Analytical fragility curves of shallow-founded structures subjected to Soil-Structure Interaction (SSI) effects

Abstract

Soil structure interaction (SSI) may affect significantly the seismic vulnerability of structures with several mechanisms that depend on the mutual effects of soil properties and structural characteristics. A probabilistic-based approach is here applied to evaluate the effects of SSI on the fragility assessment of two selected benchmark buildings: a Reinforced Concrete with Infill Masonry Walls (RCIMW) and a Reinforced Concrete (RC). Analytical fragility curves were developed by performing non-linear 3D numerical simulations with Opensees that implements hysteretic materials and advanced plasticity models for representing non-linear soil conditions and structural configurations. The effects of soil deformability and structural flexibility on the non-linear response of the system (soil-foundation-structure) were assessed and discussed by referring to four limit states (slight, moderate, extensive and collapse) with respect to the maximum inter storey drifts.