Non-linear analysis of piled raft foundations

A method of analysis is presented for piled raft foundations where the piles exhibit non linear load-deflection behaviour. The raft is analysed through the use of finite element methods, while the piles are treated as springs having a variable stiffness, so as to model any non-linear behaviour. The soil is treated as an elastic medium that may consist of layers of soil having different stiffnesses. Interaction between the piles in the group is assumed to remain constant even though the stiffness of the piles may change with load level. The method has been incorporated into the computer program GARP (General Analysis of Rafts with Piles). This program is used to analyse a tall building that was constructed on a piled raft foundation, and a comparison is made of the calculated and observed behaviour. Copyright ASCE 2007.