Seismic design, nonlinear analysis, and performance evaluation of recentering buckling-restrained braced frames (BRBFs): Fid-Bau Portal

Seismic design, nonlinear analysis, and performance evaluation of recentering buckling-restrained braced frames (BRBFs)

Hu, Jong-Wan / Choi, Eunsoo

Abstract Buckling-restrained braced frames (BRBFs) have been increasingly used as seismic-load resisting systems in the area of high seismicity due to the fact that their performance is far superior to that of concentrically braced frames (CBFs). The buckling-restrained brace (BRB) members have inherent ability to yield under both tension and compression without buckling, but large strains that can make entire frame structures more prone to permanent deformation intensively occurs at the end support connector. This dilemma can be solved applying auto-restoration capability to this part of the bracing member. For this reason, this study suggests a methodology that incorporates recentering systems obtained by utilizing superelastic shape memory alloys (SMAs) into buckling-restrained braces (BRBs). The superelastic SMAs recover original configuration without heat treatment even after experiencing large deformation. Analytical frame models are developed to evaluate the BRBFs with respect to peak and residual inter-story drifts. The analytical findings demonstrate that, compared to frames with conventional steel bracing systems, the BRBFs with superelastic SMA bracing systems are able to reduce residual inter-story drifts more effectively during earthquake events due to the self-healing characteristics of such SMA materials.