Regional seismic damage analysis considering soil–structure cluster interaction using lumped parameter models: a case study of Sichuan University Wangjiang Campus buildings

Regional seismic damage analysis of building clusters based on time history analysis enables damage evolution and distribution to be obtained for structural performance evaluation, seismic loss estimation, and post-earthquake emergency response decision support. Soil–structure cluster interaction (SSCI) effects have been shown to affect significantly seismic damage to buildings due to the influence of neighboring buildings through underlying soils. However, SSCI effects in current regional seismic damage simulations are either ignored or obtained with exceptionally high computation cost due to the common discretization of large scale soil domains using finite elements. To this end, lumped parameter models (LPMs) are presented in this work as a simple effective tool for regional seismic damage simulation of SSCI systems, which is particularly useful for parametric analysis and also enables fast regional damage assessments. The LPMs combine story-based multiple-degree-of-freedom buildings with ‘foundation springs’ that are used to represent soil–foundation interaction and foundation–soil–foundation interaction. Seismic damage analysis of 320 buildings on Wangjiang campus of Sichuan University in China is used as a case study. The results of the specific case study show, that in most cases, SSCI effects result in lower damage to buildings, especially on soft soils. However, the SSCI effects may lead to higher structural damage to buildings in some cases, e.g. those on stiff soils. The results also show that using nominal inter-story drift ratio which includes foundation rocking rotation as the damage index may underestimate story seismic damage to lower stories of tall buildings.