Influence of Nonlinearity of Soil-Pile Interface on the Seismic Interaction of Nonlinear Soil-Piles-Bridge System

Post-seismic observations of recent devastating earthquakes have shown that the nonlinear behavior of the soil plays an essential and definitive role in development the damage to the system of soil-pilesstructure during the earthquake. Similarly, slips or collapse the soil-piles interface may cause harmful ruptures. Consequently, an analysis of these problems is necessary to take into account the non-linearity of the soil and the possibility of a slip or collapse at the interface of soil-pile under intensive seismic loading. This study aims to investigate these interaction aspects for soil-piles-structure under real earthquake record using a global approach with a three-dimensional finite difference code – FLAC 3D (Fast Lagrangian analysis of continua in 3 dimensions). The results confirm that the non-linearity of soil and soil-pile interface has a great influence on the response of piles and structure. They show that the consideration of the plasticity of the soil leads to attenuation of efforts, especially for soft loose soils. The simulation carried out in this study illustrate that the use of weak soil-pile interface leads to an increase of bending moment accompanied by a reduction of shear and normal forces in the piles. While, for a medium or high resistance interface, the efforts induced in the piles approaching of those induced in the case of perfect contact.