Effect of soil-structure interaction on seismic behavior of self-centering rocking piers supported on shallow foundations

The soil structure interaction (SSI) can severely affect the behavior of a structural system. This paper examines the impact of the SSI on the seismic performance of self-centering (SC) rocking piers. Finite element (FE) models of conventional reinforced concrete (RC) piers and SC rocking piers with and without energy dissipators are built and validated. The soil-foundation-structure interaction is modeled using the beam-on-nonlinear-Winkler- foundation (BNWF) approach, capturing the nonlinear behavior of soil. This approach is also validated, comparing the settlement and moment-rotation behavior of the numerical simulation and experimental results. Various scenarios, including different foundations and soil types, are considered. Nonlinear cyclic and dynamic analyses are performed. Three sets of fragility curves are obtained, assuming maximum drift, residual drift, and foundation settlement as engineering demand parameters (EDPs). The effect of earthquake frequency content and duration are also investigated. The results show that SC rocking piers can reduce settlements, but a relatively strong foundation is needed to carry out the expected seismic performance level and effectively reduce residual drifts.