Pile Foundation Classification 355le

PILE FOUNDATION AND ITS CLASSIFICATION Pile foundation is that type of deep foundation in which the loads are taken to a low level by means of vertical which may be of timber, concrete or steel. Now-a-days pile foundation is widely used to the columns of a multi-storied building. Pile foundation adopted when: 1. When foundation is loose and when hard stratum is available at a depth of around 10m to 15m. 2. The live and dead load coming from the structure is heavy 3. Construction of other foundations is non-economical. 4. Sub-soil water level is likely to rise or fall appreciably. 5. The structure is situated near sea shore or river bed and the foundation is likely to be affected by the scouring action of the water. Thus piles are useful for marine structures.

CLASSIFICATION BASED ON FUNCTION 1. End Bearing Pile 2. Friction pile 3. Combined End Bearing and Friction Pile

End Bearing Pile: s the load of the structure and transmits the load to the hard stratum. Thus these piles are adopted where hard stratum is available at a depth of 10 to 15m. Friction pile: In the case of friction pile, the load is carried mainly by the frictional resistance developed between the surface of the piles and the soil particles surrounding them. Thus these piles are used where deep bed of sand is available. Combined End Bearing and Friction Pile: When hard stratum is available below a sand medium of limited depth, this type of pile is used.

CLASSIFICATION BASED ON MATERIAL Based on material, piles are classified as follows: 1. Concrete piles Pre-cast concrete pile: - These piles are cast a convenient place and cured. After they attain sufficient strength they are driven into the ground. They are commonly of square cross section with chamfered edges. These piles can also be driven underwater. For driving the piles into the soil, blows are given by a hammer at the top using pile driving equipment.

Cast-in-situ concrete piles: - These concrete piles are cast in holes in the positions in which they are expected to occupy. 2. Steel piles In this type of pile, rolled steel sections or fabricated sections are used as pile the commonly used forms of steel are H-pile, Box-pile and Tube-pile.

The H-piles are usually of wide range flange section having the cross section in the shape of letter H. In box piles the steel plates are welded to form rectangular, square, octagonal sections and these fabricated sections are used as pile. In tube piles, circular tubes are used as piles. 3. Timber piles In this type of piles trunks of trees are used as pile. The wood should be free from any defects. These piles may be circular or square. The dimension varies from 30 cm to 50cm. At the bottom of the pile, an iron shoe is provided and at the top a steel plate is fixed. The pile can be driven to the ground by giving blows at the top. 4. Composite piles These piles are made by driving piles of two different materials driven one above the other. E.g. timber & concrete, steel & concrete. 5. Sand Piles These piles are formed by making holes in the ground and then filling holes with sand. A bore of required diameter usually 30cms formed either by driving a wooden pile or by auger or by forcing a pipe with closed end to the ground. The hole is then filled with sand. The top sand pile is filled with concrete to prevent the sand from coming upwards due to any lateral pressure.