Question

List the main load transfer mechanisms in pile foundation and comment about the optimal spacing of piles in a pile group.

Answer 1

The main load transfer mechanisms in pile foundation are-:

1. Friction Piles - Piles develop most of the pile-bearing capacity by shear stresses along the sides of the pile.

2. End Bearing piles -  End-bearing piles develop most of their load-bearing capacity at the toe of the pile, bearing on a hard layer of rock or very dense soil and gravel.

As per the IS code the minimum spacing for the end bearing pile should be 2.5d and the maximum spacing should be 3.5d.