Analysis of Laterally Loaded Piled Raft Foundation

Abstract

A BEM (Boundary Element Method) based method has been developed for the analysis of laterally loaded piled raft foundation. This method considers the raft-soil contact contribution and all the interactions between the piles, the soil and the raft. The nonlinear soil response is accounted by a hyperbolic modulus reduction curve, while the nonlinear response of reinforced concrete piles is modelled accounting also for the influence of tension stiffening. The behaviour of laterally loaded pile foundation is strongly affected by shallower soil layers, which in turn are frequently influenced by suction. The latter aspect has been considered by implementing the Modified Kovacs model in the proposed BEM method. Moreover, the shadowing effect has been modelled using an approach similar to that described in the Strain Wedge Model. The proposed method saves computational effort compared to more sophisticated FEM (Finite Element Method) or FDM (Finite Difference Method) codes and provides reliable results. The validation of the method in the linear elastic range has been carried out by comparing parametric analysis results with those obtained by using the code APRAF, and a comparison with centrifuge test data is shown to verify its reliability.