PILE WORK

3. PILE WORK

3. 1 Preamble 3.1.1 Scope of work
The work comprises supplying of labor, materials, plants, equipment, temporary huts and all other items necessary for the design and installation of the piles as shown on the drawings and described in these specification.
The work is to be executed in accordance with specification and contract documents and to the satisfaction of the Engineer. All tenders shall therefore furnish information about the type of piles they specialize in and other relevant details of design, execution, equipment, testing, etc, complete, in support of their capabilities.

The whole of the work and materials shall conform to the current edition of relevant British standards and codes of practice.

3. 1. 2 Responsibility for design and workmanship
The piling contractor will be responsible for designing and
installing the piles to satisfy the performance requirements and minimum design criteria laid down in these specification lie shall provide all necessary details and information to satisfy the Engineer who designed the foundations that his proposals will meet the specification. It will also be his responsibility to produce standard workmanships in the best possible manner, to effect the design in the actual conditions encountered on the ground or below . In particular he shall make whatever day to day minor modifications to the agreed proposals that may be found to be necessary to cater for minor variations in ground conditions. Any variations from the agreed principle shall be in accordance with the Engineer's approval.
3. 1. 3 Site conditions
The piling contractor will be deemed to have visited and inspected the site and surroundings before preparing his tender and to have made himself thoroughly acquainted with all details of the site, including those not specifically mentioned herein or on the drawings,

3. 1. 4 Existing services and Adjacent Buildings
The piling contractor will be responsible for any claims arising from damage to services or to adjacent structures or property, at the time of executing the work.

3. 1. 5 Pile length for purpose of payment
The length of each pile for purposes of payment shall be measured in accordance with the standard method of measurement for building and civil engineering work.

3. 1. 6 Records
The piling contractor shall keep on site a complete record of the changes in the nature of the strata through which each passes. Such records shall be made available for inspection by the Engineer during the progress of the piling contract and copy shall be supplied to the Engineer at the completion of piling work .
3. 2 Design
The pile is designed to carry as its part of the total support of the foundation loading. Specified in the drawings.

3. 2. 1 Responsibility
As stated in 3 .1.2, the piling contractor will be responsible for designing the piles and producing a piling that can carry safely the loads indicated on the foundation plans.
3. 2. 2 Approval of Design
Before accepting the piling contractor's tender, the Engineer will be required to satisfy himself that design proposals are sound and reasonable* To this end the piling contractor shall submit any calculations or supporting evidence which the Engineer may call for after receipt of tender .
3. 3 Concreting Materials and Workmanship
3. 3. 1 Materials
cement, aggregate and water to be used shall be in accordance with the requirement of section ( 4-2 ) "concrete work". The piling contractor shall submit details of reinforcements included in his design and tender. All reinforcements used in the piles shall be as per the approval of the Engineer and in accordance with section ( 4- 2) .
3. 3. 2 Concrete
The concrete mix shall be designed by the piling contractor to suit the piling system adopted and shall be dry as possible consistent with that system , and the method of compaction. However, the minimum cylinder strength at 28 days shall be 211 kg/cm2.
3.3.3 Placing and compacting
The concrete shall be placed in its final position as soon as possible and in any case not later than half an hour after mixing. Ready mix concrete must be placed immediately it leaves the mixing truck. The method of placing shall be such as to ensure that the concrete in its final position shall be dense and homogeneous. Concrete shall not be ordinarily placed under water. If water is present within the pile-shell a sealing group of approved quality shall be placed in the bottom of the shell for 1 to 1-2 m depth, the water shall then be pumped from the pile and concrete placed in the dry. Adequate precautions shall be taken to ensure that water leaking out of concrete shall not build up on top of it during the pouring of Concrete in pile shaft, and any such water shall be removed before more concrete is placed in the shaft, The pile shall be concreted in one continuous operation. If the continuity of placing the concrete is interrupted no further concrete shall be placed without the prior approval of the Engineer. The method of compaction shall be proposed by the contractor and approved by the Engineer before placing concrete .
3.3.4 Transporting concrete

Concrete shall be transported from the mixer to the position of the pile in such a manner that segregation of the mix shall not occur

3. 4 Piling Workmanship
3.4.1 Setting out
The main contractor will provide the piling contractor with all necessary layouts and take responsibility for their accuracy and check that the piling contractor executes the work in accordance with these layouts. The piling contractor shall set out the position of each pile.

3.4.2 Tolerances
The maximum permissible positional deviation of the center of each finished pile from the correct center point shown on the setting out drawing is 75 mm in any direction. The maximum permissible deviation from the specified inclination of any finished pile is 2-2.5 % .
The piling contractor shall bear the cost of any additional work which, in the opinion of the Engineer, may be necessary due to any pile being installed in apposition not within these tolerances.
3.4.3 Temporary lining
Adequate precaution shall be taken including the use of a temporary lining tube, water bearing or unstable strata, to prevent the ingress of water, to maintain any pile excavation to its full dimensions and to ensure that the pile shaft shall be formed to its full cross-sectional area, where there is a temporary lining it must be removed in the line of the pile in such a manner that no defect or damage will be sustained by the pile.
The depth to the average levels of the concrete surface of the pile shall be checked before and after any temporary linings are with draw. These measurements shall be recorded.

3.4.5 Drilling Mud
Drilling Mud may be allowed only with prior permission of the Engineer and subject to the piling contractor providing satisfactory evidence that its disposal will not foul or contaminate any part of the site or surrounding areas or services.
3.4.6 Cleaning the Excavation
Upon completion of any boring, the excavation shall be cleaned of all losses, disturbed and remolded soil to expose a dry base of undisturbed Material.
3.4.7 Inspection
After the tube has been installed in its final position, the Engineer will inspect the tube for proper plumb, location and other conditions. Only after his approval can the contractor proceed further in placing reinforcement and concreting the pile.
3.4.8 Jetting and pre-boring
Jetting and pre-boring may be used only with the prior permission of the Engineer.

3.4.9 Backfilling empty boring
Where trimmed level of any pile is more than 600nm below the starting level of the piles, empty boring shall be backfilled as soon as possible with sand of colour which contrasts with the surrounding natural soil .
3.4.10 Cleaning the site
The piling contractor shall remove from the site at intervals during the operation of the work, and on completion, all unnecessary plant, rubbish, water and debris resulting from his activities.
3.5 Pile Testing
Tests of completed piles shall conform to British standards CP 2004
3.5.1 Notice of commencement
The Engineer shall be given at least 40 hours notice before the commencement of each test .

3.5.2 Supervision of pile tests
The piling contractor shall Keep the tests under continuous and competent supervision to the satisfaction of the Engineer, All necessary facilities shall be provided to enable the Engineer to check reading during the progress of the tests.
3.5.3 Testing assembly
The piling contractor shall submit complete details of the testing assembly and all details of the proposed arrangement and procedure for test loading for approval of the Engineer before the installation of tension piles. The details shall include a complete list of all equipment being used in the test, including manufacturer's name and the reference number of the equipment.
3.5.4 Test report
At the conclusion of work each day the piling contractor shall send to the Engineer a copy of his daily record sheet . The piling contractor shall also send to the Engineer within one week of the completion of each test, two copies of all record graphs and results of laboratory and in-situ tests conducted on the installation and testing of all trial piles. This information shall include a load Settlement, diagram plotted to scales .
3.5.5 Failure of contract test piles
In the event of a contract the failing to satisfy the test requirements the piling contractor will be instructed to test additional piles.
The piling contractor shall bear the cost of all additional and consequential work as the Engineer may consider necessary due to the failure on one or more piles, to satisfy the requirements of the loading test .
3.5.6 Rejection of piles
The Engineer reserves the right to reject any pile which in his opinion is not structurally sound, or is not in a proper position and alignment. The contractor shall be bound to pull out same and re-drive a new pile in its place , or leave the defective piles install at the contractor's cost one or more additional pile as per the directions of the Engineer in writing.
3.6 Other Pile Types
3.6.1 Steel piles
The work covered by this clause consists of furnishing all materials, labor and equipment and performing all operations for driving and completing steel piles as indicated on the drawings, in addition to driving and testing the test piles, all in accordance with the specification and as directed by the Engineer.
3.6.2 Materials
Steel piles shall be of the type and weights shown on the drawings and shall be manufactured from steel conforming v to ASTM-A36. All piles shall be straight and true to section and any pile which in the opinion of the Engineer, is defective in any way, shall be rejected and shall be replaced by the contractor.

3.6.3 Driving steel piles
Steel piles shall be driven vertically or inclined to true position and secured against lateral movement by leads or other suitable means approved by the Engineer, All piles driven out of line, but of plumb, with incorrect inclination, or twisted, broken or bent, otherwise damaged in driving shall be withdrawal and replaced with other piles, properly driven to the true position and alignment required and to the satisfaction of the Engineer. All piles shall be cut off at the levels indicated on the drawings . A steam hammer shall be used to drive the piles unless other equipment is permitted by the Engineer. Piles may be driven by a hammer and water jets or by water jets alone. An ample supply of water at adequate pressure shall provided. Piles shall be driven by hammer alone for the last 1.5 m of penetration, piles shall be driven to depths or to penetration per blow as directed by the Engineer. Accurate records of the penetration per blow for the last 30 cm shall be kept for the guidance of the Engineer in determining allowable loads on the pile.
If proper resistance to driving is not attained at the predetermined length of pile, or when the length of piling required is in excess of the largest continuous length that can be supplied, an additional length of piling shall be added by butt welding. The joint details shall be as shown or as directed and fulfilling the requirements of AISC standards.
The contractor shall take all the necessary precautions to prevent any damage to the existing properties due to the piling work.