Now the Friction Piles and Bearing Piles are extensively used for piers’ foundations

• Pile:A cylindrical or tapering usually vertical column (or set of columns) of timber, soil, concrete or steel, or sand or stone mixed in the soil. Pile is driven into the ground to provide a foundation for the vertical load or to improve the load bearing capacity of the ground, or to resist the horizontal load exerted by the earth or water pressure (latest is known as Sheet Pile)

Three major types of Piles:

(i) Friction Pile: A pile that is simply inserted into the ground and solely supported by the lateral friction developed between the surfaces of the pile and the ground

(ii) Bearing Pile or End-Bearing Pile: A pile which is inserted into the ground and is supported at its lowest end on some supporting surface usually horizontal surface

iii) Socketed Pile: A pile inserted into the ground having its lowest end held fixed into a socket-like hole. Such arrangement provides the dual support to that pile and hence to the load exerting body too; one is the support from below i.e. normal reaction and second is against any slippage

Information needed for a bridge to be supported on the rocks:

• Type, nature and formation of rock present under the piers – distribution and uniformity of a rock are checked

• Geological Structural Features of the rock under the piers and strike and dip of the bedrock

• Depth and nature of overburden over the bedrock and overburden under the piers

• Nature and distribution of the rocks and soils at the abutments