Pile and pile driving equipment

Pile and Pile Driving EquipmentsPrepared byDigvijay RamtekePrashant Devda

A pile is a long slender foundation member, made either of timber, structural steel or concrete which might be cast-in-situ or driven and acts as a structural member to transfer the load of the structure to a required depth in deep foundations carrying a load which may be vertical or lateral or lateral plus vertical.

What is pile

If the load is transmitted to the soil, the pile is called a FRICTION PILE.If the load is transmitted to the soil through the piles lower tip, the pile is called an END BEARING PILE.

Pile

Piles can be classified on the basis of either there use or material from which they are made.On the basis of use there are two major classification 1). Sheet Pile 2). Load PilePile Types

Retaining wallBulkheadCoffer Dam

Sheet piles are used primarily to create a rigid barrier for earth and water.Typical uses include cutoff walls under dams, and for coffer dams, bulkheads, and trenching.On the basis of the material from which they are made sheet piling can be classified as 1. Steel 2. Prestresses concrete3. Timber4. Composite

Pile Types

Steel H sectionTimber pile

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Composite pilePrecast concrete pile

Timber Treated with preservativeUntreated ConcretePrecast PrestressedCast in place with shellsAugured cast in placeSteelH section Steel pipeCompositeConcrete and steel Plastic with steel core Pile Types

The type size and weight of structure to be supported.The physical properties of soil stratum at the siteThe availability of materials for piles.The no. of piles required.The driving equipment.The durability required.Selection of piles

The operation of forcing a pile into the ground is known as Pile driving.

What is pile driving

DropSingle acting steam or compressed airDouble acting steam or compressed airDifferential acting steam or compressed airDieselHydraulic Impact and driversVibratory drivers

PILE HAMMERS

Drop hammer is a heavy metal weight that is lifted by a hoist line, then released and allowed to fall onto the top of pileBecause of high dynamic forces, a pile cap id positioned between the hammer and pile headStandard drop hammer weight:500-3000 lbSuitable for driving piles on remote projects that requires only a few piles and for which time of completion is not important factorA drop hammer can deliver 4-8 blows per minuteDrop Hammer

Drop Hammer

Drop Hammer

It has freely falling weight, called a ram, that is lifted by steam or compressed airWhen the piston reaches the top of stroke , the steam or air pressure is released and the ram falls freely to strike the top of the pileThese hammers rely solely on gravity acting on the striking weightThe heavy weight strikes with low velocity due to short fall distance (usually 3ft, limited to 4ft)Hammers are available in sizes varying from about 7,000-1,800,000 ft-lb of energy per blow40-60 blows per minute

2. Single acting steam or compressed air

Single acting steam or compressed air

Single acting steam or compressed air

The striking ram(piston) is driven by compressed air or steam both when rising and when falling.Double acting hammer commonly delivers 95-300 blows per minutesLower blow counts are for the larger hammer and higher counts for the smaller hammers In comparison with single acting hammer, the ram of double acting is only 10-20%, 90% of its energy is delivered by action of air or steam.Advantageous when driving light to medium weight piles into soils having normal frictional resistance

3. Double acting steam or compressed air

It is modified single-acting hammer.The air or steam pressure used to lift the ram is not exhausted at the end of upward stroke but it is used to accelerate the ram on the down strokeThe no. of blows per minute is comparable with that of Double acting hammer.Weight and equivalent free fall are comparable with Those of single acting hammerIt has advantage of single & double- acting hammer

4. Differential acting steam or compressed air.

5. Diesel hammer

It is a self contained driving unit that does not require an external source of energy such as air compressor or steam boiler.It is simpler and more easily moved from one location to another than steam hammerOpen end diesel hammer deliver 40-55 blows per minute and closed end models operate at 75-85 blows per minuteIt works well in cohesive or very dense soil layersThe hammer may not operate when driving piles into soft grounds.

Diesel hammer

Diesel hammer

They are reported to have an efficiency of 90% or better in delivering energy to pilesMore efficient than steam, air or diesel hammers.It operates on differential pressure of hydraulic fluid instead of compressed air or steam. hydraulic drop hammer:- ram is lifted by hydraulic pressure to preset height and allowed to free fallDouble acting hydraulic hammer:- ram is lifted by hydraulic pressure and is also driven hydraulically on its downward stroke

6. a)Hydraulic Impact hammers

Press in hydraulic pile drivers, which can be used for thrusting and extracting steel H piles and steel sheet piles.The pile driver grips the pile and then pushes the pile down approx. 3 ft. At the end of down stroke, the pile is released and the gripper slides up the pile 3 ft to begin the process of another push It develops 140 tons of pressing or extracting forceAre compact, make minimal noise and cause very little vibrationSuited for driving pile in areas where there is restricted overhead space

6. b)Hydraulic Drivers

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Effective when piles are driven into water saturated non cohesive soilsThe drivers may experience difficulty in driving piles into dry sand or similar materials or into non cohesive soils that do not respond to vibrations.The vibrations are transmitted to pile because it is rigidly connected to driverFrom pile the vibrations are transmitted to adjacent soil.The agitation of the soil materially reduces skin friction between the soil and pileIt is powered either electrically or hydraulically, therefore a generator or hydraulic power pack is needed

7. Vibratory drivers

All hose connections including air hammer hoses and steam lines, that lead to the hammer must be securely attached. Hydraulic hammer hoses can be under high pressure and heat, so you must always protect these lines. Hanging or swinging pile driver leads must have fixed ladders for access.Workers can not stay on the leads or ladders when piles are being driven.All workers must wear hearing protection during pile driving operation.Pile Driving safety