Technical Proposal For Detailed Engineer

 

PROPOSED TECHNICAL TECHNICAL APPROACH & METHODOLOGY

a. Technical Ap Approach proach & Methodolo Methodologies gies 2.1

Introduction

The Consultancy Services required for this Project, will be provided by Multi Dimension for Engineering Consultancy (MD). Our approach to this Project is based on divi dividi ding ng the the ta task sk in into to Ter m o f R e f e r e n c e s . The appr approa oach ch,, will will now now be  presented in some detail hereinafter . 2.2

Consultancy Services

2.2.1 Services during Phase I

The Preliminary site action plan and desk study will cover the following items for this road project: - Investigation of alternative alignment - Climate, geology and vegetation study. - Mapping and Aerial Photography - Hydrology and drainage Investigation. - Preliminary soil investigation. - Preliminary design (geometric and pavement design). - Environmental and social impact assessments. During this phase, the Consultant will submit inception report and interim report. 2.2.2 Services during Phase II

Base Ba sedd oonn tthe he rres esul ults ts ooff th thee pre limin li min ar aryy a nd sit e i nve sti gat ion st stud udyy carried out in Phase I, the detailed engineering design will be carried out as outlined below:-

Topographical Survey Survey of water courses Hydrological and geological surveys Soils and materials survey Geometric design

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Pavement design Bidding documents for construction 1

 

2.3

Technical App Appro roach ach and Methodo Methodologi logies es

2.3.1

Topographical opographi cal Survey:

2.3.1.1 Introduction:

The procedure to carry on the topographical surveys is shown in the following sections. 2.3.1.2 The selection of the best route alignment:

First to choose the best route alignment we will first review the Google earth image and find the best area for the route. This will reduce cost and time. Then the  preliminary road area will be proposed. After that and using the preliminary proposal data the site will be visited to check the route and to adopt the final road area. After  adopting the final road area the field survey will start. (During this step we suggest that representative of the Roads and Bridge Corporation to be attending and to approve the proposed road area on site)

2.3.1.3 The field Survey: i.  The installation of  bench marks: 3 benchmark  will  be installed  as  follows:

- Additional benchmark will be installed at the start of road, middle of road and at the end of the road. The proposed benchmark will be established by inserting a 15 mm diameter inserted in the ground, with a 30 cm section above the ground covered with a cube of concrete (30x30x30 cm). ii. 

The Reduced  level  of  benchmarks:

In order  to get  an accurate reduced  level  for the benchmarks their reduced levels will be  obtained  using  spirit  leveling  (using  automatic  levels).   A  double  leveling procedure  will  be  carried  out  to  check  the  miss  closure  (error  of   observation).  The maximum accepted  miss closure (e) will be computed according to the formulae;

e = 10 √ k mm. which is quoted for the accuracy of engineers levels in BS5606. Where k is the length of circuit in Km. - The circuit will be computed and adjusted to obtain the optimum reduced levels for  the benchmarks.

 

iii. 

Reading cross section/levels of  the ground  and  oset  levels:

- Using the established established Benchmarks as a reference the following observations will be carried out using GPS Real Re al Time observation techniques: - Cross – Sections /levels of the ground will be observed at 50m. intervals and at abrupt changes of the ground along the entire length of the road and locations of  alignment. The width of the offset levels will be read according to the site conditions iv iv.. 

Detailed  Surveys:

A detailed survey will be also carried out to obtain the coordinates and dimensions of the existing utilities and land uses in the road area using GPS Real Time techniques. Also satellite images (such as Google earth) or any other available images will be also reviewed to help in surveying the utilities and land uses. Mixing the two data (field observation data and satellite images) will help in better assessment of the existing utilities and structures within the road right of way. 2.3.1.4 Office activities (Data Processing and Computations): Computations):

-The field data obtained will be processed using Trimble Business center soft ware, and Excel soft ware. 2.3.1.5 Vehicles and Equipment:

ITEM GPS Real Time 4WD Car Automatic Level Pick up Car

Number 2 receivers 1 2 2

Days 75 90 45 45

2.3.1.6 Manpower: ITEM

Senior Surveyor Surveyor (Real Time Obs. and Senior Surveyo eyor Ass.) Ass. Surveyor Surveyor (leveling) Skilled Labor (GPS Tech.) Labor (Benchmarks Construction) Labor (4Staff holders and two ass.) Driver Driver

No.

Days

2 2 2 3 2 2 4 2 3

90 75 75 45 75 21 45 75 45

 

2.3.1.7 Work Plan: The topographical survey services will be executed as follows:

1- Satellite image review and preliminary preliminar y route alignment proposal – will be completed in five days. 1 A field visit to ccheck heck the route ali alignment gnment - To be completed in 7 days 2- Benchmark installation which will start after the end of the reconnaissance survey and will be completed in 21 days. 3 – Benchmarks Leveling. The benchmark leveling will start after three days from the start of benchmarks installation. Three leveling teams will carry on the leveling using automatic spirit levels. The leveling will be completed c ompleted in 45 days. 3- The topographical survey and detailed survey. This activity will start after 7 days from the start of the Benchmarks leveling. leveli ng. The activity will be completed in 75 days. 4- Data processing and computations of coordinates and elevations. This activity will start 7 days after the end of benchmarks leveling and will be completed 5 days after  the end of the topographical survey activity. But every 10 km. completed will be submitted immediately for the geometric design purposes. The total time needed to complete the above activities is 90 days.

 

2.3.2

Hydrological Investigations

2.3.2.1 Study Objective

The main objective of this investi investigation gation is to prepa prepare re an effective hydrologic and hydraulic hydrau lic design of the road drainage system. Informatio Informationn to be gathered on the hydrology of the study region, intersecting the road, their hydrologic and hydraulic characteristics will be used to calculate the most important design parameter which is the peak discharge. Accordingly, the type and size of the drainage structure will be determined. The methodology to be adopted will involve the following steps 2.3.2.2 Review of previous studies

Previous studies on road design or similar water related studies in the area will be gathered and all the relevant information will be extracted and entered a database for  the study. 2.3.2.3 Field investigations through site visits

A number of site visits will be made along the road route. Types of soil, vegetation, cross sections, water marks, catchment characteristics and all factors that influence runoff and water levels will be noted. Existing drainage structures will also be surveyed and interviews of officials and local inhabitants will be made regarding flooding history of the significant and other related issues.. 2.3.2.4 Data collection

This will include collection of topographic maps, drainage maps, and satellite imageries as well as collection of rainfall data for relevant rainfall stations. 2.3.2.5 Collection and analysis of rainfall data

Rainfall data for the rainfall stations in the study area will be collected from the Sudan meteorological department. The data will be screened and checked for consistency and any missing data will be filled using appropriate techniques. Frequency analysis will then be performed to develop the Intensity-Duration Frequency Curves (IDF).

 

2.3.2.6 Hydrologic analysis for estimating design discharges

The discharges will be estimated using the rational model .This method is most commonly used method where the catchment areas and other information are available. According to the rational model, the peak discharge Qp is given by: Qp = C.A.I / 3.6 Where C = runoff coefficient depending as the type ooff soil and vegetation cover cover.. A = Catchment area (Km2) determined from satellite data I = Design rainfall intensity(mm/h) during the time of concentration The maximum runoff rate in a Catchment is reached when all parts of the watershed are contributing to the outflow. This happens when the time of concentration, the time after which the runoff rate equals the excess rainfall rate, is reached. 2.3.2.7 Design of drainage structures

Using the Rational method the peak discharge for the appropriate return ret urn period (normally 50 years) will be estimated with catchment areas of Wadis being obtained from satellite imageries or alternatively from Google Earth. Alternative models will also be applied to estimate design discharges such as the Manning formula. Once the design discharge is estimated then the appropriate type of culvert will be recommended. The following possibilities will be considered   

Pipe culverts Box culverts Bridges Guidelines for locating the culverts during execution will be given. 2.3.2.8 Design of Protection Works

For erosion control and protection of drainage structures and road embankment, the conceptt of incip concep incipient ient motion will be used for rock rip rappin rapping. g. The critical shear  equation will be used to determine the rock sizes 2.3.2.9 Study period

3 months including: Site visits Data collection and cost Design and reporting

 

2.3.3 Soil and Material Survey 2.3.5.1 Scope of Work 

The soil and materials survey will include the following: Field work will comprise of excavating pit-holes for the natural subgrade beside the roadway alignment. Soil survey of the locally occurring construction materials is essential to indicate their  quality, locations and to estimate the quantities available at each site. Accordingly  borrow pits will be excavated at certain locations in the road site. Laboratory tests will be carried out on representative samples taken from the borrow  pits. Possible problems arising from the use of proposed materials in the area under study will be assessed, quantified and appropriate counter measures will be recommended.

2.3.5.2 Field Work  i. 

Excavating  Pits

The field investigation will start with excavating pit-holes in the area of the road sites. The pit-holes generally will be excavated at intervals not more than two kilometer  length of the roadway or if there is any variation in the soil, to cover most of the natural subgrade areas. For the locally occurring construction materials some borrow  pits will be excavated in certain locations in the area under study. The locations of  these borrow pits will be decided after the site investigation. The pit-holes and borrow  pits will be excavated to a depth not less than 1.5 m and each pit of one meter by one meter cross sectional area. Disturbed soils samples will be taken from these pits to represent the roads' subgrade soils and the local construction materials to be used. These soil samples were kept in  plastic bags, labeled and transported to the Laboratory for visual inspection and testing. ii. 

Soil Investigation

Subsoil exploration is to be carried out at the locations of the existing or proposed  bridges and Irish crossing at khors and valleys. At these sites certain numbers of  9

 

 boreholes are to be drilled to satisfactory depths and field tests are performed if  required. 2.3.5.3 Laboratory Testing

The Laboratory investigation is comprised of performing some tests on disturbed soil samples that are taken from the roads site. The testing procedures will be followed are in ge gene neral ral confo conform rman ance ce with with thos thosee reco recomme mmend nded ed in BS 1377 1377 and and ASTM ASTM.. The The laboratory tests will be performed included the following:I.  Soil Tests

The soil tests include: Sieve analysis, Atterberg limits, modified compaction and Soaked CBR. These tests to be performed for the pit-holes at intervals of about 2000 meter (115 sections) and 30 borrow pits for the locally occurring construction materials. In the locations of the bridges and Irish crossing almost 5 locations where two boreholes of 10 to 15 meter depth will be drilled, the soil gradation and limits tests are curried out at one interval of the boreholes while the shear and consolidation tests are performed for specified soil layers. i. 

Concrete Tests

For concrete: Compressive strength of concrete cubes, Mix design. 2.3.5.4 Tests Quantity

The laboratory and field testing for all the construction materials are listed in the table  below with their quantities as follows:  No

Test

Quant.

1 2

Atterberg Limits & Gradation Tests Modified Compaction

300 140

3

Soaked CBR

140

4

Shear Strength

5

Concrete Mix Design

6

Boreholes drilling

7

Pit-holes excavation

8

Borrow pits excavation

70 1 15 100 30

 

2.3.5.5 Technical Staff 

The technical staff required to carry the laboratory and field testing for this project for a period about five months as follows: 

Senior Material Engineer



Three  Junior engineer

 

Six Technicians



two drivers

9 skilled & 5 unskilled labours

 No 1 2 3 4 5 6

Staff r Three Junior engineer Six Technicians 9 Skilled labours 5 Unskilled labours two drivers

Number of Months 8 6 6 5 5 8

 

2.3.4 Geometric Design

Geometric design is the process whereby the layout of the road in the terrain is designed to meet the needs of the road users. The principal geometric features are the road cross-section and horizontal and vertical alignment. The use of geometric design standards standa rds fulfills three inter-re inter-related lated objectives. Firstly, standards are intend intended ed to  provide minimum levels of safety and comfort for drivers by the provision of  adequate sight distances, coefficients of friction and road space for vehicle maneuvers; secondly, they provide the framework for economic design; and, thirdly, they ensure a consistency of alignment. The design standards adopted must take into account the environmental road conditions, traffic characteristics, c haracteristics, and driver behavior. Based on traffic, axle load, roads safety audit review and according to TOR  requirements the data will be fed into the design software (Land Desk top 2009) to select the suitable design elements those comply with design speed of 120 km/h. The check will be automatically based on AASHTO 2001 Geometric Design Policy after  the assignment of some design elements. The design process will be according to the following flow chart. Generally the design criteria considered during design and alignment of the road will  be: 

Right of way and Road way features.



Vehicular characteristics.



Traffic pattern.

 

 Number of lanes, widths and shoulder type and width. Design speed.



Maximum and minimum grade.



Maximum superelevation.



Sight distances



Vertical and horizontal curves characteristics.



 Normal crown of surface

 

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2.3.5 Pavement Design 2.3.5.1 Introduction

The pavement design process will be through the following steps:   

Estimation of Equivalent Standard Ale Loads (ESAL). Determination of design subgrade strength value (CBR).

Interpolation of data and different studies and revision of the determined thickness from economical point of view.

2.3.5.2 Determination of Cumulative Equivalent Standard Axles:

The equivalence factors for each of the wheel loads measured during the axle load survey will be determined using the equation given below to obtain the equivalence factors for vehicle axles. The factors for the axles are totaled to give the equivalence factor for each of the vehicles. For vehicles with multiple axles i e. tandems, triples etc., each axle in the multiple group is considered separately. The mean equivalence equivalence factor for each type or class of vehicle travelling in each direction will be determined. Vehicle classes are usually defined by the number and type of axles.

Taking into consideration the legal axle loads limits and restrictions shown on TOR of  this project the determination of the cumulative equivalent standard axles over the design life of the road, will be as follows: 

Determination of the daily traffic flow for each class of vehicle weighed using the results of the traffic survey and any other recent traffic count information that is available.



Determination of the average daily one-directional traffic flow for each class of vehicle.



Determination of the mean equivalence factor of each class of vehicle and for  each direction from the results of this axle load survey

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

The products of the cumulative one-directional traffic flows for each class of  vehicle over the design life of the road and the mean equivalence factor for  that class should then be calculated and added together to give the cumulative equivalent standard axle loading for each direction. The higher of the two directional values will be used for design.



The estimated ESAL determined from the axle and traffic surveys will be increased by the amount of the ESAL estimated to be diverted from other  roads to this highway and the converted traffic from other modes of transports in addition to the expected generated traffic expected from the industrial and land use development.



Then the estimated traffic ESAL in millions will be increased by the appropriate traffic growth factors from assigned opening year up to the design life (20 years).



This final ESAL will be used for determination of Traffic group (T) as recommend in Road Note 31 Structural Catalogue as shown in Table below.

2.3.5.3 Determining of Sub-grade Strength:

Havingg est Havin estimated imated the al alignmen ignmentt soi soill stren strength gth

usin usingg CBR CBR and classificatio classificationn test test

collected from the site and analyzed in the laboratory, the appropriate design CBR at 93 per cent or 95% of the maximum dry density achieved in Compaction Test using the 4.5 kg rammer can be determined for the t he road sections. The design Subgrade strength value will be determined using cumulative percentile curve as recommended in overseas road Note No. 31 and the strength (S) category will be determined accordingly using the following Table.

 

2.3.5.4 Determining of Deigned Thickness of Pavement

Based on the calculated ESAL Category (T) and the estimated subgrade strength (S), the pavement thickness will be determined using structural Catalogue taking in to consideratio consi derationn the resul results ts of road safety audit, material and existi existing ng pavement evaluation surveys. The final thickness also will be revised from economical point of  view. For the existing road based on the results of material survey, axle load and traffic studies and pavement thickness evaluation the current conditions of the existing layers will be assessed using an American Asphalt Institute overlay design method.

 

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2.3.6 Drainage Structures: 2.3.6.1 Introduction:

The consultant will review existing drainage structures and decide upon their  structural integrity integrit y and suitability for the new design. From topographic and hydrological data, structural system is to be designed and constructed to facilitate  passage of khors (streams) or drains under the road embankment. The consultant,  jointly with the hydrological expert will decide upon the most suitable hydrological structures required for the chosen alignment. 2.3.6.2 Methodology: Methodology:

A) Site V Visit isit and Field Inspection.

A site visit by the consultant is a must to determine on site information, such as: 

Structural conditions of the existing structures (Bridges, culverts & Irish crossings)



Visual inspection of existing bridges.



Topographical ffeatures. eatures.



Catchment area characteristics.



Khor (channel or stream) characteristics.



High-water information

B) Design of Drainage Structures:

I. Culverts: 

Depending on the amount of storm-water, reinforced concrete pipe or culverts of single, double or multiple cells may be required.



These culverts will be designed to resist all expected loading from earthwork, water pressure and superimposed loads.



Detailed design calculations will be carried out including design of wing walls and aprons.



Erosion protection work will be considered and fully described.

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

Recent international codes of practice will be adopted and this includes BS 8110, 811 0, BS 5400, ACI, EC2 & AASHTO specifications. II. Bridges:



The land topography or amount of storm water may require the provision of  other structural systems at certain places on the road routes.



These structural systems may be small span bridges of single or multiple spans.



Detailed design calculations for different bridge elements will be prepared.



The latest specifications of BS 8110, BS 5400, ACI, EC2 & AASHO are to be followed in the design of the drainage structures.

III. Extra Activities: The following extra activities will be included in the final report: 

Design of adequate foundation based on soil investigation data.



Design and description of erosion protection systems at any bridge or culverts site in collaboration with the hydrological consultant.



Preparation of tenders detailed drawings.



Preparation of technical specifications specificati ons and bill of quantities. IV. Standards &

Specifications: 

Design Methodologies: The methodologies to be employed for the design of  drainag dra inagee struct structure uress and erosio erosionn pro protecti tection on wil willl confor conform m to latest latest internationally accepted standards and specifications; this includes BS 8110, BS 5400, ACI, EC2 & AASHTO where appropriate. a ppropriate.



Earthquake-resistant Design: Earthquake resistant-design will be taken into consideration in the Design of bridges and culverts.

 

2.3 Project Program Schedule 2.3.1 Activities Activities Time - Schedule

The time-Schedule of activities, presented in Table (1) below, represents a realistic time-schedule related to the size of the Project. However, the actual time needed, for   phase I, I , will depend on the fe feasibility asibility studies actual volume of work required requir ed for this  project. The actual time of Phase II will be depending on the feasibility studies to  proceed for the detailed engineering design. The program specifying the Activity – Time Schedule and the distribution of  Consultants Personnel per Activity are presented in Table (2) & (3). 2.3.2 Reporting Schedule

The required following reports will be submitted according to the schedule shown in chart 1 below, the reports shall include: 1.

will be submitted within (6) weeks from the commencing date, it will include the outcomes of route alignment and the summary of other  Inception Report:

conducted activities and recommendations. 2.

Interim Report:

it will be submitted within (12) weeks from the commencement

date, describing the complet completed ed services, works in prog progress ress proposed recommendations. 3.

Draft bidding Documents:

upon competition of this stage three copies of the

following documents will be submitted within 24 weeks from the commencement date: a. Prequalification Document for C Contractor  ontractor   b. Bidding Documents: including instructions to bidders, condition of contracts  based on FIDIC 1999, Technical specifications, bills of quantities, drawing (plan-profile, structures details and others) and forms of bids and guarantees. c. Confidential Reports including Road Auditing, design, material and cost and time estimates reports. d. Final Documents: within (30) weeks from the commencement of of works we will submit eight copies of revised documents to the client.

 

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Abu Hamad – Karima Road Project  

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Chart 1: 1 : R EPORTS RT S S CHEDULE

STAGE 1 6 KEEKS

WEEK/ITEM 1

2

3

4

STAGE 2 12 WEEKS 5

6

7

8

9

10

11

STAGE 3 18 WEEKS 12

13

14

15

16

17

STAGE 4 24 WEEKS 18

19

20

21

22

23

STAGE 5 30 WEEKS 24

25

26

27

28

29

30

INCEPTION REPORT INTERM REPORT DRAFFT BEDDING DOCUMENTS -  -

PREQ PREQUA UALI LIFI FICA CA  TION DOCUMENTS. BIDD BIDDIN ING G  DOCUMENTS. CO CONF NFIDE IDENT NTIA IALL  DOCUMENTS

FINAL DOCUMENTS

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Abu Hamad – Karima Road Project

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4. Consultant Professional Staff 

To carry out the two phases of the project, the Consultant shall set up a technical and non-technical Staff. The Services shall be carried out by the personnel specified herein, for the respective  periods of time indicated therein. The Consultant shall not withdraw and/or replace any  person, specifically named herein, without the prior written co consent nsent of the Client. Wh Where ere the Consultant replaces any of his personnel, before the completion of the Services, any additional cost of such replacement shall be borne by the Consultant. MD & VOYANTS will provide logistics technical support services and other necessary resources and systems to allow their staff to operate effectively. 4.1 Project Professional Team 4.1.1

Technical Team Leader

A competent technical team leader will manage the consultancy team on the feasibility studies and the detailed engineering design. The Consultant Head-Office shall provide all necessary back-up services required by the team leader leader.. Such back-up will include the services of consultants, specialists, and other Head-Office Experts, for specific periods. Basically, the team leader shall be responsible for ensuring that the studies and design  progress is within approved approv ed time-schedule. 4.1.2 Consultants & Experts

These are the experts and specialists who participated in the previous phases of the Project. This group will carry out the feasibility studies and the detailed engineering design. The consultants and experts will be involved in this project include:1) Hydrologist Expert 2) Senior Transport Economist 3) Soil & Material Exper Expertt 4) Surveyor Expert 5) Senior Surveyor Engineer  24

 

6) Structural Expert 7) Senior Structural Engineer  8) Senior environmental Specialist 9) Contract/ Claims Expert 4.2 Proposed Project Personnel

The man-power required (Number, Specialization, Effective Time of Involvement and position in the Project) is indicated in Tables (2) and (3). The minimum number  of personnel, compatible with the scope of services specified in the TOR, has been considered in our Proposal. MD & VOYAN VOYANTS TS Key Project Personnel, proposed for this Project, Project, [Phase I (Feasibility Study) and Phase II (Detailed Engineering Design)] are listed in Tables (2) and (3), respectively. The proposed Consultants and Experts have a great deal of  experience and expertise in the entire range of consultancy services and activities required for this Project.

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4.2.1 Key Project Personnel

1. Technical Team Leader (TTL) : Dr. Magdi Mohamed Eltayeb Zumrawi (MD) 2. Eng. Highway Expert : Eng. Ramakant Dwivedi (VOYANTS) 3. Structural Expert (Bridges): Dr. Abdalla Khogali (MD) 4. Soil & Material Expert: Eng. Soubhik Sadhu (VOYANTS) 5. Contract/Claims Expert:

B. K. Banati (VOYANTS)

6. Hydrologist Expert: Eng. Elsidig Omer A/Gadir (MD) 7. Surveying Consultant: Eng. Mohamoud Abd Elrahim Abd Elgiom (MD)