Soil–structure interaction of apartment complexes with extended underground parking

Buildings on flexible ground surfaces respond differently to earthquakes than those on fixed bases due to soil-structure interaction (SSI). Traditional SSI methods assume a rigid, massless foundation with limited dimensions, typically up to 80 m wide and 6.1 m deep. The question arises as to whether the conventional seismic design approach is applicable to buildings with extended underground parking which are common in Korean apartment complexes. In this study, we investigated the effects of the SSI on Korean apartment complexes with extended underground parking using a direct approach involving a three-dimensional non-linear response history analysis. The underground floor was modeled using shell elements to account for kinematic interaction, as well as both the inertial and back-stay effects. The results were compared with those of conventional SSI approaches outlined in ASCE/SEI 7–22. Our findings revealed that kinematic interaction remains valid beyond the limitations set by the ASCE/SEI 7–22. However, the inertial interaction of underground floor must be addressed when their size and embedment depth exceed the limitations imposed by ASCE/SEI 7–22. Finally, we tested the possibility of deducing seismic design loads for the design of Korean apartment complexes with extended underground parking following the “Korean Seismic Design Standard for Buildings.