Pile-soil-structure interaction effects on the dynamic performance of viaduct on pile group foundations

The role of Soil-Structure Interaction, in particular the soil-foundation-structure (SFS) interaction on dynamic behaviour of an elevated railway viaduct is investigated in this work. Initially the proposed fully 3-D FEM numerical non-linear method, adopting classic Drucker-Prager associative plastic failure criteria for soil and point contact elements to simulate pile-soil contact, is validated by comparison with experimental results. Then the numerical model is used to obtain the parameters of non linear springs able to fit the foundations behaviour. Finally an alternative and innovative procedure which allows the to modelling of the SSF interaction without excessive simplifications, consisting in transforming a spatial foundation system in an equivalent plain strain model, has been proposed. The full viaduct system, including group pile foundations and elevation, has been modelled with the different approaches and comparisons are made between the obtained results.