Enhancing seismic resilience in steel frames with synchronized double-stage yield buckling-restrained braces
Hesam Azizi, Jamal Ahmadi, Farzin Kazemi
Abstract
This study introduces synchronized double-stage yield buckling-restrained brace (SDY-BRB) characterized by high post-yield stiffness, aiming to enhance control of structural responses. The SDY-BRB incorporates a parallel low yield point (LYP) steel plate and high-strength steel (HSS) tube confined within a restrainer unit. The strategic utilization of these cores at distinct loading stages facilitates a double-stage working mechanism, partial self-centering behavior, and excellent energy dissipation capacity. A detailed description of the fundamental configuration, operational principle, key design parameters, and a simplified hysteretic model is presented. Subsequently, a comprehensive numerical investigation is conducted, encompassing diverse models with varying design parameters. The analysis evaluates cyclic responses, including hysteretic behavior, energy dissipation , and pertinent mechanical indices. Furthermore, the seismic investigation is extended to a structural level to assess the influence of critical parameters on the overall structural response. To this end, nonlinear time history analyses are performed on benchmark models of 3-, 6-, and 9-story steel braced frames . These models consider scenarios involving conventional buckling-restrained braces (BRBs) and SDY-BRBs subjected to different seismic hazard levels. The results demonstrate that the SDY-BRB exhibits satisfactory seismic behavior , confirming the anticipated sequential yielding mechanism. It is observed that the rational design of the SDY-BRB can effectively suppress peak and, more importantly, residual inter-story drift within the structure.