METHODOLOGY / PROCEDURE FOR PILLING WORK

WORK METHODOLOGY / PROCEDURE FOR PILLING

 

MACHINERY EQUIPMENT AND MATERIAL

 a.    MACHINERY EQUIPMENT;

  

The following machinery and equipment shall be utilized for Bored cast in-situ friction pile;

Ø  Piling Rig

Ø  Rig Liner

Ø  Tremie’

Ø  Transit Mixture

Ø  Steel Cutting bending Machine and other machinery tool and tackles

 

b.    MATERIAL;

 

Ø  Reinforcement steel of Grade Fe 500 or Fe 500 D, RMC Concrete

Ø  Cover blocks

Ø  Binding wire and other necessary materials

WORK METHODOLOGY

 

 

a)    Before start the desired work following things to do ;

Ø  Selection of Rig, Inspection and Legal documents compliance need to check prior to start the work

Ø  Ensure safety clearance from adjacent activity.

Ø  Work permit system need to follow from client i.e safety permit

Ø  Need to barricade the work area

Ø  Deployment of signal man to guide vehicle moment during boring , concerting and excavation work

Ø  Covering bored piles in silent working hours.

Ø  Soil investigation report review and drawing specification status.

 

b)   Boring of pile shaft ;

Ø  Before boring of each bored pile, identify any possible obstruction and confirming founding level by site inspection.

Ø  Set out the correct position of the bored pile on site .by surveyor total station machine.

Ø  Boring operation shall be carried out after centering the hydraulic rotary rigs on desired point /Location.

Ø  To check whether the pilling rig is vertically centered on the desired point on the pile bore.

Ø  The temporary casing shall be driven up to a depth from where no collapse of the bore shall be occurring by rotary pilling hydraulic rig machine.

Ø  The centerline of guide casting shall be checked with respect to established reference point by surveyor before continue further boring point.

Ø  Bore the pile in soil using auguring method .the auger is lowered down by a telescopic boom to excavate soil and retrieve the auger to the top after excavation.

Ø  Move the auger with soil in it away from the excavated hole by swinging the machine .rotate the auger in the opposite direction to remove the soil from the auger.

Ø  The auguring progress is repeated until the required depth is reached or hard layer or rock is reached.

Ø  If necessary, use a bucket to clean the bored hole with the process similar to the auger. However, for dumping of soil/spoils, the bucket needs to be released by pulling a pin manually.

Ø  For hard soils and solid rocks, if necessary, rock auger head can be employed to grind into hard soil and rock and subsequent removal of fragments by bucket.

Ø  Extension of the steel casing can be done by welding on additional casing during excavation. The method may vary from site to site, depending on the soil condition .if the soil is soft simple full welding is sufficient.

Ø  Continue the above procedure until the tentative completed level / sound rock level has reached. Soil samples and rock fragments will be collected for inspection.

Ø  Bore log sheet will be maintained regularly.

 

c)    Cleaning of pile shaft ;

Ø  The pile shaft shell be cleaned by the bucket if there are suspected loose material at the toe. The presences of water in the shaft are ok, provided there are no collapses of soil in the hole.

Ø  This can be checked with when the withdrawal of bucket, there shall be no debris, soils or rock fragments in the bucket after cleaning.

Ø  The depth of the pile is checked using a weighted measuring tape/Chaining.

 

d)   Preparation of reinforcement bars;

Ø  Only tested and approved steel will be used for fabrication.

Ø  The reinforcement and link cage is prepared, prefabricated prior to the completion of the bore pile.

Ø  The link shall be prepared first and subsequently toe the required amount of reinforcement, spaced equally onto the link.

Ø  Place circular spacers onto the spiral link at intervals required by the design.

Ø  Only anticorrosive coated bar will be used. Touch up will be carried out in case of any damages of coating.

 

e)    Installation of reinforcement bars ;

Ø  When the reinforcement cages are ready, than can be installed into the pile.

Ø  Only inspected and approved cage will be used.

Ø  For lifting the cage mechanical bored pile machine is used.

Ø  The prefabricated cage shall be lowered down into the hole, segment by segment by lifting the entire cage with rotary machine .the top of the cage will be tied with suitable hook for lifting of the cage.

Ø  Shall lapping of reinforcement is needed; a lap length shall be as per the structural consultant requirement. The laps shall be done using welding or tied with binding wire.

Ø  Repeat the step above until required depth is reached.

 

f)     Concreting by Tremie method ;

Ø  The concreting operation shall be carried out in accordance with the description given subsequently using the crane or hydraulic rotary rig machine with, tremie method and signing of the checklist after inspection of the relevant items of measurement and quality.

Ø  The tremie pipe should be of dia of not less than 200mm

Ø  The concrete slump should be 150 to 180 mm just before use or as per project specification..

Ø  The hopper and tremie should be closed system embedded in the placed concrete through which water cannot pass. All joint shall be watertight.

Ø  The first charge of concrete should be placed with sliding plug.

Ø  The plug plate should not be pushed down in the bore.

Ø  The tremie pipe should always penetrate into the concrete with an adequate margin, minimum embedment shall be in the concrete.

Ø  Concreting will be carried out in one continuous operation to a stop – off level above the cut off level, agreed with the Client.

Ø  The entire tremie pipe can then be extracted piece by piece by piece as the concreting goes on.

Ø  After completion of concreting temporary casing will be removed with-in 10 to 15 mins.

Ø  Only approved grade and passed concrete will be used for casting.

 

 g)   Testing of Pile

Ø  Pile Integrity Test for all pile.

Ø  Dynamic Test

 

All tests will be conducted as per Project frequency.

 

 

Reference Documents

 

Document Number	Document Title
IS 456	Plain Reinforcement concrete code practice
IS 2502	Code practice for bending and fixing of bar for concrete reinforcement.
SP 34	Hand book on Concrete Reinforcement & Detailing.
IS 1786	Specification for High Strength Deformed Steel Bars & Wires for Concrete Reinforcement.
IS - 2911	Design & Construction of Pile Foundation.
	Pile Logbook