Works shall be the following three types as shown below:• • •
Surround to sub-soil drain pipes. In pipe trench in water logged ground. Under Reno mattress or rip-rap.
The geotextile delivered to site shall meet or exceed the technical values of the following properties. Manufacturer must provide Quality Statement to verify compliance of the technical values. Geotextile not meeting the required technical values shall be rejected. Property
Test Standard
Unit
Type A
Type B
Type C
Ultimate tensile Strength
EN ISO 10319
kN/m
9.5
11.5
24.0
Tensile elongation @ max strength
EN ISO 10319
%
75/35
75/35
80/40
CBR puncture
EN ISO 12236
N
1500
1700
3850
Effective opening size (Wet sieving)
EN ISO 12956
mm
0.12
0.12
0.09
Vertical Permeability (2kPa)
E DIN 60500/4
cm/s
0.3
0.3
0.3
Vertical water flow (2kPa)
E DIN 60500/7
1/sq.m
250
200
103
Mass/area
EN 965
g/sq.m
125
155
325
Thickness
EN 964-1
mm
1.2
1.5
2.9
UV resistance
Outdoor testing
Retain > 80% of max tensile strength after 3 month exposure
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Section 11 - Drainage Works
11.8
Reno Mattresses
Reno mattresses shall be supplied in sizes 5.5 m x 1.8 m in plan with internal diaphragm at 900 mm centres. The mesh size shall be 60 mm and the hot dipped galvanised wire diameter shall be 2 mm coated in PVC giving a minimum of 3.3 mm outside diameter. The mattress filling shall be durable stone graded from a maximum size of 180 mm to a minimum size of 50 mm. After filling the mattresses shall be securely closed and tied to adjacent units with hot dipped galvanised wire not less than 2 mm diameter. Each mattress shall be staked to the ground with a 20 mm galvanised mild steel rod 1200 mm long. Reno mattresses shall be measured as the net volume laid and shall include the stone filling, securing stakes and wire.
11.9
Gabions
Gabions shall be supplied in sizes 2 m x 1 m x 1 m. The mesh size shall be 100 mm and the hot dipped galvanised wire diameter shall be 2.7 mm coated in PVC giving a minimum of 3.8 mm outside diameter. The gabion filling shall be durable stone of maximum dimension of 300 mm and minimum dimension of 150 mm. After filling, the gabions shall be securely closed and tied to adjacent units with galvanised wire not less than 2 mm diameter.
11.10
Porous Concrete Pipes
Porous drainage pipes shall be ogee porous concrete pipes complying with BS 5911-114. Porous pipes shall be laid dry jointed as detailed in the Drawings or as directed by the S.O. and surrounded by drain material. Unless otherwise shown on the Drawings, precast concrete channels shall be at least cast in concrete grade C20 and shall be dense, homogeneous channels with clean true edges and surfaces. The drain channels shall be reinforced with fabric reinforcement as shown on the Drawings or as required. Channels shall, unless otherwise stipulated, be bedded on concrete grade C20 base of required thickness, all joints (6 mm maximum) shall be grouted and pointed in cement mortar (1:3).
11.11
Salt Glazed Stoneware Pipes and Fittings
All salt glazed stoneware drain pipes and fittings shall comply with BS 65 or an equivalent standard. The pipes shall be laid carefully to the lines and gradients shown on the Drawings or as directed by
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Section 11 - Drainage Works
the S.O. Chemically resistant salt glazed ware drains conforming with BS 65 are required for certain of the surface water drains. They shall be well glazed and impervious and free from fire cracks and other defects. The pipes shall be jointed by first placing into the socket a ring of tarred yarn and then by filling the remainder of the cavity with 1 to 1 1/2 cement sand mortar. The joint shall be finished with a neat 45o fillet worked round the outside. The tarred yarn when rammed into position shall not occupy more than one quarter of the depth of the socket. A suitable scraper shall be drawn through each pipe immediately after laying to remove any jointing material to leave a clear and unobstructed waterway. All salt glazed ware pipes shall be bedded and haunched or surrounded with 150 mm thick Grade C20 concrete as directed by the S.O. They shall be fully surrounded in concrete where they are under buildings and roads or where the cover to the crown of the pipe is less than 1 metre or greater than 2 metre.
11.12
Reinforced Concrete Pipes
Reinforced concrete pipes shall be manufactured and tested in accordance with MS 881. Pipes shall be spigot and socket ended suitable for rubber ring joints and supplied in standard lengths of 1.52 m. Rubber rings shall be manufactured in accordance with BS 2494. All pipes shall be hydraulically tested in the manufacturer's works. The Contractor shall despatch duplicate copies of test certificates certifying that the pipes comply fully with the Specification.
11.13
Clayware Field Drain Pipes and Fittings
All clayware fields drain pipes and fittings shall comply with the requirements of BS 1196: 1971.
11.14
Laying Drain Pipes
All drain pipes shall be laid with the sockets leading uphill and shall rest on solid and even foundations for the full length of the barrel. Socket holes shall be formed in the bed of the trench to allow sufficient room for the proper making of the joints. Each separate pipe shall be set for line and level using a boning rod.
11.15
PVC Pipes
PVC drain pipes shall be of Class C unplasticised PVC pipes complying with BS 3505. Pipe ends shall be suitable for jointing with approved patent joints. Pipes which are to be used as underdrains under the slabs of the reservoirs or tanks shall be plain ended suitable for butt joints and shall be perforated. The perforations shall be 15 mm diameter each. Four perforations shall be made on each cross section of the pipe and shall be spaced equally. Perforations along the pipe shall be spaced at 150 mm centres.
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Section 11 - Drainage Works
11.16
Drain Pipe Test Certificates
Each batch of pipes supplied shall be accompanied by the manufacturer’s test Rain water pipes shall be measured as the net length erected in place and shall include for all works in forming bends where required, cutting, jointing and building into concrete, providing and erecting support brackets for holding the pipe in position.
11.17
Drain Covers and Gratings
Provide mild steel gratings and precast reinforced concrete grade C20 covers to drains, to details as shown on Drawings, and at areas where required.
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Section 12 - Miscellaneous
12.0
MISCELLANEOUS ....................................................................................12-1 12.1
Chequer Plating .............................................................................12-1
12.2
Handrailing .....................................................................................12-1
12.3
Ladder.............................................................................................12-1
12.4
Step-irons .......................................................................................12-2
12.5
Manholes, Surface Boxes, etc ......................................................12-2
12.6
Fencing ...........................................................................................12-2
12.7
Galvanised Metals .........................................................................12-3
12.8
Dissimilar Metals ...........................................................................12-3
12.9
Painting...........................................................................................12-3 12.9.1
General ...........................................................................12-3
12.9.2
Painting Procedure........................................................12-4
12.9.3
Painting Timber Surface ...............................................12-5
12.9.4
Painting Steel and Ironwork .........................................12-5
12.9.5
Painting Concrete and Cement based Surfaces .........12-6
12.9.6
List of Approved Paints ................................................12-6
12.9.7
Painting Colour Code ....................................................12-6
12.10 Sealing Compounds ......................................................................12-8 12.11 Joint filler........................................................................................12-9 12.12 Waterstops .....................................................................................12-9 12.13 Building Paper ...............................................................................12-9 12.14 Interlocking Concrete Pavement Block .......................................12-9 12.15 Anchor Bars .................................................................................12-10 12.16 Fibreglass Reinforced Plastic (FRP) Fabrications....................12-11 12.16.1
General .........................................................................12-11
12.16.2
Products .......................................................................12-12
12.17 Fibreglass Reinforced Plastic (FRP) Gratings and Stair Treads...........................................................................12-13 12.18 Fibreglass Reinforced Plastic (FRP) Handrails.........................12-13 12.19 Fibre Reinforced Plastic (FRP) Covers ......................................12-14 12.19.1
General .........................................................................12-14
12.19.2
Design...........................................................................12-14
12.19.3
Materials .......................................................................12-19
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Section 12 - Miscellaneous
12.19.4
Workmanship ...............................................................12-21
12.19.5
Inspection and Testing................................................12-23
12.19.6
Water Supply System ..................................................12-27
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Section 12 - Miscellaneous
12.0
MISCELLANEOUS
12.1
Chequer Plating
Chequer plating shall be hot-dip galvanised mild steel in accordance to ISO 1461 and shall have a non slip pattern on its upper face. Chequer plates shall be securely bolted with countersunk screw studs to frames set in the edges of and spanning the ducts or opening. Chequer plates for use in valve chambers or manholes shall be hinged to one side of the frames unless otherwise specified. The sizes of chequer plates shall be such that no discernible deflection occurs under the weight of a man standing upon it. Where it is not practicable to provide individual frames to each plate, the plates shall be stiffened by welding steel angles on their underside to eliminate discernible deflection. The plate panel sizes shall be such that they can be lifted by two men easily and each panel shall be provided with suitably sized lifting holes. The edges of all chequer plates shall be finished straight or to the outline of obstructions and shall be free of burn marks or irregularities. Chequer plating which has been cut with a torch shall afterwards be ground to present a straight edge. Chequer plating shall be painted with two coats of two pack epoxy based red lead primer before delivery. After installation on Site, chequer plates used in valve chambers shall be fully painted with a further two coats of two pack coal tar epoxy paint. Chequer plates used elsewhere shall be painted on the lower (hidden) surfaces with two coats of similar coal tar epoxy paint and on the upper (exposed) surfaces with one undercoat, two coats of semi-gloss high finishing paint of approved quality and colour.
12.2
Handrailing
Handrailing shall be made from hot-dip galvanised mild steel hollow sections and flats. Any distortions or warping of the handrails as a result of the hot-dip process is unacceptable and prior to installation all lengths of handrailing shall be inspected for straightness and approved by the S.O. After cleaning with lithoform, it shall be painted with two coats of two pack epoxy red lead primer, an undercoat and a further 2 coats of an approved gloss paint after installation. Expansion units shall be provided where the handrailings are more than 15 metre long.
12.3
Ladder
Mild steel ladders shall be hot-dip galvanised in accordance with BS EN ISO 1461. After cleaning with lithoform it shall be painted with two coats of approved two pack coal tar epoxy paint which shall be obtained from an approved manufacturer. Unless detailed on the Drawings, the Contractor shall submit to the S.O. detailed drawings of the ladder for approval before placing any orders. Steel ladders shall be 450mm wide, of welded construction and shall not have an unsupported length of more than 2 metre unless otherwise specified. Intermediate support between the ends of the ladder shall be by means of stays securely fixed to the nearest part of the structure.
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Section 12 - Miscellaneous
The steel ladders shall be galvanised before leaving the manufacturers' works and supplying and fixing steel ladders shall include for painting as specified, and for all nuts, bolts, stays and other things necessary for fixing the ladders securely in place.
12.4
Step-irons
Step irons for use in chambers unless otherwise specified shall be bent from 25mm diameter deformed high yield steel bars to the shape and dimensions shown on the Drawings and shall be hot-dip galvanised after bending. Step irons shall be painted with 2 coats of approved two pack coal tar epoxy paint.
12.5
Manholes, Surface Boxes, etc
Ductile iron manhole and access covers, surface boxes, gulley grating and frames unless otherwise specified shall be obtained from an approved manufacturer and shall comply with BS EN 124. Access covers and surface boxes exposed to the weather shall incorporate a waterproof seal. Pan type duct covers to receive a floor finish shall be Broads Stelduct or similar subject to the approval of the S.O. They shall be partially filled with concrete ready to receive the floor finish specified. Frames shall be firmly bedded in 1:3 cement/sand mortar and the tops of all covers and gratings shall be flush with the finished surface of the surrounding floor, ground or pavement. Four sets of each type of lifting key shall be supplied by the Contractor.
12.6
Fencing
The boundary of a treatment plant, pumping station and/or sludge treatment facility shall be secured by 3.0 meter high fence. The perimeter fence shall have an entrance by double gates or sliding barrier to allow access of maintenance vehicles. The gates shall be secured by padlocks and shall comply with the requirements of the Commission. Where the treatment plant is situated in a building, access to the plant must be secured. Typical details of the fence are as shown in Developer Guideline Volume 4. Fencing shall be as detailed on the Drawings. Contractor is required to provide adequate warning/safety and the Commission signboard before handing over the sewerage system to the Commission. Brickwall Fencing The fence shall be at least 2.2 meter high solid brick wall with three strands of 0.8 meter high barbed wire. Barbed wires shall be galvanised two ply 2.64mm with 4 point barbs spaced at 75mm intervals. Precast Concrete Fencing The fence shall be 2.2 meter high solid precast concrete wall with three strands of 0.8 meter high barbed wire. Mosony Fencing high barbed wire.
The fence shall be 2.2 meter high masony wall with three strands of 0.8 meter
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Section 12 - Miscellaneous
Gate Chain link for gate shall be PVC coated and consist of hot dipped galvanised 4.06mm wire of 50mm square mesh reinforced with 3 No. 4.06 mm hot dipped galvanised line wires. Fence posts for gate shall be of 64 mm x 64 mm x 9.4 mm hot dipped galvanised mild steel angles spaced at 3.0 metre intervals with straining posts at all corners and at intervals of 15 metre. Stays for straining posts shall be 51 mm x 51 mm x 6.3 mm hot dipped galvanised mild steel angles raked at 45o. All mild steel angles shall be galvanised and painted in accordance with BS 5493. All fence posts and struts shall be sunk into post holes 300 mm x 300 mm x 750 mm deep, and filled in with Grade C20 concrete to be flushed with the ground level unless otherwise shown in the Drawings. Installation of fencing shall include for the supply of all materials, galvanising, excavation, erection of the fencing complete painting with 2 coats of approved paint, fence posts, stays corner posts, concrete support and up stand beam.
12.7
Galvanised Metals
All metals to be galvanised shall be of the full dimensions shown or specified in accordance with ISO 1461 and all punching, cutting, drilling, screw tapping, welding and the removal of burrs shall be completed before the galvanising process commences. All galvanising shall be done by the hot-dip process with spelter, not less than 98% of which shall be pure zinc. Bolts, nuts and washers shall be completely galvanised including the threads but galvanising removed in the course of nut fixing may be replaced with an approved zinc rich paint. The galvanising shall be uniform, clean, smooth and as free from spangle as possible. It shall weigh not less than 6.00 grams per square metre of area covered and be not less than 0.1mm thick. All galvanised metal parts shall be protected from damage due to electrolytic action, white rust and abrasion during delivery, storage and erection. Minor damage shall be touched up with an approved zinc chromate or other approved metallic compound but if, in the opinion of the S.O. the damage to the galvanising is too severe or extensive, the part shall be removed and be re-galvanised.
12.8
Dissimilar Metals
The Contractor shall not use fixtures and fittings for metalwork including pipework in which dissimilar metals likely to lead to galvanic action are placed in permanent contact with each other.
12.9
Painting
12.9.1
General
Painting shall comply with the requirements of BS 6150 and Recommendations for Painting in Tropical Climates (Building Research Station - Tropical Building Studies No. 4) All paints and painting materials used in this Contract shall be of the best quality suitable for tropical climate and approved by the S.O. Undercoats shall be of distinctive tints and finishing colours shall be approved by the S.O. Paints shall be delivered to site in their original containers, sealed and intact. All materials and costs of each type shall be of the same manufacturer.
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Section 12 - Miscellaneous
12.9.2
Painting Procedure
The Contractor shall follow strictly in accordance with the manufacturer's instructions and recommendations based on BS 6150, particularly with regard to:a)
Preparation of surfaces specified to be painted.
b)
Preliminary priming or sealing coat.
c)
The number of undercoats and method of application.
d)
The finishing coat and method of application.
As the painting work proceeds, each coat of paint shall differ slightly in colour or shade from the preceding coat. The finishing coat, when dry, shall be the colour selected. The finished surface shall be uniform in colour and free from brushmarks. No painting shall be carried out when the atmosphere is dusty or wet or when the surface to be painted is hot. Adequate ventilation shall be provided for the proper application and curing of the paint-work and for the safety and health of the painters. Care shall be taken to protect floors, roofs and any other adjacent areas or installations by covering them with drop cloths or other similar approved means. Except as required for surfaces on which emulsion or water thinned paints are to be applied, painting shall be done only on surfaces which are thoroughly clean and dry, and at such humidity and temperatures of the atmosphere and of the surfaces to the painted as will cause evaporation of moisture rather than condensation. Surfaces which have been cleaned, pretreated and/or otherwise prepared for painting shall be primed as soon as practicable after such preparation has been complete but before deterioration of the prepared surface. Paint shall not be applied to any surface which is excessively hot for the type of paint being used, and freshly painted surfaces shall be shaded and protected from overheating until sufficiently hardened to prevent the occurrence of cracking or blistering. Painted exterior surfaces shall be protected from the weather until the paint is thoroughly dry and hard. Painted woodwork and metalwork shall be lightly rubbed down with glass paper between coats and dusted down. At least 24 hours shall elapse between the application of successive coats unless otherwise specified by the manufactures. Final coats shall only be applied after clearing up and finishing by all other trades has been completed. On completion of painting, the Contractor shall remove all paints, spots and shall touch up or re-paint imperfect work. Unless otherwise specified by the manufacturers, at least 24 hours shall elapse between the application of successive coats. However, in no circumstances shall the time between coats exceeds the following: a)
between application of primer and undercoat
-
3 weeks
b)
between undercoats or under coat and first finishing coats
-
2 weeks
c)
between gloss finishing coats
-
48 hours
Should the above times be exceeded the Contractor shall recoat the work which has been weathered beyond the specified time, with a coat equal to that previously applied, at his own expense. Typical Civil and Structural Engineering Specification for Sewerage Works Issue 01 / Rev 0 August 2008
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Section 12 - Miscellaneous
12.9.3
Painting Timber Surface
Timber surfaces to be painted shall be examined for sap, grease, and oil, and shall be removed and cleaned. Any holes, cracks and joints shall then be neatly stopped with putty. All mortar splashes, excessive roughness, loose edge shall be sanded with sandpaper. All protruding and exposed nails shall be punched beneath surface and puttied. All frames and other external timber specified to be painted shall be knotted, stopped and primed with one coat of an approved aluminium primer before erection. Joinery shall be primed before assembly. Cut ends must be primed before fixing. End grain faces and covered faces which cannot be painted further after erection shall be given two coats of aluminium primer. The sequence of painting timber surfaces after priming shall be a)
one further priming coat
b)
one under coat
c)
two high gloss finishing coats
of paint suitable for interior or exterior use depending on the recommendation of the manufacturers. Unless otherwise specified, hardwood shall be stained and treated with two coats of long oil formulation type of varnish after erection as directed.
12.9.4
Painting Steel and Ironwork
Unless galvanised, all steel and ironwork shall be supplied with two coats of two pack epoxy based red lead oxide primer before leaving the manufacturer's works. The Contractor shall examine and make good any damage in the surface due to delivery, handling and erection. Steelwork and ironwork to be embedded in concrete shall be painted with an additional coat of similar primer and made good before it is built into the concrete. Steelwork and ironwork to be embedded in brickwall shall have two additional coats of bituminous paint and made good before it is built into the brickwall. After erection and building in, all exposed surfaces of steelwork and ironwork which are not completely painted shall be cleaned, filled and painted with one flat undercoat and three coat semi-gloss high finishing paint approved by the S.O. Items which will be submerged in water or exposed to outside atmosphere or in manholes shall be given two coats of approved bituminous epoxy enamel. Where in contact with water, the enamel shall be taint free, non-toxic and chlorine resistant. Items which are supplied bitumen primed shall be given two coats of approved metallic sealer. Items supplied with red lead primer shall be given a further priming coat. In both cases they shall be painted with one flat undercoat and two coats of high gloss finish. All galvanised steel to be painted shall be washed with ICI lithoform or other similar approved material and then applied with an approved etching primer before applying the standard primer. It is then followed by an undercoat and two coats of epoxy paint.
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Section 12 - Miscellaneous
Aluminium work shall not be painted except those surfaces to be built into concrete, which shall be cleaned down and given two coats of an approved bituminous paint. The paint shall be thoroughly dry before placing the surrounding concrete. All painting works for structural steel works shall strictly refer to Section 7.0 and in accordance to BS 5493.
12.9.5
Painting Concrete and Cement based Surfaces
All concrete and cement based surfaces to be painted shall be dried to the satisfaction of the S.O. before painting is commenced, and all dust, dirt, plaster splashes or efflorescence shall be brushed off and removed by dry brushing. Any cracks, blister or other imperfections shall be rubbed down, smoothed, cut out and made good. The surfaces excepting the lime silo storage areas shall be given a coat of an approved alkali resisting primer and one undercoat followed by two finishing coats of approved undiluted super acrylic emulsion paint with fungicide additive. The lime silo areas shall be given primer and undercoat as above and followed by two finishing coats of super gloss paint. The floor of liquid alum storage area shall be painted with two coats approved epoxy based paint according to manufacturer's specification.
12.9.6 List of Approved Paints The paint shall be of the type and make as approved by S.O.. If the tender is accepted, the Contractor shall supply and paint the type of building as stated in the Schedule. No substitution shall be allowed without the prior approval of the S.O. The colour standard / painting system index for buildings and piping shall comply to IWK’s requirement as shown the Appendix.
12.9.7 Painting Colour Code Painting shall include all plant and machinery inside buildings, including pipework, grating, handrailing, internal walls below ground level and all metal work including machinery. Conduits and piping shall be appropriately named and labelled indicating flow directions and painted with the following colour codes for easy identification:
•
Chlorine line
- yellow with double green bands
•
Compressed air line
- green
•
Fuel gas line
- orange
•
Potable water supply line
- blue
•
Raw sewage line
- black
•
Final effluent line
- grey
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Section 12 - Miscellaneous
•
Sludge line
- brown
•
Non-potable water line
- blue with double black bands
•
Other disinfectant lines
- yellow with double red bands
•
Biogas line
- yellow
The labels shall be stencilled on the piping in a contrasting colour with the colour coded bands, if any, located at appropriate and strategic points. Colour codes selected for general equipment, building and others items in a sewage treatment plant shall be adhered to colour standards as detailed in the table below. The types of paint and surface preparation used shall be as recommended by the paint manufacturer. Painting shall include all plant and machinery inside buildings, including pipework, grating, handrailing, internal walls below ground level and all metal work including machinery. Painting System Index – Colour Standards Item
Colour
Equivalent Colour Guide
General Equipment including motors (unless come with the original manufacturer approved colour code)
Dark Blue
Penstocks/Valves/Manhole Covers
Black
Dulux Regal Blue 0013 Par Mandarin Blue 0013 Par Bituminous Black
Machinery Guards/Railings/Runways/Overhead Cranes/Lifting Davit
Yellow
Dulux Lemon 2024 Par Golden Yellow
Switchboards
Fencing poles/Gates
Building and Walls – Exterior Building and Walls - Interior Fencewall – Interior and Exterior
Light Grey
Dulux Pewter 695
Green
Par Willow Grey 00A05 Dulux A365-13449
Grey (Weathersheild) White Grey
Typical Civil and Structural Engineering Specification for Sewerage Works Issue 01 / Rev 0 August 2008
Par Green 3666 Dulux BS 00A0510235 Dulux BS 00A0510235
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Section 12 - Miscellaneous
Item
Colour
Equivalent Colour Guide
Floors - Concrete Interior
Green
Leigh Green 3666
Green
Dulux A910-13448 Par Green 3666 Dulux A910-11482
Building Stripes
Green Blue
Indah Water Logo (where applicable)
Green
Indah Water Green
Par Blue 2686 Dulux A365-13449 Par Green 1006
Blue
Indah Water Blue Indah Water Blue
Dulux A365-11483 Par Blue 1007
Notes The above painting requirements are not applicable to stainless steel, aluminium, galvanised metal surfaces except where necessary to comply with statutory health and safety requirement.
12.10
Sealing Compounds
a)
Construction and contraction joints
Sealing compounds for horizontal joints shall be hot applied bituminous sealants complying with the requirements of BS 2499 and BS EN 14188. The sealing compound shall be capable of expanding to 110% of its original thickness between parallel faces without separation. Horizontal joints to be filled with the sealing compound shall first be thoroughly cleaned and dried before applying primer compatible with the sealing compound to be used. Both primer and sealing compound shall be applied in accordance with the manufacturer's recommendations for tropical climates. Sealing compounds for vertical and inclined joints shall be bituminous putty of a quality approved by the S.O. The sealing compound shall be capable of expanding to 110% of its original thickness between parallel faces without separation. Vertical and inclined joints to be filled with the sealing compound shall first be thoroughly cleaned and dried before applying an approved primer compatible with the scaling compound to be used. Both primer and sealing compound shall be applied in accordance with the manufacturer's recommendations for tropical climates. b)
Expansion joints
Sealing compounds for expansion joints shall be polysulphide liquid polymer sealants obtained from approved manufacturers. The sealing compound shall be capable of expanding to 133% of its original thickness between parallel faces without separation and contracting to 67% of its original thickness without extruding.
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Section 12 - Miscellaneous
Expansion joints to be filled with the sealing compound shall first be thoroughly cleaned and dried before applying an approved primer compatible to the sealing compound to be used. Both primer and sealing compound shall be applied in accordance with the manufacturer's recommendations for tropical climates.
12.11
Joint filler
Joint filler for all joints in water retaining structures shall be resin bonded cork filler or similar approved product and shall be obtained from approved manufacturers.
12.12
Waterstops
Waterstop shall be dense, homogeneous and free of holes or other imperfections. The cross section shall be uniform along the length and symmetrical transversely so that the thickness at any given distance from either edge will be uniform. Where not otherwise shown on the Drawings:-
the width of the waterstop shall not be less than 80% of the thickness of the concrete section and not less than 225mm; the web thickness shall be not less than 9mm. all waterstop shall incorporate a solid bulb or major rib at or near each edge; waterstop at movement joints shall incorporate a central hollow bulb; waterstop for use at induced contraction joints shall incorporate a crack inducer; waterstop for use within the concrete thickness shall be of rubber.
Rubber waterstop shall be of natural rubber, suitable synthetic rubber, or a blend of the two and shall have the following properties when tested at 25°C.
Minimum tensile strength (N/mm2)
18
Minimum elongation at break (%)
450
Hardness (IRHD/Shore ‘A’) Softness (BS 2571) Specific gravity
60-70 1.05 - 1.15
All intersections and junction in waterstop shall be factory-produced by the manufacturer of the waterstop, normally as moulded special pieces, so that the only joints remaining to be made at Site shall be straight butt joints between straight length of waterstop of the same section and material.
12.13
Building Paper
Building paper shall be waterproof Class A complying with BS 1521.
12.14
Interlocking Concrete Pavement Block
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Section 12 - Miscellaneous
a)
General
'UNI-PAVE' interlocking concrete pavement blocks shall be laid to all apron slab areas as indicated in the Drawings or as directed by the S.O. Concrete pavers shall be 225 x 113 x 60 mm thick laid to patterns and colours as selected by the S.O. b)
Workmanship
The sub-base shall be evenly compacted by a vibrating plate compactor. The sub-base construction should extend beneath any new edge restraints constructed as part of the pavement and be closely trimmed to the required levels. Edge restraints in the form of cast in-situ concrete (1:3: 6-1½" aggregate) shall be provided along the edges of "UNI-PAVE' pavements. The restraints shall be cast in such a manner that they are slightly lower than the adjacent paving units for surface water drainage. A sand blinding layer, comprising well-graded concreting sand shall be spread and screened and compacted to consolidated thickness of 30mm to receive the "UNI-PAVE" units. The laying of "UNI-PAVE" units shall commence from the lowest level edge restraint. The units shall be laid with 2 to 4mm gap between adjacent units. Immediately after laying, the units shall be compacted and brought to level with the vibrating plate compactor. Upon completion of compaction, sand of 2mm size should be broomed over the pavement and into the joints. Excess sand should be removed as soon as joints are filled.
12.15
Anchor Bars
a)
General
Anchor bars shall consist of untensioned straight or L shaped mild steel or high yield bars, as shown on the Drawings and/or as directed by the S.O., and which are fully grouted into the foundation in order to anchor down concrete structure placed onto the foundation. The anchor bars shall be grouted into holes of nominal diameter which are 25mm larger than the anchor bar diameter and drilled to such depths, inclinations and orientations as directed by the S.O. The grout shall be a non-shrink cement grout of Ordinary Portland cement with a water cement ratio of not more than 0.45 with approved admixtures. The grout strength shall be 30N/mm2 at 28 days. Materials for the grout shall be as that specified in Section 3.0 Concrete. b)
Installation Sequence
Anchor bars shall be installed in the following sequence: i)
drill the hole to the length and diameter required;
ii)
flush out hole with a high pressure air and water jet until return water is clear;
iii)
remove any standing water by means of compressed air;
iv)
fill hole with grout through a plastic tube extending to the base of the drillhole to ensure that all air and water are displaced by the grout;
v)
install anchor bar centrally in hole by means of approved spacers;
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vi) c)
top up grout level as required.
Pull Out Tests
Prior to the installation of the permanent anchor bars the Contractor shall carry out Pull Out Tests on trial or working anchor bars selected by the S.O. The Contractor shall provide all torque wrenches, jacks and other equipment necessary to test the anchor bars. Before the test is carried out the Contractor shall submit to the S.O up to date certificate of calibration for the test equipment to be used for the testing. The Contractor shall submit the proposed testing procedures to the S.O. for his approval before commencing any test. Anchor bars for the Pull Out Test shall be tested to 1.5 x working load or to the specified load and the mode of failure, if any, recorded. The test result shall be accepted if the bar remained in place under the test load for 5 minutes. Modifications required as a result of the Pull Out Tests shall be approved by the S.O. before the Contractor commences the drilling for the permanent anchor bars. n no case shall the drilling for the permanent anchor bars commence until the S.O. has accepted and approved the results of the Pull Our Tests and confirm whether any modification is required or not.
12.16
Fibreglass Reinforced Plastic (FRP) Fabrications
12.16.1 General Description
The wok included in this section comprises furnishing all plant, labour, equipments, appliances and materials and performing all operations in connection with fibre reinforced plastic fabrications. Submittals
a)
Product data shall include manufacturer’s catalog data showing dimensions, spacings, and construction details; design tables showing limits for span length and deflection under various uniform and concentrated loads; materials of construction.
b)
Shop drawings shall detail fabrication and erection of each FRP fabrication including plans, elevations, sections, and details of FRP fabrications and their connections, anchorages and accessory items.
c)
Samples of each type of FRP product proposed shall be submitted for approval.
Quality Assurance
a)
Material shall be furnished by a reputable and qualified manufacturer of proven ability who has regularly engaged in the manufacture and installation of FRP systems and shall be approved by the Engineer.
b)
Fabricator shall be a firm experienced in successfully producing FRP fabrications similar to that indicated for this project, with sufficient production capacity to produce required units without causing delay in the work.
c)
Substitution of any component or modification of system shall be made only when approved by the Engineer and at no additional cost to the Employer.
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Section 12 - Miscellaneous
d)
In addition to requirements of these specifications, the Contractor shall comply with manufacturer’s instructions and recommendations for work.
Delivery Storage and Handling
a)
All systems, sub-systems and structures shall be shop fabricated and assembled into the largest practical size suitable for transporting.
b)
All materials and equipments necessary for the fabrication and installation of the grating, stair treads, handrails, ladders, weir plates, linings and structural shapes shall be stored in a manner to prevent cracking, twisting, bending, breaking, chipping or damage of any kind to the materials or equipment, including damage due to over exposure to the sun.
c)
All material which, in the opinion of the Engineer, has become damaged as to be unfit for use, shall be promptly removed from the site of works and the Contractor shall receive no compensation for the damaged material, or its removal.
d)
All materials, items and fabrications for installation and field assembly shall be identified and match-marked.
12.16.2
Products a)
The Contractor shall design, engineer, fabricate, and install the FRP fabrications to withstand the specified structural loads without exceeding the allowable design working stress of the materials involved, including anchors and connections. Each load shall be applied to produce the maximum stress in each respective component of each FRP fabrication.
b)
Materials used in the manufacture of the FRP products shall be new stock of the best quality, free from all defects and imperfections that might affect the performance of the finished product.
c)
All materials shall be of the kind and quality specified, and where the quality is not specified, it shall be the best of the respective kinds and suitable for the purpose intended.
d)
All FRP products shall be manufactured by a pultruded process using a vinyl ester resin with flame retardant and ultra-violet (UV) inbibitor additives. A synthetic surface veil shall be the outermost layer covering the exterior surface and FRP shapes shall achieve a flame spread of 25 or less in accordance with ASTM test method E84.
e)
All FRP items shall be corrosion resistant to a 5% concentration of either sulphur dioxide or hydrogen sulphide.
f)
After fabrication, all cut ends, holes and abrasions of FRP shapes shall be sealed with a compatible resin coating to prevent intrusion of moisture.
g)
FRP products exposed to weather shall contain an ultraviolet inhibitor and shall additionally receive 25 microns thick U.V. coating to shield from ultra-violet light.
h)
All exposed surfaces shall be smooth and true to form.
i)
Color shall be OSHA safety yellow or gray as gray as instructed by the S.O.
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12.17
Fibreglass Reinforced Plastic (FRP) Gratings and Stair Treads
Compliance
The FRP products shall comply with the ASTM Testing and must be approved by S.O. Material
FRP gratings shall be manufactured by open molding process. The material shall combine fibreglass rovings with at least 65% thermosetting resin by weight to form a strong, one-piece molded panel and provide corrosion resistance characteristic. It shall offer outstanding resistance to a wide range of highly corrosive situations found in wastewater applications. The quality of product shall be assured subjecting to extreme tests for chemical resistance, stability under ultraviolet exposure, impact resistance, load carrying capacity and strength. Unless otherwise stated, the mesh size shall be 25mm, 35mm or 50mm square mesh which is able to provide bi-directional strength. Design
Molded FRP grating span should be limited to an acceptable deflection. Gratings must be mechanically fastened in place to prevent sliding. Each grating panel should be fastened to each supporting structure using a minimum of four “M” style hold down clips. For larger panels, 6 to 8 hold down clips are recommended. Gratings installed in trenches where they are captive in an embedment angle do not require hold downs unless bearing surfaces are uneven and the grating panels would tend to rock. Abutting edges of molded grating panels should be supported by structural members or fastened together using “F” style to clips at a minimum spacing of 600mm on centre. This will prevent differential deflection when one of the abutting gratings is loaded. The top surface of all panels shall have nonskid grit affixed to the surface by a baked epoxy resin followed by a top coat of baked epoxy resin.
12.18
Fibreglass Reinforced Plastic (FRP) Handrails
Material
The material shall have a glass reinforcement content of 50 %. The glass fibre ‘E’ type continuous strand glass mat or continuous glass strand glass mat or continuous glass strand rovings shall comply with BS 3749, rails and posts shall be 50x50x4 mm thick fibre glass pultruded square tube, kickplates shall be 100 x 12.5 (corrugated) x 3 mm thick pultruded fibre glass shape.
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Section 12 - Miscellaneous
Pultruded parts shall meet the following minimum mechanical properties: Properties
Tensile Stress Tensile Modulus Compressive Stress Compressive Modulus Flexural Stress Flexural Modulus Shear Stress Density 24 hr. Water Absorption Coef. Of Thermal Expansion Flexural Stress Flexural Modulus
Test Method
ASTM D638 ASTM D638 ASTM D695 ASTM D695 ASTM D790 ASTM D790 ASTM D2344 ASTM D792 ASTM D570 ASTM D696 Full Section Full Section
Values
207 MPa 17 GPa 207 MPa 17 GPa 207 MPa 11 GPa 31 MPa 1.66 to 1.94 g/cm2 max 0.6% 8 x 10-6 /oC 248 MPa 25 GPa
Design
Design shall conform to loading requirements of OSMA 1910.23, with a minimum factor of safety of 2. Fabrications shall be capable of withstanding a concentrated load of 90 kg applied at any point nonconcurrently, vertically downward or horizontally. Horizontal hand rails shall be 1000mm high with an intermediate rail at 500mm high.
12.19
Fibre Reinforced Plastic (FRP) Covers
12.19.1 General a)
Scope
This part of the Specification covers the design, manufacture, supply, installation and testing of glass fibre reinforced plastic (FRP) covers for tanks, channels and vessels that contain sewage and sludge. The purpose of the covers is to prevent the emission of gases and offensive odours. b)
Manufacturer
The manufacturing of the FRP covers shall be undertaken by a specialist firm with at least five years experience in the design and fabrication of large FRP elements comparable to those required for this Contract.
12.19.2 Design a)
Submissions by the Contractor
The detail design of the covering systems, including the structural design, all fixings and support details, is to be prepared by the Contractor and submitted to the S.O. for approval. The detail designs submitted by the Contractor shall be undertaken by a Qualified Person experienced in the design of FRP structures. The Contractor shall submit such calculations in a format required by the S.O.
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Comprehensive calculations shall be prepared for each configuration of cover to accompany the designs as submitted. These calculations shall be carried out in accordance with established practice for FRP structures, and reference shall be made to standards such as BS 4994, NF T 57 – 900 and DIN 18820 where these are appropriate. The calculations and design drawings shall be in English. Where reference is made by the Contractor to standards or other documents which are not in the English language translations shall be provided by the Contractor at the same time that the calculations and designs are submitted. The calculations shall determine the following maximum stresses: -
tension: longitudinal and lateral; compression: longitudinal and lateral; shear: in-plane, inter-laminar and punching; bolt bearing
The corresponding strains shall also be determined. Calculations shall be carried out to demonstrate that there will be no instability of any kind when the covers subjected to twice the worst practical combination of factored loads. The calculations shall include a determination of the maximum loading which will be applied to the tank structure. Where computer programs have been used in the design process full listings of input and output data shall be provided together with a detailed assessment of the salient aspects of the analysis. When required by the S.O. a copy of the used manual for any computer program shall also be provided. The covers shall be fabricated in strict accordance with the designs for which the S.O. has granted final approval. b)
Design Requirements
The covers and any associated support systems shall be designed to be suitable in all respects for their proposed use. They shall be capable of withstanding the design loading conditions given below without exceeding the allowable stresses and strains, while remaining airtight. The maximum allowable stress shall be related to the measured strength of the proposed laminate as specified below. The covers shall be designed to withstand the loadings which will result from the impact tests specified below. The covers shall be designed to be air-tight with the exception of purpose designed air inlets and pressure relief devices which form part of the ventilation and odour control system. c)
Design Loading
The design loading for the covers comprises: i.
An imposed load of 0.50 kN/m2 or a concentrated load of 0.9 kN, whichever produces the greatest stress;
ii.
An abnormal loading of 1.00 kN/m2 because of the pressure differential across the cover which may result from the operation of the ventilation system;
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iii.
A wind loading determined in accordance with the requirements of BS 6399: Part 2 using a design wind speed of 32 m/s;
iv.
The self weight of the covers and any additional supports;
v.
Any additional loadings for individual covers;
vi.
Any additional loadings which will be imposed upon the covers by virtue of the proposed design, the proposed method of lifting cover segments or the proposed method of installation.
All covers shall be designed to limit state structural design principles. The following load factors shall be applied to the design loads given above: Load case 1 2 3 4
Loads i) + ii) + v) + vi), and iv) iii) + iv) iii) + any other loads vi)
Load factor 1.6 1.4 1.2 1.2 1.0
An additional unbalanced loading case (load case 5) shall be considered in which the design loads shall be as for load case 1 except that the imposed loading of 0.50 kN/M2 shall be applied to one half of the cover only. d)
Allowable Stresses, Strains and Deflections
Under the worst combination of the above factored loads, and any other effects such as temperature variations, the stresses in the cover shall everywhere be less than the allowable stresses which shall be determined by making appropriate reductions to the minimum laminate strengths to allow for the following factors: -
long-term loading; the method of manufacture; the chemical environment to which the covers are to be exposed; elevated temperatures; cyclic loading; curing procedure
The amount of these reductions shall be determined in accordance with established procedures such as those set out in Section 9.2 of BS 4994. An additional reduction to the minimum laminate strength to allow for the effect of long term exposure to UV radiation shall be made. The amount of this reduction shall be substantiated by the Contractor with specific reference to the proposed resins, UV absorbers and light stabilisers. The maximum strain shall not exceed 0.2%, or 10% of the extension to failure (fracture strain) of unreinforced resin determined in accordance with Appendix B of BS 4994, whichever is the smaller. Under the worst combination of the above unfactored loads no section of the covers shall deflect by more than 1/200 of the shortest span of the section. e)
Supports for Covers
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The covers are to be securely fixed to the tank walls. The fixing arrangements shall be designed in detail by the Contractor and shall be capable of withstanding all stresses and disturbing forces which may result from the design loading conditions as well as uplift forces which may occur due to the flooding of treatment processes. The extent to which uplift forces need to be allowed for shall be considered for each cover individually. The fixing arrangements shall be capable of accommodating the maximum relative movement which may occur because of the loading on the covers and variations in environmental conditions such as temperature and humidity. Where covers are to be installed onto existing structures the Contractor shall establish, prior to installation of the covers, that those portions of the existing walls which are to support the covers are adequately level and sound to accept the Contractor’s proposed fixing arrangements. f)
Environmental Conditions
The covers shall be resistant to the environmental conditions which may be encountered and shall show no deterioration of material or leakage after prolonged exposure to these conditions. The covers will be placed over tanks, vessels and channels which contain sewage and sludge, and the covers shall be suitable for continuous exposure to sewage vapours. High humidity levels will occur beneath the covers and the covers shall be suitable for use in conditions of 100% humidity. The sewage is a mixture of domestic wastewater and industrial wastewater. Under some conditions sewage will release hydrogen sulphide, and the covers shall be designed to withstand hydrogen sulphide concentrations of up to 100 parts per million (by weight). Other chemicals will be present in the sewage and the covers shall be resistant to a wide range of such substances. The upper surfaces of the covers may be exposed to the atmosphere and such covers shall therefore be resistant to the high levels of humidity, rainfall, UV radiation and to the elevated temperatures which will result from the strong sunlight. The covers shall be suitable in all respects for use in the tropical climatic conditions which prevail in Malaysia. g)
Design Features
All cover sections shall include stainless steel lifting eyes which shall allow the sections of cover to be lifted in a stable and balanced manner. A minimum of three lifting eyes shall be provided in each section of cover. The cover shape of the cover shall be proposed by the Contractor for the approval of the S.O. They shall be generally of low profile to minimise the volume of air contained beneath the cover. Covers shall generally be designed so that they may be removed, either in single sections, in two or more sections joined together or in their entirety. The design of covers shall be such that they may be removed and replaced easily without deformation and without affecting the air tightness of the covers. The covers shall be designed to avoid the collection of rainwater, and all parts of the cover shall be curved in cross-section or shall have a slope of at least 1/100. The profile of the covers shall be designed so that rainwater drains from the covers towards the periphery of the tank. The covers shall incorporate rainfall collection facilities adequate to accept the flows which will result from the continuous discharge of the design rainfall rate 215mm/hr. The covers shall be designed so that rainwater drains to the edge and out of the tank. Rainwater downpipes shall incorporate a trapped floating ball type of seal, as generally indicated on the drawings, to prevent the emission of foul air when rainwater is not being discharged. An alternative mechanism for the prevention of foul air from the rainwater downpipes may be proposed by the Contractor. Cover designs shall be consistent in appearance with respect to colour; surface finish and, as far as possible, profile and shall be submitted to the S.O. for approval. Typical Civil and Structural Engineering Specification for Sewerage Works Issue 01 / Rev 0 August 2008
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Section 12 - Miscellaneous
The covers shall be provided with inspection and access openings generally as indicated on the drawings. Hatches shall either be of the hinged-type, of the sliding-type, or of the removable-type. The hatches shall be air-tight when closed, and shall be provided with latches or screw-type fittings to ensure that they do not rely on self-weight to remain closed. It shall be possible for one person to remove the hatch easily and without assistance. Hatches of the hinged type shall be hinged to be opened flat. Detailed proposals for these openings and hatches shall be submitted to the S.O. for approval. The cover profile proposed by the Contractor shall allow easy personnel access to these access openings from adjacent walkways and steps, stairways or ladders shall be provided where necessary. The covers shall contain various items of equipment and ducting associated with the ventilation and odour control facilities, including air inlet louvers, air pressure relief devices vacuum relief valves and foul air ducting, as required for the efficient and safe operation of the covers and ventilation system. The covers shall be designed to accommodate these items insuch a way that the items may be readily removed without damaging the covers. Where mechanical equipment will be enclosed beneath covers, provision shall be made in the design for the maintenance of this equipment. This will generally be achieved by the use of removable sections of cover. Some cover sections shall contain instrumentation equipment such as level sensors and dissolved oxygen probes. Where these are required the covers shall incorporate flanges for the installation of these instruments. Specific requirements for handles, fixings, locks, hinges, returns, moulded architraves, seals, louvers and screw caps shall be provided where necessary. The covers shall be securely fixed to the existing tanks. The fixings shall be designed be the Contractor for the S.O.’s approval. Where necessary the design of the fixings shall make allowance for relative movement between the cover and the fixing which may result from any reason such as deformation of the covers caused by the loading and by environmental conditions such as temperature and humidity. h)
Laminate Design
The laminate shall be designed by the Contractor to be suitable in all respects for the proposed purpose. It shall have adequate chemical resistance to withstand the environmental conditions to which it will be exposed, and shall have adequate strength and stiffness to withstand the design loadings identified above and the impact loadings specified below. The upper surface of the covers shall have an applied non-slip finish within 1200mm of all access openings, other fittings such as air inlets, instrumentation fixings and pressure relief valves, and elsewhere as indicated on the drawings. The non-slip finish shall also be applied in a 1200mm wide strip between each such access opening or fitting and an adjacent walkway. The upper layer of laminate shall be a resin-rich layer containing at least 90% resin, into which shall be incorporated a UV absorber and light stabiliser. All layers of laminate shall use the same approved isopthalic resin into which shall be incorporated a light stabiliser.
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Section 12 - Miscellaneous
All laminates shall be of solid construction with void construction with void content not exceeding 3% anywhere except within polyurethane foam inserts. All laminates shall be at least 5mm thick. All laminates shall maintain structural continuity through staggered reinforcement overlaps of at least 25mm everywhere. All exposed internal and external surfaces shall have a resin-rich surface layer consisting of either : A resin gel coat between 0.75 and 1.25 mm thick applied to the mould surface prior to the main structural layers; or A resin flow coat between 0.25 and 0.50 mm thick applied to the free surface of the laminate. The resin gel coat and the resin flow coat shall contain a continuous layer of surface tissue thoroughly impregnated with resin. Laminate properties shall be determined by carrying out mechanical tests on representative samples using the appropriate test method in BS 2782. Minimum strength values for design process shall be determined by statistical analysis of test results and calculation of the value which gives 95% confidence of exceedance. Test results and the analysis used to determine the design strength of the laminate shall be submitted to the S.O. i)
Lightning Protection
Covers at risk of damage by lightning shall be provided with lightning protection facilities, which shall be designed by the Contractor in such a way that they do not impede access to or the operation of any of the hatches or items of equipment installed on the covers. Lightning protection facilities shall be designed and installed in accordance with the requirements of BS EN 62305-1. The lightning protection system shall be extended to protect the ventilation ductwork, access platforms and other structures installed and subject to possible damage from lightning. The electrical resistance of the covers shall be greater than 20 megohms.
12.19.3 Materials a)
General
All materials used in the fabrication of the covers, supports, fixings, fittings and as sealants shall be compatible with each other, and shall be suitable for their proposed application. All FRP components shall be constructed entirely from those materials listed in this section. There shall be no other materials, such as metal or timber encapsulated within the FRP.
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b)
Resins
Covers shall be manufactured using a premium grade, high molecular weight isophthalic polyester resin in accordance with the requirements of BS 3532. No base acid other than isophthalic acid shall be present. The proposed resin shall be approved by the S.O. All resins shall be of the fire resistant type where covers are to be contained within outer structures. Other covers which are open to the atmosphere shall not be of the fire resistant type. Fire resistant resins shall achieve a flame spread rating of 25 or less to ASTM E 84, Class 1. Properties of the liquid resin shall meet the following requirements: Property Specific gravity @ 25oC Acid value Volatile content
Unit -
Value 1.05 – 1.15
mgKOH/g %
15 – 20 55 – 60
Test method BS 2782:19762 BS 2782:1976 BS 2782:1976
Properties of unreinforced resin costings shall meet the following requirements: Property Specific gravity Barcoll hardness Deflection temperature (under load) Tensile modulus Elongation at break c)
Unit o C
Value 1.2 – 1.3 > 45 85
MPa %
> 3500 > 2.5
Test method BS 2782: BS 2782: BS 2782:
BS 2782: BS 2782:
Reinforcement
All reinforcement material shall be manufactured from E glass fibres except for surface tissues which shall be manufactured from C glass fibres or spun bonded polyester. Reinforcing material shall meet the following requirements: Type Chopped strand mat Continuous strand mat Woven roving Unidirectional cloth Continuous roving Surface tissue d)
Maximum weight 600 g/m3 600 g/m3 600 g/m3 800 g/m3 Not applicable 100 g/m3
Specification BS EN 14118 BS EN 14118 where applicable BS 3749 BS 3749 BS EN 14020
Additives
Other than reinforcing material, only those materials listed below may be added to the resin. In all cases they shall be thoroughly mixed in an adequate precautions shall be taken to prevent settling out. Material
Form
Additive
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Maximum 12-20
Section 12 - Miscellaneous
Pigment Accelerator
Catalyst
Thixotrope
Release agent UV adsorber Light stabiliser e)
Polyester paste Liquid
Liquid
Paste Powder Paste
Cobalt naphthanate Cobalt octoate t-butyl per 2 ethyl hexanoate di-methyl aniline di-ethyl aniline Methyl ethyl ketone peroxide ) Acetyl acetone peroxide t-butyl peris } enonanoate } Benzoyl peroxide Finely divided fumed silica } Fumed silica in Polyester
} } } } } } }
content (by weight) 45%
content (by weight) 8%
0%
0.5% of 1% 0.5% of 1% 2% 0.5% 0.5% 3%
}
3% 2%
1% } }
4% of 50% 4%
)
15%
Liquid
0%
1%
Liquid
0.2%
0.5%
Liquid
0.2%
0.5%
Other Materials
All supports for FRP covers shall be of FRP, aluminium Grade 7075-T73 or stainless steel Grade 304 of BS 970: Part 1. All ferrous fixing bolts, nuts and washers, and all ferrous hinges, handles and latches shall be of stainless steel Grade 316 of BS 970: Part 1. Sealing gaskets shall be of neoprene or silicone. Polyurethane foam may be used as a non-structural former for the construction of box sections.
12.19.4 Workmanship a)
Premises for Fabrication of Covers
The FRP covers shall be fabricated under cover in premises dedicated to the manufacture of FRP products. The premises shall have a hard concrete or tiled floor, shall be free of dust and shall be well illuminated. The covers shall be manufactured under controlled environmental conditions, such as temperature, humidity and air movement, compatible with the satisfactory productions of FRP elements.
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b)
Storage of Materials
All materials to be used for the fabrication of covers shall be clearly labelled with the product name, date of manufacture, use-by date or shelf-life and instructions for use from the material supplier. Materials shall be stored in a dedicated covered area in accordance with the material supplier’s instructions. Raw materials shall at all times be protected from rain and from direct sunlight. A detailed record of the date, quantity and type of all deliveries of materials shall be maintained, together with a record of when materials have been used. All delivery notes for materials shall be retained and made available for inspection when required by the S.O. c)
Cover Manufacture
Cover components shall be manufactured by one or more of the following processes: -
contact moulding with woven or mat reinforcement; low pressure press moulding; resin transfer moulding; pultrusion; centrifugal casting.
Cover components shall not be manufactured by the spray-up process. The cover components shall be manufactured in accordance with the requirements of BS 4994: Clause 26, 27 and 28. The Contractor’s proposed laminating procedures and operators shall be approved by the S.O. in accordance with the requirements of BS 4994: Clause 36. The manufacture of an individual cover component by contact moulding shall be continuous to ensure that the laminate has not fully cured before the addition of subsequent layers of laminate. d)
Curing
After manufacture each component shall be finally cured. This shall be effected by oven curing to either 60 oC for six hours or 80 oC for five hours. The Contractor may propose an alternative curing regime, which may be approved by the S.O. No component shall be removed from its mould until it has achieved a Barcoll hardness of at least 15 (at 20 oC). All components shall achieve a Barcoll hardness of at least 30 within 5 days of removal from the mould. e)
Storage of Covers
Once cover segments have been fully cured they shall be stored carefully prior to use to ensure that they are not damaged. The method and location of the storage shall be approved by the S.O. f)
Transport of Covers
Cover components shall be transported with care to ensure that they are not damaged in transit. The Contractor shall be responsible for making whatever arrangements are necessary for the transport of large or long cover elements.
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g)
Cover Installation
The method of installation of the covers shall be proposed by the Contractor for the S.O.’s approval. Where cover sections or complete covers are to be lifted by crane due allowance shall be made in the design of the covers, and the Contractor shall, if required by the S.O., submit calculations to demonstrate that permissible stresses or strains in the covers will not be exceeded. Chain and wire rope shall not be in direct contact with the FRP when cover sections are being lifted. Covers shall be securely fixed to the supports generally as indicated on the drawings. The Contractor shall carry out any necessary work to prepare the supports for the covers prior to installation of the covers. All tanks, channels and chambers shall be cleared of any liquid. Sludge, grit, scum or other debris and the tank walls and floors shall be thoroughly cleaned prior to installation of the covers. All vertical concrete surfaces shall be painted with a high build pitch/epoxy paint as specified prior to installation of the covers. All mechanical equipment shall be inspected repaired and repainted prior to installation of the covers. h)
Repairs
Where cover elements contain defects which exceed those permitted by the specification or where cover elements have been damaged during transport, storage or installation the Contractor may propose to repair the defective or damaged section subject to the approval of the S.O. Such repairs shall completely reinstate the full structural strength and rigidity, and the full chemical resistance of the element. Such repairs shall only be undertaken if approved by the S.O., who may require additional tests to confirm that defects and damage have been adequately repaired. Repairs shall not detract from the appearance of the covers and where repairs have been permitted by the S.O. the Contractor shall take precautions to ensure that the appearance of the repaired sections closely matches that of the other sections of the covers. The S.O. may refuse to accept repairs on the grounds of appearance, notwithstanding that the full structural integrity and chemical resistance of the undamaged section of the covers has been reinstated.
12.19.5 Inspection and Testing a)
General
In general material records, quality control tests and quality control records shall be kept or undertaken in accordance with the requirements of BS 4994: 1987 where these requirements are relevant to the manufacture of tank covers. These tests shall include the following principle stages: i.
inspection of the workshop conditions where the Contractor proposes to undertake the workshop;
ii.
inspection of work’s records relating to the control and issue of materials, resin mixing, etc, for each cover;
iii.
identification of the materials of construction and their storage conditions;
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iv.
approval of laminating procedures and tests for operators and check of validating documents;
v.
examination of hand lay-up, winding and jointing of resin-glass laminates;
vi.
examination of any repairs carried out during construction;
vii.
verification of the cure of laminates;
viii.
examination on completion of construction as given below for factory testing and field testing.
When additional inspections by the S.O. are deemed to be necessary because of unsatisfactory results of the above tests, the costs of these additional inspections shall be borne by the Contractor. Where material samples are found to have failed any of the specified tests the batch from which the sample has been taken shall be rejected and shall not be incorporated into the permanent works. Where cover components are found to have failed any of the specified tests they shall either be repaired if this is permitted under the specification and subjected to further tests, or shall be rejected. Rejected components shall not be incorporated into the permanent works. The S.O. may reject other cover components following the failure of a cover component, or may require additional tests to establish their acceptability. b)
Factory Testing
Test certificates shall be provided by the Contractor showing that the Barcoll hardness of the cured resin used in the manufacture of the covers is greater than or equal to 45. E glass fibre chopped strand mat shall be subjected to the test requirements of BS EN 14118 Table 1. Manufacturer’s test certificates for the mat proposed by the Contractor shall be forwarded to the S.O. prior to approval of the Contractor’s laminate design. Woven roving fabrics of E glass fibre shall be subjected to the test requirements of BS 3749 Appendices A, B and C. Manufacturer’s test certificates for the fabric proposed by the Contractor shall be forwarded to the S.O. prior to approval of the Contractor’s laminate design. Production samples for mechanical tests on laminates shall be produced and tested in accordance with the requirements of BS 4994 Clause 37. The following visual inspections shall be carried out by the Contractor and may be witnessed by the S.O. The results of the inspections shall be reported to the S.O. in a standard format which has been approved by the S.O. i.
Crazing. There shall be no crazing of the gel coats or resin-rich layers.
ii.
Resin-dry areas. On moulded and corrosion resistant surfaces such areas may be accepted provided they do not exceed 6mm in diameter and are subsequently made good. Not more than 0.5% of the surface area shall be so affected.
iii.
Other surfaces. All resin-dry areas shall be repaired.
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iv.
Mouded and corrosion resistant surfaces. Scratches not exceeding 0.2mm deep may be accepted without repair provided that no glass fibres are exposed. The total extent of the scratching shall not exceed 200mm length per square metre or, where small scratches are grouped together, the affected area shall not exceed 1% of the surface area. No repairs are acceptable.
v.
Other surfaces. Scratches not exceeding 0.5mm deep may be accepted without repair provided that no glass fibres are exposed. Scratches more than 0.5mm deep may be repaired provided that the structural integrity of the laminate is not impaired.
vi.
Moulded and corrosion resistant surfaces. Voids not exceeding 3mm diameter and 0.5mm deep may be repaired provided that the voids do not occur in discrete clusters and the sum of the areas of clusters does not exceed 0.5% of the total moulded area.
vii.
Other surfaces. Voids may be repaired provided that they do not exceed 1.5mm deep and no more than 3% of the surface area is affected.
viii.
There shall be no apparent cracking of either the moulded and corrosion resistant surfaces or other surfaces. There shall be no star cracking.
ix.
There shall be no fibres protruding from the surface of the laminates. Wrinkles and undulations shall be gradual and the surface shall be continuous at such locations. Such defects shall not appear extensively on a single moulding nor shall they be repeated throughout a production run.
x.
There shall be no visible extraneous inclusions other than permitted fillers or aggregates.
xi.
There shall be no visible delamination.
xii.
All surfaces shall have a consistent colour throughout.
xiii.
All drilled and cut edges shall be smooth, even and substantially free from chips, burrs, sharp corners or exposed fibre strands.
Where repairs are permitted they shall be undertaken using a method which has been approved by the S.O. The electrical resistance of the covers shall be tested as follows: -
cover parallel to the plane of the sheet; cover normal to the plane of the sheet.
All tests shall be carried out and witnessed by the S.O. c)
Field Tests
The following tests shall be undertaken on a sample segment of each design of cover; i.
a soft body impact due to a 50 kg sandbag dropped form a height of 2 metres;
ii.
a hard body impact due to a 1 kg steel ball dropped from a height of 1 metre.
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The sample segments shall be selected by the S.O. The above two tests shall be carried out at intervals of 1 metre along the axis of the greatest span of each sample. Failure of the laminate shall be determined by observing star-crazing (if any) on the reverse side or front face of the laminate and determining the depth of penetration of such a crack. In respect of the sample laminates, dye shall be impregnated into the cracks and a section shall be cut through the laminate at the point of fracture to determine the depth of adsorption. Failure under these dynamic impact tests shall, unless otherwise agreed, be construed if the depth of cracking at the impact points exceed 25% of the total laminate thickness. Where failure of the samples has been observed the Contractor shall resubmit the laminate design to the S.O. and subject it to test again. Where failure of the structural segments has been observed the Contractor shall rectify the situation by either replacement or an approved repair and subject the segments to test again. When required by the S.O. a trial erection of the cover components shall be undertaken to demonstrate that the cover components fit together accurately without the use of force to align components. Installation of the covers shall not proceed unless a trial erection has been completed successfully where one is required by the S.O. The following visual tests as required for factory testing shall be carried out on site prior to and after installation of each cover in accordance with the relevant standards: i)
crazing;
ii)
scratches;
iii)
cracking;
iv)
delamination
v)
drilled and cut edges.
An air-tightness test shall be carried out on completion of the installation of each cover. The air inlets to the space beneath the cover shall be closed off and a small compressor shall be operated in a controlled manner to establish a pressure differential across the cover. The cover shall be deemed to be adequately air-tight if the design operating pressure differential of 0.15 kN/m3 produces an air flow rate into the covers of less than 10% of the design operating ventilation rate. A similar test shall be undertaken to determine the adequacy of the structural design of the covers. Deflections of the covers shall be measured with a pressure differential across the covers of 1.25 kN/m3 and shall be compared with calculated values of deflection used in the design. The covers shall be deemed to be acceptable if the anticipated deflection is not exceeded during the test. The Contractor may propose an alternative equivalent method of demonstrating the structural adequacy of the covers. The air-tightness test and the structural adequacy test shall generally be undertaken in accordance with the requirements of BS 4994 Clauses 39.5 and 39.6 using the test pressure given above.
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Throughout the air-tightness test, and the structural adequacy test, care shall be taken to ensure that the internal pressure beneath the covers is reduced in a controlled and measured manner and at no time shall the total maximum loading exceed 1.25 kN/m3. The Contractor’s proposed procedures for undertaking these tests shall be submitted in advance to the S.O. The tests shall be carried out in strict accordance with these procedures once they have been approved. The results of these test shall be recorded and reported to the S.O. The format of these records and report shall be agreed in advance as part of the Contractor’s proposed procedures.
12.19.6 Water Supply System a)
General
The Contractor shall design the water supply system for the supply of water to the sewage treatment works for the operation and maintenance of the sewage treatment plant and for the potable and domestic water supplies which are required for the treatment works including the administration building and other buildings as specified. The water supply system shall consist of a high-pressure water supply system and service water system. The system to be provided shall include filling of chemical preparation tanks, chemical dosing, high pressure water supply for fire-fighting, motive water supply for chlorination, water for hosing down tanks, water for odour removal system, water for flushing and cleaning of sludge pipework, potable water for all water tanks, pump station, lawn water tap and for the laboratory. The water supply system as envisaged shall be referred to the drawings. b)
High Pressure Water Supply System
At the branch connection on the treated water delivery main, pipework including a flow meter, a pressure-reducing valve with a downstream pressure relief valve and pressure gauge shall be installed, to provide a high-pressure water supply at a controlled pressure. The high-pressure water supply main shall be laid from pipework to form a ring main around the treatment works. Interconnections shall be provided along the main to supply high-pressure water to the various sections of the Works. Branches shall be provided along the main loop to points at the structures within the sewage treatment works as shown the drawings. Each branch from the high pressure water supply main shall have an isolating valve and suitable pressure reducing valve. Branches with isolating valves shall be provided for the supplies for fire-fighting within buildings and with suitable pressure reducing valves for the domestic water supplies at the administration building, chemical building, inlet pumping station and other buildings that require water. Branches shall be provided elsewhere where a supply of high pressure water is required. Hydrants shall be installed along the route of the high pressure main; the hydrant locations, capacities and outlets shall conform to the requirements of Jabatan Bomba. c)
Design Criteria
The operating pressure in the high pressure water supply system shall not be less than 60m head at any point in the system. Particular attention shall be paid to the end points in the high pressure system to ensure that the operating head is not less than 60m head. The C-value to be adopted for the design shall not be more than 100. The high pressure system pipework shall be laid and tested to 100m head. The diameter of the main pipe to the ring main shall not be less than 200mm dia. The Sub-Contractor shall design and upgrade the pipe sizes as required for proper and efficient operation at no additional cost to the Contract.
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Pipe diameters for outside firefighting system shall not be less than 100mm. The maximum spacing between fire hydrants and the distance to nearest buildings or structures shall comply with the requirements of Jabatan Bomba. The quantity of water to be available from three fire hydrants shall be 3m3/min at not less than 40m head; this shall be in addition to the quantity of water required for the high pressure injector motive water supplies. Pipe diameters of the main service water supply system from the service water tank shall be amply sized to permit maximum flows under service conditions, and shall not be less than 100mm diameter for supplies to the chemical building areas and not less than 25mm diameter for service water supplies to the chlorine building. The diameter of the branch pipes to the administration building control buildings shall be not less than 50mm dia. d)
Pipework
All pipes shall be laid underground generally with 1 m minimum cover. Valves and air valves shall be provided in drained chambers where required. Any vulnerable pipework shall be suitably protected. Valved washout branches with effluent drain systems shall be provided at low points in the main system to permit sections to be emptied.
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