Seismic response of bridges on pile foundations considering soil-structure interaction

This paper attempts to assess the influence of dynamic soil-structure interaction on the behaviour of bridges founded on rigidly capped floating vertical pile groups. A numerical model for the analysis of the soil-structure interaction of generic structures on pile foundations is presented based on a finite element approach for superstructure and pile group whereas the soil is assumed to be a Winkler-type medium. The method is applied to single piers representative for a class of bridges. Varying the soil condition and the foundation geometry, same comparisons are made with respect to the fixed base model. Special issues such as the contribution of the soil profile, of the local amplification and of the rocking at the foundation level are dis-cussed. Soil-structure interaction is found to be essential for effective design of bridges especially for squat piers and soft soil.