Piles are used to carry the load of the structure deep into the ground, and pile caps form the solid foundation on which the piers are then built.

A pile cap is a thick concrete mat that rests on concrete or timber piles that have been driven into soft or unstable ground to provide a suitable stable foundation.

Consider 150mm offset from the pile and space between piles as 2.5 times pile diameter. Effective depth, d = 1000-50-20/2 = 940 mm > 750mm; (2.5×600/2) Ok. The critical section of the pile shall be considered as 20% of the diameter of the pile inside of the face of the pile.