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Driven andBored PilesMADE BY :AHMED MOHAMED ZANATY 9103710AHMED ABDULLAH NEGM 9104441MOHAMED AHMED EL SAEID 9103644ABDELRAHMAN MOHAMED 9104286AHMED YOUSSEF 9100499DEPARTURE: COURSE:CONSTRUCTION & BUILDING FOUNDATIONUNDER SUPERVISION OF:PROF. ADEL BELAL1To view online:
What is Deep foundation ? A deep foundation is a type of foundation distinguished fromshallow foundations by the depth they are embedded into theground. There are many reasons a geotechnical engineer wouldrecommend a deep foundation over a shallow foundation, butsome of the common reasons are very large design loads, a poorsoil at shallow depth, or site constraints There are different terms used to describe different types of deepfoundations including the pile, the pier, drilled shafts, and caissons.2
What are Piles ? Piles are generally driven into the ground in situ; other deepfoundations are typically put in place using excavation and drilling.The naming conventions may vary between engineering disciplinesand firms. Deep foundations can be made out oftimber, steel, reinforced concrete and pre-stressed concrete.3
How piles are connected ? Foundations relying on driven piles often havegroups of piles connected by a pile cap (a largeconcrete block into which the heads of the pilesare embedded) to distribute loads which arelarger than one pile can bear. Pile caps and isolated piles are typicallyconnected with grade beams to tie thefoundation elements together; lighter structuralelements bear on the grade beams, while heavierelements bear directly on the pile cap.4
Pile installation Pile installation is as important as design. There are two methods ofinstallation :a)Installation by Drivingb)Installation by Boring5
Pile installation Before going through pile installation methods understand the following terminology.Driven pre-cast pile: The pile is casted in a yard brought to the site anddriven by some mechanism into the soil.Driven Cast-in-situ pile: A casing plugged at bottom is driven into the groundand then the pile is casted by removing or retaining the casing.Bored Pre-cast pile: A bore is made and the soil inside is removed and then a pilecasted in some yard is put into the bore.Bored Cast -in-situ pile: A bore is made the soil is removed and the pile is casted atsite in the bore.6
Driven Pile installation All pile driving equipment, including the pile driving hammer,hammer cushion, helmet, pile cushion, and other appurtenancesto be furnished by the Contractor shall be approved in advanceby the Engineer before any driving can take place. To obtain this approval, the Contractor shall submit a description ofpile driving equipment to the Engineer before pile driving begin.The description must contain sufficient detail so that the proposeddriving system can be evaluated by the Engineer.10
Hammer Types Drop hammer / Gravity hammer Single acting power driven hammer Double Acting Power Driven Hammer Diesel Power Driven Hammers Vibratory and Sonic Power DrivenHammers11
Drop hammer / Gravity hammer: This is the original piledriving hammer. It consists of a steel ram that is guidedwithin a set of leads. The hammer is raised to a certainheight and allowed to drop on top of the pile, thusproducing the driving reaction.Hammer Types12
Hammer Types Single acting power driven hammer: Hammers of this type arebasically power gravity hammers. The difference between agravity hammer and a single acting power hammer is that the ram(striking part) is encased in a steel frame work and is raised bysteam or compressed air rather than by the crane load lines. Thefrequency of the blows is also considerably higher than a drophammer. The ram mass is usually greater than a drop hammer andthe vertical travel is usually less than that of a drop hammer. Anytype of power hammer is usually more efficient than a drophammer because there is less time between blows for the soil to setup around the pile.13
Hammer Types Double Acting Power Driven Hammer: The ram is raisedby steam or compressed air, as in the case of the singleacting power hammer. When the ram approaches thetop of its stroke a valve is opened into a chamber atthe top of the cylinder allowing high pressure air orsteam into the cylinder forcing the ram downward.Some double acting hammers utilize a light ram,operating at a high frequency, to develop the energyblows comparable to those developed by heavier,slower acting hammers. The advantage of the lighterram hammer is that there is less time between blows forsoil to re-settle against the pile, thus increasing thedriving efficiency and decreasing the drive time.14
Hammer Types15 Diesel Power Driven Hammers: They are simply a onecylinder diesel engine consisting of a steel cylindercontaining a ram and an anvil. The ram is raised initially byan outside power source (crane) and dropped. As the ramdrops, it activates a fuel pump, which injects fuel into a cupin the top of the anvil. The ram continues down blocking theexhaust ports and compressing the air in the combustionchamber. A ball on the end of the ram, mating closely withthe cup in the anvil, forces the fuel into the hot compressedair between the ram and the anvil. The fuel then explodesforcing the ram up and forcing the anvil, and in turn, thepile down.
Hammer Types Vibratory and Sonic Power Driven Hammers: These are themost recent developments in pile hammer technology.They are comparatively heavy, requiring handlingequipment of greater capacity than required forconventional pile hammers. The Vibratory Hammer vibratesthe pile at frequencies and amplitudes which tend to breakthe bond between the pile surface and the adjacent soils,thus delivering more of the developed energy to the tip ofthe pile.16
Driven Pile installation1. Raising the piston (starting)2. Injection of diesel fuel andcompression3. Impact and atomization.4. Exhaust5. Scavenging17
Driven Pile installation1.Raising the piston (starting): For starting the diesel hammer, thepiston (ram) is raised by means of a mechanical tripping device and isautomatically released at a given height.2. Injection of diesel fuel and compression: As the piston falls throughthe cylinders, it activates a lever on the back of the fuel pump, whichinjects a measured amount of diesel fuel on to the top of the impactblock. Shortly after this, the exhaust ports are closed.18
Driven Pile installation3. Impact and atomization: Compressing all the air /fuel between theexhaust ports and the top Of the impact block, the piston continuesfalling until it strikes the top of the impact block. The heat generatedby the compression of air, in the presence of atomized fuel, causesthe explosion of the fuel, throwing the piston upward and forcing theimpact block downward against the pile.19
Driven Pile installation4. Exhaust: While moving upwards, the piston will pass and open theexhaust ports. Exhaust gases will escape and the pressure in thecylinder will equalize.5. Scavenging: The piston continues its upward momentum, whichdraws in fresh air for the nextcycle, cools the cylinders, and releasesthe pump lever. The pump lever returns to its startingposition, so thatthe pump will again be charged with fuel. Gravity stops the upwardmotion of thepiston and it starts falling through the cylinders onceagain.20
Pile installation Pile installation is as important as design. There are two methods ofinstallation :a)Installation by Drivingb)Installation by Boring27
Bored Piles Bored piles is another type of reinforced concrete piles which isused to support high building which has heavy vertical load. Boredpile is a cast-in-place concrete pile where the bored piles have tobe cast on construction site.28
Bored Piles29 Normally bored piling has be to carried on those tallbuildings or massive industrial complexes, which requirefoundations which can bear the load of thousands oftons, most probably in unstable or difficult soilconditions. Bored piling is cast by using bored pilingmachine which has specially designed drilling tools,buckets and grabs, it’s used to remove the soil androck. Normally it can be drilling into 50metres depth ofsoil.
Advantage & Disadvantage of BoredPiles30Advantage DisadvantageAbsence of vibration will not disturb adjacentpiles or structures.Susceptible to "wasting" or "necking" in"squeezing" ground.Extremely high capacity caissons can beobtained by expanding the base of the shaft upto three times the shaft diameter, thuseliminating construction of caps over multiplepile groups.Concrete is not placed under ideal conditionsand cannot be subsequently inspected.For many design situations bored pilesoffer higher capacities with potentially bettereconomics than driven piles.Water under artesian pressure may pipe up pileshaft washing out cement.
Bored Pile installation To install a pile you should drill a borehole of a specified diameterand depth. Next the borehole should be filled by fine-aggregatedconcrete and reinforced with a metal frame of a required cut. So,the bored piles are installed and concreted directly on a site. Thediameter varies up to 1500mm and depth - up to 10m or 30 m andmore. To increase bearing capacity the piles should be installedwith a widening at the bottom of the borehole (a foot of pile).Mostly such types of bored piles are used in situations when thereare heavy loads to a foundation and the few compressible soils aredeep-seated.32
Bored Pile installation The installation of bored piles is free of dynamic effects to soils andfoundations of existing buildings. This main advantage of boredpiles is more appreciable during a construction within the urbanzone. Moreover this type of foundations allows installing of a pile inany soil; even there are construction waste, remains from theprevious structures and boulder and cobble deposits.33
Bored Pile installation Quality control is very important during installation of bored piles. Allrigs are equipped with a special computer system to control a pileconcreting process. The monitoring piles’ parameters are depth,pressure of concrete mix, concrete volume and shape of piles.34
THANK YOU Made by :Ahmed Mohamed Zanaty 91037102. Ahmed Abdullah Negm 91044413. Mohamed Ahmed El Saeid 91036444. Abdelrahman Mohamed 91042865. Ahmed Youssef 9100499• Departure:Construction & Building• CourseFoundation• Under supervision of:Prof. Adel Belal39