Finite Element Analyses of Piled Foundations: Interaction Domains Under Undrained Conditions

Abstract

Most of the bridges in Europe countries are now approaching their design life. Therefore, at present crucial is the choice of the most suitable retrofitting solution taking the current design standards into account. From an economic point of view the costs related to the foundations adaptation are not negligible at all, even because design approaches are in general over-conservative. For instance, in case of piled foundations, the presence of the raft is conventionally disregarded in the calculation of the pile group bearing capacity under general loading. In this work a pile group foundation embedded in a silty-clay soil stratum is studied to emphasise how the use of a non-standard approach may allow to make more sustainable the interventions. An extensive 3D pseudo-static finite element numerical analyses campaign, under general loading, accounting for the non-linear soil mechanical behaviour, was performed. The results were interpreted in terms of interaction domains for the piled foundation system (raft + piles).