A comparison of different approaches for the modelling of shallow foundations in seismic soil-structure interaction problems

In this work, the performance of two different macroelement models for shallow foundations on sands is assessed by considering the dynamic response of a RC bridge subject to earthquake loading. The first macroelement model is formulated within the framework of kinematic hardening elastoplasticity with prescribed bounding surface (Grange et al. 2009). The second macroelement model has been recently developed within the framework of the theory of hypoplasticity (Salciarini and Tamagnini 2009). The results of a series of FE simulations show that a significant reduction of the computed structural loads can be obtained by taking properly into account the foundation-soil behavior, rather than assuming zero displacements and rotations at the pier bases. The two macroelements considered provide quite similar results, in spite of the large differences existing in their mathematical formulation