Analysis of a group of piles depends on the structure stiffness. The basic assumption is that for a stiff structure all piles experience the same settlement, while for a compliant structure each pile deforms independently - no interaction is assumed.
The maximum bearing capacity of a rigid pile foundation is given by:
number of piles in the pile foundation
single pile bearing capacity in the pile foundation
If adopting the NEN6743 standard then a coefficient of capacity reduction ξ is introduced into the analysis depending on the number piles M and the number of CPTs (article 18.104.22.168). The maximum bearing capacity of a compliant pile foundation is determined according to the bearing capacity of the most stressed pile in the group as:
bearing capacity of the pile in the group