Numerical Evaluation of Soil–Structure Interaction Effects on the Seismic Performance and Vulnerability of Reinforced Concrete Buildings

Abstract This study aimed to investigate whether the seismic performance and vulnerability of reinforced concrete (RC) structures were affected by soil–structure interaction (SSI). A set of RC frames located on three soil types were designed and modeled using the OpenSees finite-element framework. A nonlinear Winkler-based method was applied to model the soil–foundation interaction. Nonlinear static analysis and incremental dynamic analysis were performed to assess seismic behavior and fragility of RC buildings regarding the rigid and flexible-base assumptions. Numerical outcomes demonstrated the remarkable SSI role in modifying the fragility and performance of rigid base structures. Finally, a simple methodology is provided to directly obtain the vulnerability value for flexible-base structures by modifying the fundamental mode spectral acceleration.