Enhancing seismic resilience in steel frames with synchronized double-stage yield buckling-restrained braces

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. • A novel synchronized double-stage yields BRB (SDY-BRB) is introduced. • The impact of SDY-BRB design parameters on overall structural response is analyzed. • The hysteresis behavior of SDY-BRB is studied. • SDY-BRB offers high post-yield stiffness and good energy dissipation. • SDY-BRBs improve seismic performance compared to conventional BRBs.