Investigating the seismic behavior of low-rise steel frames equipped with dual-core self-centering buckling-restrained brace

Buckling-restrained braces (BRBs) exhibit an exceptional capacity for seismic energy dissipation, offering substantial ductility in the face of applied loading. While BRBs offer excellent energy absorption and ductility, their inherent low post-yield stiffness leads to substantial residual drift and structural vulnerability after an earthquake. To address this limitation, this study proposes a novel dual-core self-centering buckling-restrained brace (DC-SC-BRB). The DC-SC-BRB leverages a bi-material design: low-yield-point steel for efficient energy dissipation and ultra-high-strength steel to enable self-centering post-earthquake. A simplified core-spring model was established to accurately simulate the DC-SC-BRB behavior. Subsequently, two and three-story DC-SC-BRB Frame (DC-SC-BRBF) models were compared with conventional BRBFs under various configurations using nonlinear static and time-history analyses. Results confirm the DC-SC-BRBF's effectiveness in significantly reducing residual inter-story drift ratios while maintaining adequate energy dissipation and ductility. Furthermore, the diagonal configuration of DC-SC-BRBs exhibited elevated self-centering capability amongst the investigated models.