Seismic Structure-Soil-Structure Interaction between a pair of buildings with consideration of rotational ground motions effects

During an earthquake, buildings are analysed dynamically without any consideration of their neighbouring structures and usually this also neglects the influence of surficial rotational ground motion. Population growth and increased land costs have increased the spatial density of buildings in urban areas. This closer proximity of buildings to one another leads to more complex interactions between buildings and the surficial seismic ground motion field that includes both horizontal and rotational components. To address these issues, this paper explores the Structure-Soil-Structure Interaction (SSSI) between a pair of buildings, including the surficial horizontal and rotational ground motions. A reduced-order parametric model of this complex system is proposed. Ground accelerogram data recorded from the 6-DOF sensor SINAPS@ Kefalonia (Greece) post-seismic experiment and the SMART-1 array in Taiwan were employed. This extensive parametric study analyses over six million system/ground motion cases. Results suggest that the rotational ground motion can affect the seismic response when the SSSI is considered, producing an additional amplification of acceleration responses of certain structures. The impact of the rotational ground motion depends principally on the fundamental natural period of the building, and the SSSI depends mainly on the frequency ratio (here Ω_b) between the buildings.