Abstract: To study the seismic performance of buckling-restrained braces (BRBs) and the corresponding system at high temperatures (i.e., concerning fire), the mechanical properties of the BRB core material were tested at room and high temperatures. Considering the test results, a refined thermomechanical coupling finite element model of a BRB was established and the accuracy of the model was verified. Additionally, the performance of temperature field, hysteretic curves, skeleton curves, and energy dissipation capacity of an LYP160 BRB under conditions resembling fire were compared and evaluated. Elasto plastic dynamic time analyses were separately conducted regarding a BRB with an 8-story steel frame structure (labeled as BS) and the original structure (OS) under various conditions: three high-temperature ranges (like fire) and room temperature. The results showed that the average inter-story drifts of the BS under the three heat conditions were 30.4%, 33.2%, and 42% lower than that of the OS. There are severe damage of plastic hinges on the OS, more occurring in the column, while the overall damage of BS was less severe. Thus, the BS is safer and more stable than the OS.

Key words: buckling-restrained brace, low-yield-point steel, ?re, ?nite element, seismic performance