Numerical evaluation of cyclic and seismic performance of three-core buckling-resistant braces with partially re-centering properties

Recent studies have demonstrated the enhanced seismic performance of structures incorporating dual-core buckling-resistant braces (DC-BRBs) utilizing materials with distinct yield strengths. This research introduces a novel three-core BRB (TC-BRB) featuring partially re-centering characteristics, assembled from diverse metallic constituents. Initially, the TC-BRB configuration is delineated, followed by a numerical investigation employing finite element analysis to ascertain the factors influencing its cyclic behavior, encompassing hysteresis curves, cumulative energy dissipation, and re-centering properties under cyclic loading. High-strength steels (HSS), structural steels, and low-yield point (LYP) steels were employed as TC-BRB cores. Furthermore, an examination of parameters affecting TC-BRB behavior was conducted by incorporating cores with variable lengths and cross-sections. Subsequently, by integrating the proposed brace into 4- and 8-story structural systems and subjecting them to two hazard levels, namely, the design base earthquake (DBE) and maximum considered earthquake (MCE), the seismic response of these structures was assessed through nonlinear dynamic and incremental dynamic analysis. Additionally, fragility response curves were generated and compared for the investigated structures. The findings revealed that the cyclic behavior of TC-BRBs, characterized by desirable multi-stage characteristics, contributes to a reduction in structural responses, including inter-story drift ratio (IDR), residual drift ratio (RIDR), and peak floor acceleration (PFA), within the studied systems. Moreover, while achieving higher performance levels, the probability of collapse was diminished.