Seismic behavior of mid-rise reinforced concrete adjacent buildings considering soil-structure interaction

Abstract

This study aims to investigate the effects of structure-soil-structure interaction (SSSI), soil-structure interaction (SSI) and fixed-base (FB) assumptions on seismic behavior in mid-rise reinforced concrete (RC) buildings located on soft soil. Three–dimensional (3D) high ductility RC frames 5-, 8-, 10-, 13-, and 15-storey buildings are modeled as a fully nonlinear frame element. Five different structural cases were created: SSSI models with and without pounding, FB models with and without pounding, and SSI models. In the scope of this study, direct finite element modeling of 3D inelastic soil volume was considered. A detailed investigation has been carried out considering 65 different model combinations to reflect SSSI, SSI and FB modelling approaches. As a result, total of 1365 analyses using 21 different ground motion records, the lateral displacement demands and displacement profiles of the buildings were examined and presented. It is found that the seismic behavior of adjacent buildings located on soft soils is different from the fixed-base assumption. The buildings should not be evaluated alone, as neighboring buildings on soft soils affect each other. Neighboring building and soil effects should be considered for buildings up to 8-storey even no collision occurs. For buildings with higher than 8-storey, it may be reasonable to consider SSI only with neglecting neighboring building effects if there is no collision. If the seismic gap distance between adjacent buildings is insufficient and seismic pounding potential exists, neighboring building effects with soil-structure interaction should be taken into account independent from building height.