The last two decades have seen significant advances in understanding,
analysis and design approaches for pile groups and piled rafts. These advances
have been helped in no small measure by the accessibility and relatively low
computational cost of full three-dimensional finite element analysis of pile
group response, including increasingly sophisticated soil modelling. From a
practical viewpoint, however, much simpler approaches are used routinely in
design, at least for initial sizing and assessment of piled foundation
response. This paper builds on recent contributions that have presented simple
lumped models for the non-linear response of individual piles and pile groups,
and the associated raft-soil interaction. The focus is on two main aspects:
quantification of the role of non-linear response of individual piles in the
load distribution among piles in a group and the overall group response; and
the coupling of raft stiffness and pile group response in order to assess
differential settlements and load distribution among the piles. Extension of
existing software to incorporate non-linear pile response, and iterative
linking with raft foundation analysis, are presented. The paper includes
comparisons with rigorous numerical analysis and also with several case studies
from the field.