YU-WEI HWANGYang, Cheng-HsuCheng-HsuYang2026-01-152026-01-152026-0302677261https://www.scopus.com/record/display.uri?eid=2-s2.0-105025027333&origin=resultslisthttps://scholars.lib.ntu.edu.tw/handle/123456789/735339In dense urban environments, buildings are often constructed in close proximity on potentially liquefiable soils, where complex seismic interactions can significantly affect their performance. This study investigated the structure–soil–structure interaction (SSSI) among three aligned, shallow-founded buildings on layered liquefiable ground using three-dimensional, fully coupled, nonlinear dynamic finite element analyses. The numerical sensitivity study explored the influence of building spacing, ground motion characteristics, and structural properties (e.g., short and tall buildings) on key engineering demand parameters such as settlement, tilt, and spectral acceleration. SSSI effects were most pronounced for edge buildings at small spacings and gradually became minor as spacing increased beyond two times the foundation width. Due to symmetric confinement, the middle building experienced less permanent tilt than the edge buildings. Under high-intensity pulse-like motions, all structures showed substantially larger settlements and significantly increased transient and permanent tilts as compared to that under non-pulse motions. Additionally, shorter buildings under SSSI were more sensitive to tilt amplification (as compared to isolated structures) at short spacing. Spectral acceleration demand at the foundation level increased with shaking intensity; however, it was reduced under pulse-like motions due to soil softening, which effectively isolated the foundation from free-field motion. In general, these behaviors, particularly the SSSI-induced foundation tilt patterns, were not observed in isolated or two adjacent structures. These findings highlight the importance of considering SSSI effects in performance-based design for improving urban resilience against seismic hazards.falseNumerical simulationPulse-like ground motionSoil liquefactionSoil-structure interactionStructure-soil-structure interaction[SDGs]SDG13journal article10.1016/j.soildyn.2025.1100412-s2.0-105025027333