FOUNDATION

FOUNDATIONA foundation is the lowest and supporting layer of a structure.

 Foundations are generally divided into two categories: shallow foundationDeep foundation

According to terzaghi , a foundation is shallow if its depth is equal to or less than its width. In case of deep foundation the depth is equal to or greater than its width

There are a variety of shallow foundation types used in the construction of foundations. Columns Combined or Cantilevered Mat FloatingWall (strip) Spread Footings Slab on grade Basement crawl space

SHALLOW FOUNDATION

DEEP FOUNDATION

DEEP FOUNDATION

Types of deep foundation

Deep strip,rectangular and square footing.Pile foundation.Pier foundation or drilled caissan foundation.Well foundation or caissan.

Deep foundation are those foundation in which the depth of the foundation is very large in comparison to its width.

Piles foundation Pier foundatuon

Cassion or well foundation

PILE FOUNDATION

TYPES OF PILES

classification based on functionclassification based on material and composition.

piles may be classified as follows :

CLASSIFICATION BASED ON FUNCTION :based on the function or the use piles may be classified:end bearing pile ( they are used transfer load through water or soft soil to suitable bearing stratum.)friction pilescompaction pilestension or uplift pilesanchor piles fender piles sheet piles

If the loads is transferred through soft soil or water to a suitable bearing stratum by means of end bearing piles it is known as end bearing piles and point piles

FRICTION PILES

END BEARING PILES

END BEARING PILES

FRICATION PILES

If the loads is transferred to a depth of the relatively weak soil by meansof friction along the length of the piles it is known as friction piles.

COMPACTION PILES Piles are also used for compacting loose granular deposite these piles are short and are as known as compaction piles

TENSION PILESSometimes piles are used to resist upward forces these piles are subjected to tension are known as tension piles

BATTER PILESist In case of large lateral loads or inclined forces,piles driven at an angle resist forces effectively these are called batter piles

CLASSIFICATION BASED ON MATERIAL S AND COMPOSITION

concrete piles pre – cast cast in situ

driven piles (uncased or cased )

bored piles (pressure piles,under- Reamed piles. timber piles

steel piles h pilepipe pilesheet pilecompositie pilesconcrete and timberconcrete and steel

Cased piles uncased piles

Pre-casst piles

PRE CAST CONCRETE PILESCAST IN PLACE PILESThese are made by making a hole in the ground and filing it with concrete CASED PILESUNCASED PILES CASED PILES In cased piles , a thin metal shell or casing is first driven in the ground which is then filled with concrete .

UNCASED PILESIn uncased piles , a metal casing is first driven in the ground ,which is gradually withdrawn as the concreting is done

UNDER-REAMED PILESThese piles are most commonly used where excessive shrinkage andd swelling of clays out the use of shallow spread footing. The usual size of under –reamed piles is 150-250mm dia and 3000-4000mm long. The dia of the under –reamed portion is 2 to3 times the dia of the shaft.

TYPES OF PILES MINIMUM PILE SPACING ( centre to centre distance)Friction piles - 3d where d is the diameter of circumscr - bing circle for non –circular section or 900mm which ever is more end –bearing piles passing though relatively compressible Strata - 2.5d or 750mm whichever is more End bearing piles passing through compressible strata and resting in stiff -3.5d or 1050mm which ever is moreClay end bearing piles on rock - 2d or 1.75x diagonal dim of pile of noncircular sect ion or 600mm whichever is moreCompaction piles - 2d or 600 mm whichever is more

TYPES OF PILE CHOSEN DEPENDS ON FOLLOWING FACTORS: What type of pile is readily available Location & type of structure (magnitude of loading) Ground Condition (soil type) Cost Durability

TYPES OF PILE CONSTRUCTION

Displacement Pile

- It cause the soil to be displaced radially as well as vertically as pile shaft is driven or jacked into the ground.

Non Displacement Piles

- It cause the soil to be removed and the resulting hole filled with concrete or a pre cast concrete pile is dropped into the hole and grouted in.

DISPLACEMENT PILE METHOD NON -DISPLACEMENT PILE METHOD

It’s a vertical bridge support. It’s a foundation for carrying a heavy structural load which is constructed in site in a deep excavation.

PIERS

CONSTRUCTING THE PIERS FRAMINGConstructing

POST FOOTING AND DETAILS

RAMP IS INSTALLED RAMP IS BOLTED

FLOOR DECKING INSTALLATION COMPLETE PIERS FRAMES

WELL CASSIONS

It’s a prefabricated hollow box or cylinder. It is sunk into the ground to some desired depth and then filled with concrete thus forming a foundation. Most often used in the construction of bridge piers & other structures that require foundation beneath rivers & other bodies of water.

Box Caissons Excavated Caissons Floating Caissons Open Caissons Pneumatic Caissons Sheeted Caissons

TYPES OF WELL FOUNDATION OR CASSION

Caisson As One Of The Elements In This Structure

Wood Pile Steel H-Pile Steel Pipe Pile Site cased pile Precast Concrete Pile Composite Piles (Wood & Steel)

PILES MATERIALS

WOOD PILING

SHEET –H- PILING

MONOTUBES PILES

STEEL PIPE PILES

Dropping Weight or Drop Hammers commonly used method of insertion of displacement piles Diesel Hammers Most suitable to drive pile in non cohesive granular soil Vibratory Hammers or vibratory method of pile driving very effective in driving piles through non cohesive granular soil Jacking Method Of Insertion

METHOD OF INSTALLATION

Rapid controlled explosions can be produced by the diesel hammer. The explosions raise a ram which is used to drive the pile into the ground.Although the ram is smaller than the weight used in the drop hammer the increased frequency of the blows can make up for this inefficiency. This type of hammer is most suitable for driving piles through non-cohesive granular soils where the majority of the resistance is from end bearing.

Diesel Hammer

Vibratory methods can prove to be very effective in driving piles through non cohesive granular soils. The vibration of the pile excites the soil grains adjacent to the pile making the soil almost free flowing thus significantly reducing friction along the pile shaft.However the large energy resulting from the vibrations can damage equipment, noise and vibration propagation can also result in the settlement of nearby buildings.

Vibratory Method of Pile Driving

Pile Driving Rig - raise and temporarily support the pile that being driven and to support the pile hammer.

A weight approximately half that of the pile is raised a suitable distance in a guide and released to strike the pile head.

When driving a hollow pile tube the weight usually acts on a plug at the bottom of the pile thus reducing any excess stresses along the length of the tube during insertion.

Dropping Weight / Drop Hammers

Jacked Piles are most commonly used in underpinning structures By excavating underneath a structure short lengths of pile can be inserted and jacked into the ground using the underside of the existing structure as a reaction.

Jacking Method Of Insertion

BIBLOGRAPHY

DR .B.C PUNMIABARRYINTERNET

S N SINHA

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