Cast in Situ Pile Method Statement

PREPARED BY CHECKED BY APPROVED BY CERTIFIED (PTT) REV. DATE NO. D1 18-Feb-08 D2 21-Jul-08

NA

PTT PUBLIC COMPANY LIMITED ONSHORE COMPRESSOR STATION 4 PROJECT

NA REVISED BY

APPROVED BY NA NA

DESCRIPTION ISSUED FOR INTERNAL REVIEW REVISION ISSUED FOR ITB

SPECIFICATION FOR CAST IN-SITU CONCRETE PILING WORK SPC-0804.02-40.01.02 REV.D2 TOTAL 18 PAGES

AREA CODE OF SITE LOCATION GENERAL AREA: 010 PTT PLC. CONTRACT NO.

.

PTT PLC. PROJECT NO. 0804.02

CAST IN-SITU CONCRETE BORED PILING WORK SPECIFICATION

PTT PUBLIC COMPANY LIMITED ENGINEERING STANDARD

SPC 0804.02–40.01.02 Page 2 of 18 REV:D2

CONTENTS SECTION 1.0

SCOPE ..................................................................................................

3

2.0

DEFINITIONS............................................................................................

3

3.0

CODES AND STANDARDS ..............................................................................

3

4.0

SITE CONDITIONS ......................................................................................

4

5.0

SOIL INFORMATION

6.0

MATERIAL ..............................................................................................

5

7.0

PILE DESIGN ............................................................................................

7

8.0

PILE PRODUCTION ......................................................................................

8

9.0

PILE PLACEMENT .......................................................................................

9

10.0

PILE LOAD TESTS – GENERAL .........................................................................14

11.0

PILE LOAD TEST PILE SET-UP ..........................................................................15

12.0

PILE LOAD TEST PROCEDURE

13.0

EVALUATION OF TEST RESULTS

14.0

BORE PILE TESTING

.................................................................................... 5

.........................................................................16 ......................................................................17

...................................................................................17

CAST IN-SITU CONCRETE BORED PILING WORK SPECIFICATION

PTT PUBLIC COMPANY LIMITED ENGINEERING STANDARD

SPC 0804.02–40.01.02 Page 3 of 18 REV:D2

1.0

SCOPE

1.1

This standard defines the mandatory requirements for the design, materials, installation and testing of cast in-situ concrete bored piles.

1.2

Each pile type shall be capable of sustaining the worst combination of working (service) loads of [1.0XDL + 1.0XLL + 1.0XWL] with due allowance for any possible negative skin friction.

1.3

The recommendation for the allowable pile capacities for both Cast in-situ Concrete Bored Piles and Precast Concrete Driven Piles are found in the Site Investigation Reports attached in the ITB.

1.4

Many piling works on this project shall be carried out adjacent to the existing EXISTING FACILITIES. Methods of pile placements proposed by CONTRACTOR shall be submitted to PTT/CONSULTANT for approval. a)

For structures within and close to the vicinity to the EXISTING FACILITIES, cast in-situ concrete bored piles are foreseen to minimize any vibration due to the Piling Work.

b)

For another areas and where vibrations from piling operations shall not impact the operation of EXISTING FACILITIES, precast concrete driven piles are envisaged.

1.5

CONTRACTOR shall supply all materials, mechanical plant, supervision and labour necessary for the pile placement as defined on the construction drawings and in accordance with the Specifications. All materials and workmanship shall comply with the specifications and related codes and standards referred to within this Standard.

1.6

Specification for Precast Concrete Piling Work shall be in accordance with SPC 0804.02-40.01.01

2.0

DEFINITIONS (Deleted)

3.0

CODES AND STANDARDS CONTRACTOR shall comply with all local and national laws, codes and regulations. Design, material and workmanship for piling shall be in accordance with the latest revision and amendments of the following standards and scopes of practice current at time of contract placement.

CAST IN-SITU CONCRETE BORED PILING WORK SPECIFICATION 3.1

3.2

PTT PUBLIC COMPANY LIMITED ENGINEERING STANDARD

SPC 0804.02–40.01.02 Page 4 of 18 REV:D2

The following codes and standards shall be used in conjunction with this standard: TIS 409-2525

Test method for compressive strength of concrete specimens

TIS 15

Portland Cement

TIS 566-2528

Concrete Aggregates

TIS 213-2520

Ready Mix Concrete

ASTM D1143-81

Standard test method for piles under static axial compressive load

ASTM D4945-2000

Standard test method for high-strain dynamic testing of piles

ASTM A82/A82M 2007

Standard specification for steel wire, plain concrete reinforcement.

TIS 24-2548 (2005)

Steel bars for reinforced concrete deformed bar

TIS 20-2543 (2000)

Steel bars for reinforced concrete round bar

ACI 543R (2000)

Design, Manufacture and Installation of Concrete Piles

ACI 308R

Guide to curing concrete

ACI 318-08

Building code requirements for structure concrete and commentary

TIS 194-2535

Ordinary low carbon steel wire

The following Engineering Standard shall be used in conjunction with this standard: SPC 0804.02-40.01

Specification for Civil Works

4.0

SITE CONDITIONS

4.1

The Piling Works are to be carried out project areas as state in scope of work.

4.2

The sites shall be stripped free of vegetation and levelled by CONTRACTOR and areas to be piled shall be excavated down to level planes with access from peripheral roads.

CAST IN-SITU CONCRETE BORED PILING WORK SPECIFICATION 4.3

PTT PUBLIC COMPANY LIMITED ENGINEERING STANDARD

SPC 0804.02–40.01.02 Page 5 of 18 REV:D2

All the existing reference elevations shown on the permanent benchmarks on the plant are referred to IEAT or Plant datum’s. Plant elevations for each area shall be established by CONTRACTOR in consultation with the PTT/CONSULTANT.

5.0

SOIL INFORMATION

5.1

(Deleted)

5.2

CONTRACTOR shall ensure that the Site Investigation Reports are sufficient for his needs to properly and effectively carry out the works. CONTRACTOR is responsible for undertaking any further investigations required at CONTRACTOR’s cost.

5.3

Pile design and length shall be based on the soil parameters recommendations contained in the Site Investigation Reports.

5.4

CONTRACTOR shall report immediately any circumstances, which indicate that the ground conditions differ from those expected from the interpretation of the Soil Reports. CONTRACTOR, shall however, be fully responsible for the effects of any such differing ground conditions.

6.0

MATERIAL

6.1

Cement

and

6.1.1 CONTRACTOR shall supply PTT/CONSULTANT with the Cement Manufacturer’s Test Certificates for each batch of cement used in the manufacturing process. 6.1.2 All cement shall be Type 1 Plus Cement to TIS15-2514/2517 and with a cement sulphate resistance. 6.2

Concrete

6.2.1 Concrete shall have minimum cube strength at 28 days of 45 N/mm2 (cylinder strength of 35 N/mm2). Slump shall not exceed 75mm. 6.2.2 The concrete shall contain a minimum cement content of 380 kg/m3 and aggregates shall not exceed 20mm maximum size. The free Water/Cement Ratio shall not exceed 0.40. 6.2.3 All cast in-situ concrete used shall be Ready Mixed Concrete, produced by a supplier in close proximity to the SITE and subject to the approval of PTT/CONSULTANT.

CAST IN-SITU CONCRETE BORED PILING WORK SPECIFICATION

PTT PUBLIC COMPANY LIMITED ENGINEERING STANDARD

SPC 0804.02–40.01.02 Page 6 of 18 REV:D2

6.2.4 CONTRACTOR shall submit to PTT/CONSULTANT full details of the concrete mix proposed together with the cement Manufacturers Test Certificate and these shall be subject to the review and comment of PTT/CONSULTANT before use. 6.3

Reinforcement

6.3.1 Deformed steel shall be grade SD40 in accordance with TIS 24-2548. Plain bar shall be SR24 in accordance with TIS 20-2543. Spiral wire shall in accordance with TIS 194-2535. 6.3.2 CONTRACTOR shall submit to PTT/CONSULTANT specific details and material certificates for the reinforcement he proposes to use. 6.3.3 CONTRACTOR shall store steel reinforcement in clean conditions. It shall be clean and free from loose rust and loose mill scale at the time of fixing in position and subsequent concreting work. 6.3.4 All binding wire shall be 2mm diameter black annealed mild steel wire. 6.3.5 CONTRACTOR shall supply to PTT/CONSULTANT copies of the Manufacturer’s Test Certificates for the actual reinforcement used in the manufacture of piles. 6.4

Quality Control

6.4.1 For each day’s production of piles, a minimum of nine cylinders (or cubes) shall be made and tested in compression in accordance with the requirements of TIS 409-2525. From each set of nine samples, three shall be compression tested at three days, three at seven days and the remainder compression tested at twenty-eight days. 6.4.2 All cylinders (or cubes) shall be marked and dated so that they can be identified with the appropriate pile. 6.4.3 The costs of providing the equipment, making the cylinders (or cubes) and all tests shall be borne by CONTRACTOR. 6.4.4 CONTRACTOR shall submit to PTT/CONSULTANT copies of the test result sheets which shall show the following information, cylinder (or cube) number, date and time of test, pile in which concrete was used for manufacture and the crushing strength. 6.4.5 Concrete shall be considered to be under strength if any of the works cylinders (or cubes) fail to meet the strengths specified as described above. Where tests show deviations from the required standards for crushing strength etc., PTT/CONSULTANT reserves the right to instruct CONTRACTOR to carry out remedial measures, or to prove that the pile concerned is acceptable. These measures shall include crushing additional cylinders (or cubes), boring replacement piles, the use of non-destructive tests or static load testing.

CAST IN-SITU CONCRETE BORED PILING WORK SPECIFICATION

PTT PUBLIC COMPANY LIMITED ENGINEERING STANDARD

SPC 0804.02–40.01.02 Page 7 of 18 REV:D2

CONTRACTOR shall bear all costs of all such tests and replacing unsatisfactory piles. 6.4.6 The use of water reducing plasticiser shall be subject to the approval of PTT/CONSULTANT. Calcium chloride admixture shall NOT be used. 6.4.7 The protective cover on the main reinforcement shall not be less than the following cast in-situ piles : With permanent steel casing Without permanent steel casing

-

50 mm 75 mm

6.4.8 CONTRACTOR shall inform PTT/CONSULTANT each day of the piling programme for the following day and give adequate notice of any intention to work outside normal hours and at weekends.

7.0

PILE DESIGN

7.1

General

7.1.1 The design of the pile length shall be based on the following parameters: ¾ Factor of Safety against Ultimate Compression Capacity ¾ Factor of Safety against Ultimate Tension Capacity ¾ Max. vertical displacement under Safe Working Vertical Load

= 2.5 = 3.0 = 10 m

7.1.2 CONTRACTOR shall prepare final design calculations for the piles for review by PTT/CONSULTANT. 7.1.3 CONTRACTOR shall ensure that the final design calculations for the piles are duly endorsed by a Registered Thai Engineer (Level II). 7.2

Lateral Load on Piles

7.2.1 The safe working lateral load on piles has been calculated for a maximum lateral pile head displacement (horizontal movement) of 8mm assuming a fixed connection between the pile and the pile cap. 7.2.2 The maximum working bending moment at the pile head is derived from the safe working lateral load at the top of the pile producing the following. The pile lever arm is to be determined by CONTRACTOR based on an analysis of the soil pile interaction using soil parameters from the Site Investigation Reports. 7.2.3 A check shall be carried out for shear reinforcement in the top of the pile for the ultimate lateral load.

CAST IN-SITU CONCRETE BORED PILING WORK SPECIFICATION

PTT PUBLIC COMPANY LIMITED ENGINEERING STANDARD

SPC 0804.02–40.01.02 Page 8 of 18 REV:D2

Cast in-situ concrete bored piles can be used to resist structural lateral loading by adding a steel cage in the pile to increase their flexural resistance. 7.3

Piles Subject to Compression and Lateral Load Piles shall be designed for the combination of ultimate compression load and ultimate bending moment.

7.4

Piles Subject to Tension and Lateral Load Piles shall be designed for the combination of ultimate tension load and ultimate bending moment.

7.5

All materials and workmanship shall comply with this Standard and related Codes and Standards referred to herein.

7.6

Allowable Pile Capacities CONTRACTOR shall determine the allowable capacities of the piles used, taking full account of the structural and geo-technical considerations, based on the soil data provided in the Site Investigation Reports. Length of piles shall be determined by CONTRACTOR and be subject to a pile test.

8.0

PILE PRODUCTION

8.1

All piles shall be reinforced over the completed total length. The main general longitudinal reinforcement for precast reinforced concrete piles shall be 1.5% minimum of the gross sectional area of the pile throughout the entire length. Reinforcement for piles shall be so arranged that axial pile tension forces can be properly and fully transferred to the pile cap.

8.2

Additional reinforcement shall be either 16mm or 20mm diameter high yield bars, required for the bending moment and axial tension in the pile head and shall be extended over a minimum length of 6m from the pile head.

8.3

The steel reinforcement shall be designed in such a way that the crack width of the concrete shall remain less than 0.2mm under all loading conditions. The reinforcement of piles subject to tensile loads shall be designed on the assumption that the tensile strength of the concrete is nil.

8.4

Piles that are subject to tension shall have sufficient longitudinal reinforcement to adequately transfer the tension forces from the pile cap into the pile shaft.

CAST IN-SITU CONCRETE BORED PILING WORK SPECIFICATION 8.5

PTT PUBLIC COMPANY LIMITED ENGINEERING STANDARD

SPC 0804.02–40.01.02 Page 9 of 18 REV:D2

Lateral reinforcement in the form of hoops and links of diameter not less than 6mm shall be used for a distance of three times the pile width from each end of the pile. The total volume of such reinforcement shall be not less than 0.6% of the gross total volume at 50mm maximum centres. The lateral reinforcement shall be not less than 0.2% of the gross volume of the pile spaced at not more than half of the overall width of the pile. The transition between the close spacing near the ends and maximum spacing shall be made gradually over a length equal to three times the width.

8.6

CONTRACTOR shall supply full details and calculations: a)

The type of pile offered and the proposed method of working.

b)

The standards of control intended to be used.

c)

The method by which the calculation and checking of the local bearing capacity and settlement of the piles shall be carried out.

d)

The tests proposed to be undertaken on the site.

e)

A complete description of the basis of acceptance of working piles with associated calculations to illustrate the validity of this basis.

9.0

PILE PLACEMENT

9.1

Boring CONTRACTOR shall take soil, rock or groundwater samples, or carry out soil tests in situ, while the pile is being bored. The samples shall be taken to an approved laboratory for testing. CONTRACTOR shall:

9.2

a)

Ensure that damage does not occur to completed piles.

b)

Submit a proposed sequence for boring to avoid damage to adjacent piles.

c)

Boring within 6m of new concrete work is unacceptable.

Establishment of Pile Lengths The end of the pile shall be founded with a minimum penetration of 1500mm in to hard material (SPT greater than 70/12).

CAST IN-SITU CONCRETE BORED PILING WORK SPECIFICATION 9.3

PTT PUBLIC COMPANY LIMITED ENGINEERING STANDARD

SPC 0804.02–40.01.02 Page 10 of 18 REV:D2

Near Recently Cast Piles CONTRACTOR shall not bore piles closer than 3 diameters to piles that have been cast within the previous 48 hours. CONTRACTOR shall monitor the head levels of all piles which have previously been cast during the installation of any new pile in the group to determine if heave occurs.

9.4

Temporary Casings CONTRACTOR shall use full length, temporary casings of a quality review and comment by PTT/CONSULTANT to maintain the stability of pile excavation which might otherwise collapse. During the installation of temporary casings in unstable strata, he shall maintain 500mm leading edge ahead of the excavation. Where this is considered to be impracticable, he shall adopt other precautions appropriate to the conditions such as mud mixing ahead of the casing, drilling under bentonite or providing a permanent liner. In such cases he shall submit detailed proposals to PTT/CONSULTANT. Prior to commencing excavation, CONTRACTOR shall ensure that temporary casings are: Free from significant distortion. Of uniform cross section throughout each continuous length. Free from internal projections and encrusted concrete during concreting, which might prevent the proper formation of piles.

9.5

Pumping From Boreholes CONTRACTOR shall not permit pumping from a borehole 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 does not have a detrimental effect on the surrounding soil or property.

9.6

Continuity of Construction Before commencing concreting operations, all required concrete shall be available on site. Concreting shall commence within hours of completion of excavation to ensure that the characteristics of soil at the toe of the pile are not impaired. CONTRACTOR shall ensure that the bottom of the pile shaft is clean and without any accumulation of debris or soft material immediately prior to concreting. If CONTRACTOR cannot demonstrate that the bottom of the pile shaft has been properly cleaned, a plug of dry concrete shall be placed in the bottom of the hole prior to installing reinforcement. This concrete shall be lightly tamped

CAST IN-SITU CONCRETE BORED PILING WORK SPECIFICATION

PTT PUBLIC COMPANY LIMITED ENGINEERING STANDARD

SPC 0804.02–40.01.02 Page 11 of 18 REV:D2

to provide a plug 1m tall. In the case of a dry hole, this concrete plug shall be placed within 30 minutes of completion of excavation. 9.7

Reinforcement Reinforcement cages shall be prefabricated, full length, before being installed in the excavation. CONTRACTOR shall make joints in reinforcement so that: a)

The full strength of the bar is effective across the joint.

b)

There is no relative displacement of the reinforcement during the construction of the pile.

Longitudinal steel shall be Grade SD40 bars for full depth of pile. Transverse (link) steel shall be continuous helix link of grade SR24 bars. 9.8

Concreting

9.8.1 Placing Generally The method of placing and the workability of the concrete shall be such that a continuous monolithic concrete shaft of the full cross-section if formed. CONTRACTOR shall: a)

Obtain PTT/CONSULTANT’s approval to the method of placing.

b)

Place the concrete without such interruption as would allow the previously placed batch to have hardened.

c)

Take all precautions in the design of the mix and placing of the concrete to avoid arching of the concrete in a casing. Allow no spoil, liquid or other foreign matter to contaminate the concrete.

d)

In the event of the groundwater level being higher than the required pile head casting level shown on the drawings, submit proposals for approval prior to placing concrete. Contractor shall not leave the pile head below the groundwater unless precautions are approved by PTT/CONSULTANT, are implemented.

9.8.2 Workability CONTRACTOR shall: Submit the slump factor proposed to PTT/CONSULTANT for review and comment before commencement of work.

CAST IN-SITU CONCRETE BORED PILING WORK SPECIFICATION

PTT PUBLIC COMPANY LIMITED ENGINEERING STANDARD

SPC 0804.02–40.01.02 Page 12 of 18 REV:D2

Ensure the concrete has sufficient workability to enable it to be placed by the method of placing approved and compacted when its final position and after all constructional procedures in forming the pile have been completed. 9.8.3 Compaction by Internal Vibrators Internal vibrators shall not be used unless: a)

The method of using PTT/CONSULTANT

has

been

review

and

comment

by

b)

It can be shown that no segregation or arching of the concrete will be caused.

9.8.4 Placing Concrete in Dry Borings When placing concrete in dry borings CONTRACTOR shall: a)

Place concrete by trunk or by pumping to ensure free drop is less than 2m.

b)

Take measures to avoid segregation and bleeding, and to ensure that the concrete at the bottom of the pile is not deficient in grout.

c)

Obtain approval of such measures from PTT/CONSULTANT.

9.8.5 Placing Concrete Under Water When placing concrete under water CONTRACTOR shall: a)

Ensure that there is no accumulation of silt or other material at the base of he boring.

b)

Place the concrete in such a manner that segregation does not occur using a tremie, CONTRACTOR shall not discharge concrete freely into the water. The use of bottom opening skips shall not be permitted.

c)

Take care during and after concreting to avoid damage to the concrete from pumping and de-watering operations.

d)

Ensure that the hopper and pipe of the tremie are clean and watertight throughout.

e)

Extend the pipe to the base of the boring and place in the pipe a sliding plug or barrier to prevent direct contact between the first charge of concrete in the pipe of the tremie and the water.

CAST IN-SITU CONCRETE BORED PILING WORK SPECIFICATION

9.9

PTT PUBLIC COMPANY LIMITED ENGINEERING STANDARD

SPC 0804.02–40.01.02 Page 13 of 18 REV:D2

f)

Ensure that, after it is opened to release concrete, the bottom of the tremie is always at least 2m below concrete surface.

g)

Maintain at all times a sufficient quantity of concrete within the pipe so that the pressure from it exceeds that from the water.

h)

Use a tremie with a pipe of internal diameter not less than 150mm for concrete made with 20mm aggregate. Ensure the design is such that external projections are minimised, allowing the tremie to pass through reinforcing cages without causing damage, and that the internal face of the pipe of the tremie is free from projections.

i)

Continue the placing of concrete by tremie up to a point of 0.2m above cut-off level to allow for removal of contaminated or otherwise defective concrete. Once the concreting operation has started, no interruption is permitted.

Extracting Casing

9.9.1 Workability CONTRACTOR shall extract temporary casings while the concrete within them remains sufficiently workable to ensure that the concrete is not lifted. 9.9.2 Concrete Level CONTRACTOR shall: a)

Once sufficient concrete is placed, ensure that the pressure head exceeds that of the groundwater, CONTRACTOR may raise the casing sufficient to remove one section. Thereafter, the casing shall not be removed until all concrete is placed.

b)

Place no concrete in the boring once the bottom of the casing has been lifted above the top of the concrete.

c)

Take adequate precautions in all cases where excess heads of water could occur as the casing is withdrawn because of the displacement of water or fluid by the concrete as it flows into its final position against the walls of the shaft.

CONTRACTOR shall obtain approval from PTT/CONSULTANT for the proposed method of working where two or more discontinuous lengths or casing (double casing) are used in the construction. 9.9.3 Vibrating extractors may be used subject to approval by PTT/CONSULTANT.

CAST IN-SITU CONCRETE BORED PILING WORK SPECIFICATION 9.10

PTT PUBLIC COMPANY LIMITED ENGINEERING STANDARD

SPC 0804.02–40.01.02 Page 14 of 18 REV:D2

Temporary Backfilling Above Pile Casting Level After each pile has been cast CONTRACTOR shall protect any empty bore remaining and carefully backfill as soon as possible with approved materials.

9.11

Setting Out CONTRACTOR shall carry out the setting out from the main grid lines of the proposed structure. He shall mark the pile position, immediately before installation of the pile with suitable identifiable pins or markers.

9.12

Pile Acceptance Criteria CONTRACTOR shall be totally responsible for the accurate setting out of each pile, which shall be centrally positioned at the location indicated on the drawings or as otherwise agreed by PTT/CONSULTANT. Position of piles shall be considered satisfactory, provided the following conditions are met: a)

Pile tops are within 75mm of the location specified by design drawings.

b)

Piles are within 2% of the specified slope.

c)

Eccentricity of the overall pile does not exceed 75mm in any direction.

d)

The piles, as finally placed, are not structurally damaged.

Repairs or changes due to improper placement of piles or due to structural damage shall be reported directly to PTT/CONSULTANT. This may include addition of new compensating piles.

10.0

PILE LOAD TESTS – GENERAL

10.1

One test shall be made for each rated pile type. The results of the test shall be subject to review by PTT/CONSULTANT to determine any possible changes in the penetration criteria for the construction piles or any changes in pile rating.

10.2

Test shall be conducted at the area near the locations where the new equipment will be constructed. This test location shall be selected by the PTT/CONSULTANT.

10.3

For those conducting the test, it shall be understood that the recommended penetrations for all piles, including the test pile, have been based on static analyses of the soils using the standard penetration blow counts as a rough measure of soil shearing strengths applicable to determining adhesion (skin friction) resistance along the pile surface and end bearing.

CAST IN-SITU CONCRETE BORED PILING WORK SPECIFICATION

PTT PUBLIC COMPANY LIMITED ENGINEERING STANDARD

11.0

PILE LOAD TEST PILE SET-UP

11.1

General

SPC 0804.02–40.01.02 Page 15 of 18 REV:D2

When preparing for, conducting and dismantling a pile test CONTRACTOR shall carry out the requirements of the various acts, orders, regulations, and other statutory instruments that are applicable to the work for the provision and maintenance of safe working conditions, and in addition shall make such other provision as may be necessary to safeguard against any hazards that are involved in the testing or preparations for testing. 11.2

Kentledge Where Kentledge is used, CONTRACTOR shall:

11.3

a)

Construct the foundations for the Kentledge and any cribwork, beams or other supporting structure in such a manner that there shall not be differential settlement, bending or deflection of an amount that constitutes a hazard to safety or impairs the efficiency of the operation.

b)

Ensure that the Kentledge is adequately bonded, tied or otherwise held together to prevent it falling apart, or becoming unstable because of the deflection of the supports.

c)

Ensure the weight of Kentledge is greater than the maximum test load and if the weight is estimated from the density and volume of the constituent materials allow an adequate factor of safety against error.

Testing Equipment In all cases, CONTRACTOR shall ensure that when the hydraulic jack and load measuring device are mounted on the pile head, the whole system will be stable up to the maximum applied load. CONTRACTOR shall provide means to enable dial gauges to be read from a position clear of the Kentledge stack or test frame in conditions where failure in any part of the system due to overloading, buckling, loss of hydraulic pressure and so on might constitute a hazard to personnel. The hydraulic jack, pump, hoses, pipes, coupling and other apparatus to be operated under hydraulic pressure shall be capable of withstanding a test pressure of 2 times the maximum working pressure without leaking. Display the maximum test load or test pressure expressed as a reading on the gauge in use and make all operators aware of this limit.

CAST IN-SITU CONCRETE BORED PILING WORK SPECIFICATION 11.4

PTT PUBLIC COMPANY LIMITED ENGINEERING STANDARD

SPC 0804.02–40.01.02 Page 16 of 18 REV:D2

Pile Head for Compression Test For a pile that is tested in compression, CONTRACTOR shall form the pile head or cap to give a plane surface which is normal to the axis of the pile, sufficiently large to accommodate the loading and settlement measuring equipment and adequately reinforced or protected to prevent damage from the concentrated application of load from the loading equipment. He shall ensure the pile cap is concentric with the test pile; the joint between the cap and the pile shall have a strength equivalent to that of the pile. Make sufficient clear space under any part of the cap projecting beyond the section of the pile so that, at the maximum expected settlement, load is not transmitted to the ground except through the pile.

12.0

PILE LOAD TEST PROCEDURE The procedure for downward load test for the pile shall conform to the following. a)

Load testing shall begin no sooner than 28 days after all piles of a set-up are completed.

b)

Loading shall be performed in increments of 25 percent of the rated pile capacity with a total load of 2.5 times the rated capacity or to soil failure, whichever occurs first.

c)

Loads shall be rebounded to zero following tests for 100, 150 and 200 percent of the rated capacity.

d)

Except for the final increment, all load increments shall be maintained until the rate of test pile settlement does not exceed 0.3 mm per hour or until four hours have elapsed, whichever is less. The final load increment shall be maintained for a minimum of 24 hours regardless of the settlement rate.

e)

Except for the final rebound, all rebounds shall be instantaneous. The final rebound shall be done in decrements of 25 percent of the rated pile capacity changed at not less than 30 minute intervals.

f)

Gauge readings shall be taken immediately before any loading to an accuracy of 0.03 mm. Settlement readings to the same accuracy shall be taken after implementation of each load increment at the following times : 1, 2, 5, 10, 15 and 30 minutes, 30 minute intervals thereafter and immediately before going to a higher load.

CAST IN-SITU CONCRETE BORED PILING WORK SPECIFICATION

13.0

PTT PUBLIC COMPANY LIMITED ENGINEERING STANDARD

SPC 0804.02–40.01.02 Page 17 of 18 REV:D2

g)

Rebound to zero load readings except for rebound of the final load, shall be taken immediately before and after load release and 15 minutes after load release. For the final load rebound, measurement of rebound shall be made immediately before and after release of the load and 24 hours after load release.

h)

Gauge readings shall be taken at reaction piles at the same time as those for the test pile.

EVALUATION OF TEST RESULTS The Rated Capacity shall not exceed the following: a)

A load that provides a safety factor of at least 2.0 with respect to soil failure, i.e. progressive pile movement under a sustained jack load or when gross incremental settlement exceeds 0.8mm/tonne.

b)

A load that produces a safety factor of at least 1.5 with respect to soil yielding represented by a point or the load/gross settlement curve tangent to the smallest radius of curvature.

c)

A load that does not result in gross settlement of more than 6 mm or plastic settlement of more than 2 mm. Plastic settlement is gross settlement minus the rebound from unloading.

14.0

BORE PILE TESTING

14.1

Pile Driving Analyser

14.1.1

Specific piles shall be tested using a Pile Driving Analyser (PDA) and the tests shall be carried out by an approved specialist employed by CONTRACTOR. Piles shall be PDA tested during bored piling. Re-drive PDA testing shall be carried out not less than 7 days after initial bore pile: only where initial PDA results show an ultimate capacity of less than 2.5 times working load capacity. All pilot piles shall be PDA tested; thereafter a percentage of production piling shall be subject to PDA testing.

14.1.2

The load capacity of pile shall be considered acceptable, if the PDA capacity for the re-drive tests show an ultimate capacity of at least two and half times the working load capacity.

14.1.3

A percentage of selected production piles shall be PDA tested 10% of first 100 piles and thereafter 1% of subsequent piles installed thereafter.

CAST IN-SITU CONCRETE BORED PILING WORK SPECIFICATION 14.2

PTT PUBLIC COMPANY LIMITED ENGINEERING STANDARD

SPC 0804.02–40.01.02 Page 18 of 18 REV:D2

Structural Integrity Testing

14.2.1

All test piles shall be selected from the production piles by PTT/CONSULTANT and tested by vibration method to determine the structural integrity of the pile shaft.

14.2.2

Integrity Testing (seismic profiling) shall be carried out on all piles.

14.2.3

The pile test and preparation of the test report and evaluation of test results shall be carried out by specialist consulting engineer employed by contractor.