A-312-I Bored Cast-In-Situ Piling.pdf HPCL MUMBAI

ENGINEERING SPECIFICATION FOR

BORED CAST-IN-SITU PILING WORK

FOR

HINDUSTAN PETROLEUM CORPORATION LTD. VISAKH REFINERY

DHT PROJECT

JOB NO. : 6261

DOCUMENT NO. : A-6261-A-312-I

TOTAL NO. OF PAGES: 08 (INCLUDING THIS PAGE)

0

03-02-2010 FOR BID ENQUIRY UAK ST PVO

REV.

DATE

DESCRIPTION

MADE BY

CHECKED

APPROVED

TOYO ENGINEERING INDIA LIMITED MUMBAI INDIA

CONTENTS

MUMBAI

INDIA

STANDARD ENG’G SPECIFICATION


T E S

A-312-I

TOYO ENGINEERING INDIA LTD.

ISSUED: 15-03-2006 CIVIL DESIGN DEPARTMENT PAGE 2 OF 22

PARA NO. DESCRIPTION PAGE NO. PART I - MATERIALS

1.0 GENERAL 5

1.1 Scope 5

2.0 APPLICABLE CODES 5

3.0 PRIORITY OF REQUIREMENTS 6

4.0 CEMENT 6

4.1 Material 6 4.2 Tests 6 4.3 Storage 6 4.4 Usage 6

5.0 COARSE AGGREGATE 7

5.1 Material 7 5.2 Storage 7 5.3 Usage 7 5.4 Sampling 7

6.0 FINE AGGREGATE (SAND) 7

6.1 Material 7 6.2 Storage 7 6.3 Usage 7 6.4 Sampling 8

7.0 WATER 8 7.1 Material 8 7.2 Storage 8 7.3 Testing 8

PARA NO. DESCRIPTION PAGE NO.

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8.0 STEEL REINFORCEMENT 8

8.1 Material 8 8.2 Storage 8 8.3 Inspection 8

9.0 COVER BLOCK 9

9.1 Material 9

10.0 CASINGS AND TREMIE PIPES 9

11.0 BENTONITE 9

11.1 Supply 9 11.2 Material 9

12.0 DRILLING MUD 9

PART II - WORKMANSHIP

1.0 GENERAL 10

1.1 Scope 10 1.2 Constructional Plant 10 1.3 Workmen and Staff 10

2.0 APPLICABLE CODES 10

3.0 PRIORITY OF REQUIREMENTS 11

4.0 EXCAVATION 11

4.1 General 11 4.2 Shoring 11

5.0 DESIGN MIX CONCRETE 11

5.1 General 11 5.2 Tests 11 5.3 Batching and mixing of concrete 12 5.4 Procedure for placing of concrete 12

PARA NO. DESCRIPTION PAGE NO.

6.0 REINFORCEMENT 12

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6.1 Bending 12 6.2 Lapping 13 6.3 Welding 13 6.4 Dowels 13 6.5 Spacing, Supporting and Cleaning 13 6.6 Bar Bending Schedules 13

7.0 BORED CAST-IN-SITU CONCRETE PILES 14

7.1 Standard 14 7.2 Constructional Plant 14 7.3 Boring 14 7.4 Concreting 15 7.5 Tolerances 17 7.6 Obstruction 17 7.7 Defective Piles 17 7.8 Pile Load Tests 18 7.9 As-Built Drawings 21

Annexure list for related Work Item Description (TWD) 22

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PART I - MATERIALS

1.0 GENERAL 1.1 Scope

This part of the specification covers the material specifications of Reinforced Cement Concrete to be used in the Pile Foundations. Any special requirements as shown or noted on the drawings shall govern over the provision of this specification.

2.0 APPLICABLE CODES

Note: - Wherever reference is made to IS Codes, on any page of this Technical Specification (including annexures), applicable year of publication of IS Code is as stated below. All work shall be carried out strictly in accordance with the Technical Specifications, unless otherwise approved by Engineer-In-Charge in writing. The Indian Standard Codes applicable to this section shall include but not limited to the following. IS 280-1978 : Mild steel wire for general engineering purposes.

IS 383-1970 : Coarse and fine aggregates from natural sources for concrete

(second revision), Reaffirmed 1990 IS 432-1982 : Mild steel and medium tensile steel bars and hard-drawn steel

wire for concrete reinforcement Part 1 Mild steel and medium tensile steel bars (Third revision) Reaffirmed 1995

IS 455-1989 : Portland slag cement. IS 456-2000 : Code of practice for plain and reinforced concrete (Fourth revision) IS 1786-1985 : High strength deformed steel bars and wires for concrete reinforcement (third revision) (superseding IS: 1139 - 1966) (Amendment 1), Reaffirmed 1990 IS 2386-1963 : Part II - Methods of test for aggregates for concrete: Estimation of deleterious materials and organic impurities (Amendment 1), Reaffirmed 1990 IS 2720-1985 : Part V - Methods of test for soils: Determination of liquid and plastic limit (second revision), Reaffirmed 1995 IS 2911-1979 : Part I/Sec.2 - Code of practice for design and construction for pile foundations Concrete Piles: Bored cast in situ concrete piles (First revision) (Amendments 3), Reaffirmed 1987 IS 8112-1989 : 43 Grade ordinary Portland cement. IS 12330-1988 : Sulphate Resisting Portland cement.

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3.0 PRIORITY OF REQUIREMENTS

In case of any variation and discrepancy in condition between the special conditions, this specification and codes, order of priority shall be as under:- (1) Special Conditions (2) This Specification (3) Codes

4.0 CEMENT 4.1 Material

Cement shall be 43 Grade Ordinary Portland Cement conforming to IS 8112, unless otherwise specified.

4.2 Tests

The Engineer-In-Charge will make necessary tests and analysis as he may consider necessary on each consignment of cement brought on the site for use in Works. Such tests will be based on the relevant Indian Standard Specifications. If such tests should lead to rejection of the consignment, cement from the rejected consignment shall not be used in the Works and the CONTRACTOR shall forthwith remove the entire consignment from the site. The costs of providing facilities of testing, taking delivery and subsequently removing such rejected cement shall be borne by the CONTRACTOR.

4.3 Storage

Cement shall be unloaded under cover in wet days and stored in dry, weathertight, properly ventilated structure with adequate provision for prevention of absorption of moisture from floor and sides, etc. Each batch of cement shall be stacked separately to permit easy access for inspection and a record shall be kept so that each consignment may be identified by a serial number, the quantities received, date of receipt, source of despatch, type of cement and daily cement consumption on site. Cement temporarily stacked near concrete mixers for a concrete pour shall be adequately protected with tarpauline and stacked on raised platform to the satisfaction of the Engineer-In-Charge. From the time that a consignment is delivered to the CONTRACTOR, tested and approved by the Engineer-In-Charge until such time as the cement is used in the Works, the CONTRACTOR shall be responsible for keeping the same in a sound and acceptable condition. Any cement which deteriorates while in the Contractor’s charge and is rejected as unsuitable by the OWNER/Engineer-In-Charge shall be removed from the site and replaced by an approved lot by the CONTRACTOR at his own cost.

4.4 Usage

Cement shall be used in the sequence in which it is received. Cement reclaimed from clearing bags or leaking containers shall not be used.

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No cement stored for more than three months shall be used in the Works without the written consent of the Engineer-In-Charge.

5.0 COARSE AGGREGATE 5.1 Material

Coarse aggregate for use in concrete shall conform to IS: 383. It shall be hard, strong, dense, durable, and free from impurities like dust, clay lumps, adherent coatings and having matter which can chemically act with the alkalies of cement and any other deleterious matter. These shall be obtained from approved sources. Unless otherwise mentioned, it shall be graded 20 mm nominal size.

5.2 Storage

Coarse aggregate of various sizes shall be stored at site, as separate stacks over clean and well maintained hard floor on areas not liable to flooding. Segregated aggregates shall be rejected.

5.3 Usage

Coarse aggregate which is not clean shall be washed with clear fresh water before use in the job.

5.4 Sampling

Sampling and testing shall be as per IS: 2386 under the supervision of Engineer-In-Charge and the cost shall be borne by CONTRACTOR.

6.0 FINE AGGREGATE (SAND) 6.1 Material

Fine aggregate shall conform to IS 383 (between grading zones I and II). It shall be well graded, coarse in texture, clean, hard, strong, free from salt, mica, clay, earth, organic matter, any soluble sulphate, gypsum, etc.

6.2 Storage

Fine aggregate shall be stored at site in adequate quantity on clean and well maintained hard floor on areas not liable to flooding to avoid mixing with foreign matter.

6.3 Usage

Fine aggregate shall be thoroughly washed at site with clean fresh water, such that the percentage of all deleterious matter is within the permissible limits as laid down in IS: 2386 (Part II). Use of sea sand is prohibited.

6.4 Sampling

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Sampling and testing shall be as per IS: 2386 under the supervision of Engineer-In-Charge and cost shall be borne by CONTRACTOR.

7.0 WATER

7.1 Material

Potable water shall conform to IS: 456. It shall be clean, fresh, free from oils, acids, alkalies, organic or other deleterious matter whether in solution or in suspension.

7.2 Storage

Water shall be so stored, that it remains free from all deleterious matter as mentioned above. The CONTRACTOR shall make adequate arrangement to store sufficient water at Works for all construction activities and for drinking purpose at no extra cost.

7.3 Testing

Engineer-In-Charge may require the CONTRACTOR to get the water tested from an approved laboratory at his own expenses. In case the water contains an excess of acid, alkali or any injurious salts etc. the Engineer-In-Charge may refuse to permit it’s use.

8.0 STEEL REINFORCEMENT 8.1 Material

All MS Round Bars shall conform to IS: 432 All HYSD Round Bars shall be of grade Fe 415 conforming to IS:1786. All binding wire shall conform to IS: 280 All reinforcing steel shall be free from defects such as cracks, pealing, rust, oil, paint, earth, all harmful defects and adhesions that may impair the bond and strength of the material. All binding wire shall be soft drawn mild steel wire of size not less than 18 gauge.

8.2 Storage

Reinforcement bars shall be kept in clean condition. All reinforcement shall be stored clear of the ground by use of timber or other bearers. Where reinforcement is stored in the open for long periods, it may be necessary to avoid excessive corrosion by protecting the reinforcement stack with tarpaulins.

8.3 Inspection

Every bar shall be inspected before assembling on the works and any defective, brittle, excessively rusted or burnt bars shall be removed. Cracked ends of bars shall be cut out.

9.0 COVER BLOCK

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9.1 Material

All cover blocks shall be of concrete (non sand-cement mortar) and of the same strength as that of the surrounding concrete and properly compacted. They shall be circular in shape and not square.

10.0 CASINGS AND TREMIE PIPES

The casings and tremie pipes shall be in mild steel and flexible pipe respectively. The temporary casing pipe shall have adequate wall thickness and strength to withstand driving stresses, stresses due to soil pressure, etc. without damage or distortion. All joints shall be water tight. The diameter of the casing shall be such, as to yield the specified nominal diameter of piles.

11.0 BENTONITE

11.1 Supply

The CONTRACTOR shall arrange for the supply of bentonite powder.

11.2 Material

The CONTRACTOR shall furnish to the Engineer-In-Charge with each consignment, a certificate from the manufacturer stating the properties of the bentonite powder. Properties of the bentonite powder used and quality control shall be as per IS 2911.

Bentonite powder shall be tested for its liquid limit which shall be more than 300 %. (Method of testing liquid limit shall be as per IS 2720 (Part V) - Items 3.4 and 3.5.1) Sand content in bentonite shall be approximately 7 % (i.e. 93 % passing through IS: 75 micron sieve, dry condition).

Use of temporary liner in lieu of bentonite to stabilize sides of boreholes shall not be permitted.

12.0 DRILLING MUD

The drilling mud shall conform to the requirement of Indian Standard Code of Practice for design and construction of Pile foundation IS 2911 (Part I).

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PART II - WORKMANSHIP

1.0 GENERAL 1.1 Scope

This part of the specification covers the construction, installation and testing of load bearing reinforced cement concrete bored cast-in-situ piles.

1.2 Constructional Plant

The CONTRACTOR shall be responsible for the supply, use, maintenance of all Constructional Plant, equipment so as to ensure smooth and efficient working of the job. The Engineer-In-Charge shall have access to the plant at all times.

1.3 Workmen and Staff

The CONTRACTOR shall ensure that he employs only capable and experienced labour force, foremen, other tradesmen, and supervisory staff on the job capable of handling the bored cast in-situ piling work in a workmanlike and efficient manner to the satisfaction of the Engineer-In-Charge.

2.0 APPLICABLE CODES

Note: - Wherever reference is made to IS Codes, on any page of this Technical Specification (including annexures), applicable year of publication of IS Code is as stated below. All work shall be carried out strictly in accordance with the Technical Specifications, unless otherwise approved by Engineer-In-Charge in writing. The Indian Standard Codes applicable to this section shall include but not limited to the following. IS 456-2000 : Code of practice for plain and reinforced concrete (Fourth revision) IS 516-1959 : Method of test for strength of concrete (Amendments 2) Reaffirmed 1991. IS 1199-1959 : Methods of sampling & analysis of concrete, Reaffirmed 1991. IS 2751-1979 : Code of Practice for welding of mild steel plain and deformed bars for reinforced concrete construction. IS 2911-1979 : Part I/Sec.2 - Code of practice for design and construction for pile foundations Concrete Piles: Bored cast in situ concrete piles (First revision) (Amendments 3), Reaffirmed 1987 IS 2911-1985 : Part IV - Code of practice for design and construction for pile foundations Load test on pile. (First revision) (Amendment 1), Reaffirmed 1995

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3.0 PRIORITY OF REQUIREMENTS

In case of any variation and discrepancy in condition between the special conditions, this specification and codes, order of priority shall be as under:- (1) Special Conditions (2) This Specification (3) Codes

4.0 EXCAVATION 4.1 General

Any excavation shall be started only after taking the existing ground levels jointly with the Engineer-In-Charge.

4.2 Shoring

The CONTRACTOR shall provide and maintain all planking and strutting as may be necessary to prevent any ground movement.

5.0 DESIGN MIX CONCRETE 5 .1 General

The CONTRACTOR is entirely responsible for the design of the concrete mix. The design is to be approved by the Engineer-In-Charge before commencing any concreting in the works. The CONTRACTOR shall make trial mixes using samples of coarse aggregates, sand, water and cement, which have been tested in an approved laboratory and to be used in the works.

5.2 Tests

Samples shall be drawn as per IS 1199 and cubes made as per IS 516. Testing for strength of concrete shall be as per IS 456. The drawing of samples should be spread over the entire period of concreting and also over the various mixing units. A minimum of six cubes shall be prepared from each sample, three for testing after 7 days and three for testing after 28 days. At least one sample shall be drawn per shift. The frequency of sampling and the acceptance criteria shall be as per IS: 456 It shall be Contractor’s sole responsibility to carry out preliminary tests of specimens at his own cost as per IS 456 and IS 516. He shall thereafter furnish to Engineer-In-Charge, a statement of proportions, proposed to be used for concrete mix. The use of suitable plasticizer shall be allowed to increase workability after approval of the same. The mix so designed shall be approved by the Engineer-In-Charge within the parameters of IS: 456.

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5.3 Batching and mixing of concrete

Proportions of aggregates and cement, as decided by preliminary tests, shall be by mass. These proportions shall be maintained during subsequent concrete batching only by means of weigh batchers capable of controlling the weights within one percent of the desired value. In case uniformity in materials used has been established over a period of time, only the quantities of fine and coarse aggregates may be converted into equivalent volumes for the purpose of volume batching if specifically permitted by Engineer-In-Charge. However cement shall be weighed. For moist aggregates, allowance shall be made for bulking in accordance with IS: 2386 (Part III). Sizes of boxes shall be such as to measure the correct quantity of aggregates to be used with one 50 kg bag of cement. While filling boxes, material should be thrown loosely into boxes and struck off without any compaction.

5.4 Procedure for placing of concrete

Before concrete is placed all arrangements, equipment and proposed procedure shall be approved by Engineer-In-Charge. The minimum slump should be 100 mm, when the concrete in piles is not compacted. The slump shall not exceed 180 mm in any case. Concrete shall normally be placed compacted in its final position within thirty minutes of leaving the mixer. The top of concrete in a pile shall be brought above the cut-off level to permit removal of all loose and weak concrete before capping and to ensure good concrete at cut-off level. The reinforcement cages shall be left with adequate protruding length above cut-off level for proper embedment in to pile cap. During chipping of the pile for casting pile cap, manual chipping may be permitted after three days of pile casting while pneumatic tool for chipping shall not be used before seven days after pile casting.

6.0 REINFORCEMENT: 6.1 Bending

The CONTRACTOR shall prepare bar bending schedules as per details given in IS 2502 and get them approved before proceeding with cutting and bending of bars. All bars shall be carefully and accurately bent by the CONTRACTOR in accordance with the drawings. The bars shall be placed in exact positions. The bars should not be bent or straightened in any manner that will injure the material. No reinforcement shall be bent when in position in the works, without approval whether or not it is partially embedded in hardened concrete.

6.2 Lapping

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As far as possible bars of the maximum length available shall be used. Laps shown on drawings or otherwise specified by the Engineer-In-Charge shall be based on the use by CONTRACTOR of bars of maximum length. In case the CONTRACTOR wishes to use shorter bars, laps shall be provided at no extra cost, after approval by Engineer-In-Charge.

6.3 Welding

Wherever specified all welding shall be carried in accordance with IS:2751. Only qualified welders shall be permitted to carry out such welding. Where welding is permitted, it shall be at the staggered locations. The welding procedure shall be approved by the Engineer-In-Charge and tests shall be made to prove the soundness of the welded connection.

6.4 Dowels

Dowels shall be left as shown in drawing or specified by Engineer-In-Charge. 6.5 Spacing, Supporting And Cleaning

All reinforcement shall be placed and maintained in the position shown on the drawings.

18 SWG annealed steel wire shall be used as binding wires. All bars crossing one another shall be bound with this wire, twisted to make the skeleton or network rigid so that the reinforcement is not displaced during placing of concrete. Bars must be cleaned, before concreting commences, of all scale, rust or partially set concrete which may be deposited there during placing of a previous lift of concrete. The bars shall be cleaned with dry gunny bags, if they are coated lightly with rust or other impurities. On no account shall the bars be oiled or painted nor shall mould oil be allowed to come in contact with the bars. Cement wash to bars shall not be permitted. During placing of concrete, the greatest care shall be taken to prevent any displacement or bending of the bar, ties, links, stirrups or fabric. A competent steel fixer shall be in attendance on the work to adjust and correct position of any reinforcement displaced.

6.6 Bar Bending Schedules

Bar bending schedules shall be prepared by the CONTRACTOR and shall be submitted to the Engineer-In-Charge in triplicate for approval well before bars are bent. The Engineer-In-Charge will check and return one copy for the Contractor’s use with modifications noted, if any. The cost of preparing the schedules will be deemed to be included in the rates for reinforcement in the Bill of Quantities. Any approval given by the Engineer-In-Charge shall, in no case, relieve the CONTRACTOR from being responsible for the accuracy and correctness of the bar bending schedules.

7.0 BORED CAST-IN-SITU CONCRETE PILES

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7.1 Standard

The requirements of IS: 2911 (Part I) shall generally apply. 7.2 Constructional Plant

The CONTRACTOR shall furnish for the Engineer-In-Charge's approval the details of all plant and equipment materials and temporary works required for the job which he intends using for installing the piles. Based on the site investigation data, CONTRACTOR shall also submit list of anticipated problems and remedial actions proposed by him to overcome these anticipated problems.

7.3 Boring 7.3.1 Due consideration shall be given to sub-soil conditions while selecting boring method.

Boring shall be done using direct mud circulation (DMC) technique for which bentonite slurry shall be used. The CONTRACTOR shall suitably design and install a plant for bentonite slurry mixing and recirculation.

7.3.2 Bentonite powder shall be mixed thoroughly with clean fresh water using a pump for

circulation. The percentage of bentonite used to make the suspension shall be such as to maintain stability of excavation in the bore. The density of the solution shall be 1.05 to 1.10 depending on the site conditions and the viscosity as tested by Marsh cone method shall be approximately 35-75 seconds. Control tests to check density, viscosity shall be carried out using suitable apparatus. Similarly test to check shear strength (range 1.4 to 10 N/m3) and pH value (range 9.5 to 12) shall also be carried out using suitable apparatus. These tests shall be carried out initially until consistent working pattern is established. Once this is done, the tests may be discontinued at the discretion of the Engineer-In-Charge.

7.3.3 The initial boring of about 1.50 m depth shall be done by using the bailer and the guide

casing/liner shall then be lowered in the bore hole. They are intended to ensure stability of the strata near ground level. The centre line of the liner shall be checked with respect to the reference points and verticality before continuing further boring, which shall be carried out with chisel upto the founding strata. For this purpose, a chisel of suitable diameter which shall not be less than the diameter of the pile minus 75 mm shall be connected to rods through which bentonite slurry shall be pumped by use of high pressure pumps. The chisel shall have suitable ports for the bentonite slurry to flow out at high pressure. The bentonite slurry and the cuttings through boring, which are carried to the surface by the rising flow of slurry shall pass through settling tank of adequate size to remove the spoils from the slurry before the slurry is recirculated to the boring.

7.3.4 The following precautions shall be taken by the CONTRACTOR during the boring

operations

(i) As bore is advanced in the ground, careful observation shall be made to decide, if the side walls are stabilized readily or, if they keep on falling in. In the event of side walls keeping on collapsing the CONTRACTOR shall increase the density of bentonite fluid to ensure that sides do not collapse. (ii) The level of bentonite suspension shall be such that the pressure exerted by the

same is always greater than the pressures exerted by the soils and external

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ground water. For this purpose, during construction, the level of bentonite suspension in the bore shall be maintained within the depth of guide liner at a level not less than 1 m above the level of external standing water, if any.

(iii) If hard rock is available, the pile shall be embedded by at least 500 mm into hard

rock and confirmed by Engineer-In-Charge. Rock samples shall be presented at site.

7.3.5 After the bore hole is drilled to its final depth, fresh bentonite slurry shall be pumped

through the chisel resting at the base of the bore, to remove completely all cuttings and other loose material from the base of the bore. Under additional high pressure, the bore base shall be thoroughly flushed after the chisel and the rods are removed for concreting.

7.3.6 Consistency of the bentonite slurry shall be controlled throughout the boring as well as

concreting operation in order to keep the bentonite stabilized as well as to avoid concrete getting mixed up with the thicker suspension of the bentonite slurry.

7.3.7 Pumping from a bore hole shall not be permitted unless a casing has been driven into a

minimum of 3 m of stratum which prevents flow of external ground water from other strata in significant quantities.

7.3.8 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 delay.

7.3.9 Prolonged delays in the commencement of concreting after the completion of the boring

shall not be permitted.

7.4 Concreting 7.4.1 Piles shall contain a minimum cement content of 400 kg per cu.m. 7.4.2 Concrete shall have a minimum slump of 100 mm. Special plasticizing admixtures, if

approved by the Engineer-In-Charge, can be added to concrete as per manufacturer's instructions at no extra cost to improve the slump without impairing the specified strength.

7.4.3 Concreting shall be done by tremie method as per IS 2911. After the bottom of pile bore

is thoroughly flushed, approved, with the reinforcement cage in position, tremie pipe of 200 mm dia shall be lowered in the bore. The bore shall be once again be flushed by bentonite slurry through the tremie to ensure that the bottom is cleaned again after placing the reinforcement. The tremie pipe shall be clean and watertight. FLUSHING OF PILE BORE BOTTOM IS MOST IMPORTANT PRIOR TO CONCRETING TO ENSURE THAT HEAVILY CONTAMINATED BENTONITE SUSPENSION IS NOT ACCUMULATED AT THE BASE OF BORING SINCE THIS IMPAIRS FREE FLOW OF CONCRETE FROM THE TREMIE PIPE. If the specific gravity of bentonite slurry exceeds 1.2, the placing of concrete shall not proceed.

7.4.4 Concrete in piles shall be placed continuously by a tremie pipe fed by a steel hopper at top. The lower end of the tremie pipe shall be equipped with a suitable plug or an

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approved automatic check valve as approved by the Engineer-In-Charge. The following specific precautions shall be taken during the concreting operations -

i) The tremie pipe shall extent right upto the bottom of the borehole at the

commencement of placing concrete and shall be raised slowly to establish a uniform flow of concrete.

ii) Sufficient embedment of the tremie pipe (2.0 to 2.5 m) in concrete shall be

maintained to allow for adequate margin against accidental withdrawal and to prevent re-entry of bentonite slurry in the pipe.

iii) The tremie pipe shall be held concentric in the bore throughout.

iv) The tremie pipe shall not be withdrawn until the completion of concreting work.

v) The concrete pour shall be carried out in a manner and in such time that concrete above the foot of the tremie remains workable until the casting of the pile is complete.

vi) Spot measurements shall be taken at suitable intervals to check that the tremie pipe has an adequate penetration into previous concrete.

vii) Concreting of the pile shall be in one single and continuous operation. Stage wise ramming shall be done with tremie. The entire concreting operation shall be completed in not more than two hours.

viii) The top of concrete in a pile shall be brought above the cut-off level, since the top concrete is loose and is weak because of contamination with drilling mud. This ensures good concrete at the cut-off level.

ix) Concrete shall be cast at least 1000 mm above the cut off level, for cut offs more than 1.0 M below ground level. For shallower cut offs, concrete shall be poured upto ground level to permit overflow of concrete for visual inspection, subject to a minimum of 300 mm above cut off level. No extra payment shall be made for concrete above cut off level.

x) It shall be ensured that volume of concrete poured is at least equal to volume of pile shaft being concreted.

xi) After each pile has been cast any empty bore shall be protected and carefully

backfilled as soon as possible with approved materials. Complete boring and concreting records shall be sent to the OWNER/Engineer-In-Charge for each pile. The records shall include the duration of concreting, tremie pipe lengths, and actual lengths of pile concreted and the volume of concrete placed. Typical data sheets of recording piling data shall be as given in Appendix - D of IS: 2911.

xii) Suitable precaution shall be taken to prevent segregation. 7.5 Tolerances

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The CONTRACTOR shall take special care and precautions to maintain positional accuracy and strict verticality of the piles while boring. The permissible tolerances are as under -

(a) Positional deviation - 75 mm/50 mm at cut-off level for group of pile/single pile

respectively. (b) Verticality deviation - 1.5%

If the, above tolerances are exceeded.

i) The piles are liable for rejection ii) The cost for making modification in the design of pile group or pile caps shall be

charged to the CONTRACTOR. iii) The cost involved in the actual rectification/modification shall be entirely charged

to the CONTRACTOR. iv) The CONTRACTOR shall maintain a record of actual pile locations, in the form of

a drawing and submit the information to the Engineer-In-Charge at suitable intervals.

v) The CONTRACTOR shall expose one group of piles during initial phase of

construction to demonstrate that the green concrete in one pile is not damaged while constructing adjoining pile at no extra cost.

vi) Any deviation from designed location, alignment or load capacity of any pile shall

be noted and adequate measures taken well before concreting of the pile cap and plinth beam.

7.6 Obstruction

If any obstruction to boring is encountered, the work shall cease and the CONTRACTOR shall notify the Engineer-In-Charge and submit for the latter's approval, his proposals for overcoming the difficulties. Not withstanding any such approval, the CONTRACTOR shall be entirely responsible for ensuring that the piles are bored to the required alignment, position and depth.

7.7 Defective Piles

Any defective pile due to any causes whatsoever shall be removed or ignored as directed by the Engineer-In-Charge, without affecting the performance of the adjacent piles or the cap as a whole. Any additional pile/piles required to be done in lieu of the defective (and hence rejected) pile shall be to the Contractor’s account only.

7.8 Pile load tests 7.8.1 General

Load tests shall in general be carried out as per IS: 2911 (Part IV) except as modified herein or directed otherwise by the Engineer-In-Charge.

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7.8.2 Number of Tests

Any number of test piles and working piles as specified in the Bill of Quantities or as decided by the Engineer-In-Charge shall be subjected to load tests. These shall be either designated on the drawings or specified/selected by the Engineer-In-Charge at site. However, for initial load tests, the number of tests in each mode, viz. Vertical compression, lateral load and pullout, shall be at least one for each type of pile. For routine load test, minimum number of tests in each mode shall correspond to 0.5% for each type of pile.

7.8.3 Maximum Test Loads And Assessment Of Safe Load

The maximum test loads & assessment of safe loads in piles for various load tests shall be as fallows:

Type Of Load Test

Test Load Condition

Maximum Test Load Assessment Of Safe Load

Vertical Compression

Load corresponding to i) Total settlement of 10% of pile

diameter. ii) Failure of pile. iii) 2 time the estimated capacity

whichever occurs earlier.

Least of the following values i) 2/3 of final load at which,

total settlement is 12 mm. ii) 1/2 of the final load at which

total settlement equals 10% of pile diameter.

Lateral Load corresponding to i) Total deflection of 12 mm. ii) 2 times the estimated capacity whichever occurs earlier.


total deflection is 12 mm. ii) Load corresponding to total deflection of 5 mm.

Initial Load Test

Pullout Load corresponding to i) 2 times the estimated capacity. ii) Until the load displacement

curve shows a clear break (downward trend) whichever occurs earlier.


total displacement is 12 mm.ii) 1/2 of the final load at which load displacement curve shows a clear break

(downward trend)

Routine Load Test

Vertical Compression

Load corresponding to i) Total deflection of 12 mm. ii) 1.5 times the estimated capacity whichever occurs earlier.


total settlement is 12 mm. ii) 1/2 of the final load at which total settlement equals 10% of pile diameter.

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Lateral Load corresponding to

i) Total deflection of 12 mm. ii) 1.5 times the estimated capacity whichever occurs earlier.


total deflection is 12 mm. ii) Load corresponding to total deflection of 5 mm.

Pullout Load corresponding to i) Total deflection of 12 mm. ii) 1.5 times the estimated capacity whichever occurs earlier.


total displacement is 12 mm.ii) 1/2 of the final load at which load displacement curve shows a clear break

(downward trend) 7.8.4 Testing procedure

The CONTRACTOR shall submit the description of his procedure for carrying out load tests for the approval of the Engineer-In-Charge. Approval of Engineer-In-Charge shall also be obtained after the test set up is complete, prior to commencement of loading. Any modifications required by the Engineer-In-Charge to this procedure shall be done by the CONTRACTOR without any additional cost.

7.8.5 Arrangements for Tests

(a) Pile to be tested shall have been cast at least 28 days before the loading.

(b) All arrangements for conducting the load test including kentledge, instruments for measuring loads, deflection etc., shall be arranged for by the CONTRACTOR at his own cost. The equipment provided shall be capable of slowly applying and maintaining the required test loads to within an accuracy of 1% and measure deflection to an accuracy of 0.01 mm. The equipment and the instruments comprising of hydraulic jacks, pressure gauge deflectometers etc. shall be tested regarding their accuracy from an approved laboratory and the test certificates shall be kept in the custody of the Engineer-In-Charge prior to taking up the test in hand at no extra cost.

(c) If anchor piles are used for providing the necessary reaction for tests, they shall be provided by the CONTRACTOR at his own cost. The CONTRACTOR shall furnish the details for the arrangements and shall be approved by Engineer-In-Charge.

(d) All load tests shall be made under the supervision of the Engineer-In-Charge.

(e) The pile head shall be at cut-off level of the pile and capped by an RC cap to provide a horizontal plane bearing surface upon which a steel plate shall be placed. Care would be taken to see that the pile cap has no soil support.

7.8.6 Routine Load Tests

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(a) The total test load shall be as specified in Cl. 7.8.3 and shall be applied in

increments of 20% of the estimated design load carrying capacity.

(b) Settlement readings shall be taken to an accuracy of 0.01 mm before and after the application of each load increment. Additional load shall not be applied until the rate of settlement under the previous increment is less than 0.2 mm per hour or 2 hours have elapsed, whichever occurs later.

(c) When loading has been completed, the full test load shall remain on the pile for 24 hours or for a longer period, if the necessity thereof is indicated by the rate of settlement of the pile.

(d) Unloading shall be carried out in the same steps as loading, allowing 30 minutes interval between stages. At each such load decrement, rebound shall be measured immediately before and after each decrement. When the load is fully released to zero, measurements of rebound shall be continued till the movement of the pile top is not more than 0.2 mm per hour.

7.8.7 Initial Cyclic Load tests

The procedure for carrying out the tests shall in general be similar to that indicated for Routine load tests in Para 7.8.6 above except as stated herein below -

(a) Alternate loading and unloading shall be carried out at 20% of the estimated

design load.

(b) Each stage of loading or unloading shall be maintained till the rate of movement of the pile top is not more than 0.2 mm per hour, provided that the minimum period is 2 hours for loading and one hour for unloading. In the end, full test load shall remain on the pile for minimum 24 hours.

7.8.8 Record of Load Test Results

The CONTRACTOR shall furnish a copy of all the recorded test data to the Engineer-In-Charge immediately on completion of each test. Later the CONTRACTOR shall furnish to the Engineer-In-Charge, 3 copies of a pile test report which shall include the following information wherever applicable -

(i) Identification of working pile/test pile (ii) Co-ordinate axes of pile, elevation of bottom of pile, cut-off level of pile. (iii) Tabulations of loads and settlement readings during loading and unloading of the

pile. (iv) Time-Load settlement curves along with computation for separating the friction and

bearing components for cyclic load tests. (v) Remarks concerning any unusual occurrences during the boring/installing or test

loading of the working piles/test piles.

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(vi) Description of soil conditions, ground water table, actual boring record and

concrete cube test results. (vii) All other observations relevant to the tests being conducted.

7.8.9 Defective Piles

Engineer-In-Charge reserves the right to reject any pile which in his opinion has not been constructed in accordance with the specification and approved construction drawing. The CONTRACTOR will not be paid for rejected piles. The increase in cost of the pile caps, beams and other measures adopted for strengthening as a result of rejection of defective piles shall be borne by the CONTRACTOR.

7.9 As Built Drawings

On completion of the work the CONTRACTOR shall submit a plan showing the exact location and length of each pile as constructed at site, as well as dates of concreting, cube test results etc. The original tracing of this drawing shall be submitted to the Engineer-In-Charge within specific period fixed by Engineer-In-Charge.

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ANNEXURE LIST

ENGINEERING SPECIFICATION AND WORK-ITEM DESCRIPTION RELATION

ENGINEERING SPECIFICATION WORK-ITEM DESCRIPTION REMARKS

TES NO. TITLE TWD NO. TITLE TP / X / NA A-312-I BORED ANNEXURE (1)

CAST IN SITU PI-01A MOBILIZATION FOR BORED (1) ( ) PILING CAST-IN-SITU PILING WORK WORK ANNEXURE (2)

PI-02A BORING FOR CAST-IN-SITU (1) ( ) CONCRETE PILES ANNEXURE (3)

PI-03 REINFORCEMENT (2) ( ) (DEFORMED) FOR CAST-IN-SITU PILES ANNEXURE (4)

PI-03A REINFORCED (2) ( ) CONCRETE FOR CAST-IN-SITU PILES (M25/M30/M35) ANNEXURE (5)

PI-04A INITIAL CYCLIC LOAD TEST (1) ( ) ANNEXURE (6)

PI-04B ROUTINE LOAD (1) ( ) TEST ON PILE ANNEXURE (7)

PI-05 PILE HEAD TREATMENT FOR (1) ( ) CAST-IN-SITU PILES NOTE : Related work Item Descriptions shall be read in conjunction with this

specifications as per above annexure list LEGEND

ATTACHED : NOT ATTACHED : X NOT APPLICABLE : NA TOTAL PAGES : TP

Documents

A-312-I Bored Cast-In-Situ Piling.pdf HPCL MUMBAI