- To distribute a single load equally over the pile group and thus over a greater area of bearing potential,
- To laterally stabilise individual piles thus increasing overall stability of the group. And
- To provide the necessary combined resistance to stresses set up by the superstructure and/or ground movement.
Pile Cap Arrangement
- Spacing of the piles in the pile group
The following should be considered when determining the spacing of the piles:
- Overall cost of the foundation
- Nature of the ground
- Pile behaviour in the group
- Resulting possible heave or compaction of ground causing damage to adjacent structures
- Cost of pile cap
- Size and effective length of ground beam
- Type and size of pile
Piles should be placed in a suitable arrangement so that the spacing between piles ranges from (2-3) D (pile diameter) in case of isolated pile caps and (2-6) D in case of rafts supported on piles.
- The C.G. of piles should be placed as far as possible in the C.G. of loadstransmitted from the structure to the group of piles.
- In the case of presence of neighbors, piles should be away from the property line by a distance not less than D or as the pile installation method requires.
- The projection of the pile cap should be 10-15 cm.