3D Macro Element for Soil Structure Interaction

This paper presents a 3D non linear interface element able to compute Soil Structure Interaction (SSI). Several approaches exist to take this phenomenon into account: the following work is based on the "macro element" concept and is inspired on the work of (Crémer, 2001). The particularity of the macro element lies in the fact that the movement of the foundation is entirely described by a system of generalised variables (forces and displacements) defined in the foundation centre. The non linear behaviour of the soil is reproduced using the classical theory of plasticity. The failure surface is defined using an adequate overturning mechanism according to the work of (Pecker, 1997). The element is able to simulate the 3D behaviour of a circular rigid shallow foundation under cyclic and dynamic loading considering rocking. It is implemented into FedeasLab, a finite element Matlab toolbox. Comparisons with experimental results under monotonic static (Gottardi et al., 1999), cyclic (TRISEE, 1998), and dynamic conditions (Combescure et al., 2000, CAFEEL-ECOEST/ICONS, 2001) show the good performance of the approach