Analysis of Coupled Site and Soil–Structure Interaction Effects on the Seismic Response of Multistory Buildings According to EC-8 and ASCE7-16 Code Provisions

In strong seismicity areas, the structures experience seismic excitations that are affected by earthquake source effects and their propagating path, local site effects, and soil–structure interaction effects (SSIE). This study explores the impact of SSIE associated with site effects (SE) on the seismic response of multi-story buildings through a frequency domain solution within the EC-8 and ASCE7-16 code provisions. Low-to-mid-rise multistoried buildings are selected via their slenderness ratio to form systems associated with a wide range of soil profiles simulated using the random field theory. Shaking intensity ranging from moderate to strong is considered through an appropriate range of seismic magnitudes and shows that when the superstructure interacts with the nearby subsoil layers, the ground shaking level either amplifies or reduces the structural responses depending on the site category and the structure’s slenderness ratio. Results indicate that, in contrast to most common SSI investigations, seismic magnitude connected with the local geology affects the response of the structure and, in certain situations, makes SSIE unfavorable. The study's findings are presented in such a way that ratios can be utilized to show how SSIE differ from SE in terms of their impact on seismic base shear (BS) and roof displacement.