On the Seismic Response of Irregular Concrete Building with Shark Dampers Considering SSI Effects

This study investigates the three-dimensional seismic response of plan-irregular reinforced concrete (RC) frame structures subjected to near-fault pulse-like ground motions. The primary scientific contribution lies in evaluating how perimeter-distributed, short-stroke displacement-activated hysteretic dampers interact with complex structural torsional modes under the coupled influence of soil–structure interaction (SSI). Through unscaled nonlinear time–history analyses, this research exposes a critical vulnerability: foundation flexibility elongates the structural period, moving the system into close resonance with near-fault pulse content and more than doubling peak inter-storey drift demands. Concurrently, we demonstrate that the supplemental hysteretic system provides immediate elastic stiffness that successfully counteracts this SSI-induced period elongation, restricting peak drift amplifications to under 0.21% while actively mitigating torsional twisting. These findings provide a quantitative framework for the dual management of foundation flexibility and torsional irregularity using short-stroke metallic yielding devices.