Seismic performance of self-centering multistage buckling restrained brace

AbstractThe all-steel self-centering multistage buckling restrained brace (SC-MBRB) with restrained cores consisting of different steel grades is an innovative hybrid system introduced to elevate the performance of conventional BRBs. This study submits a new configuration of SC-MBRB with cores made of high-strength (HSS), ultra-high-strength (UHSS), and low yield point (LYP) steels. A trilinear hysteretic model is proposed to simulate the cyclic behavior of SC-MBRBs. The seismic performance of SC-MBRB, including cyclic response, energy dissipation, re-centering property, and plastic deformations, was investigated by finite element (FE) analysis. Considering the specification of HSS and UHSS, including fracture behavior, low cycle fatigue, and ductility, the effect of different ratios of strength and cross-sections was investigated. Eventually, models with varying core lengths whose specifications were determined based on the Coffin-Manson relationship were examined. The results indicate that the introduced SC-MBRB has provided suitable seismic performance. Moreover, the trilinear kinematic hysteretic model could successfully predict the hysteretic behavior of SC-MBRB. Furthermore, applying maximum HSS core length with minimum LYP core length and combining S960 with the LYP100 provides the most reliable results.