Analytical and experimental studies on budding-restrained brace with gap-supported tendon protection

摘要

This paper proposes a new brace called TP-BRB, composed of a conventional buckling-restrained brace (BRB) with a gap-supported tendon protection (TP) in parallel. The gap-supported tendon protection remains inactive before the deformation of TP-BRB reaches a threshold value, while obtaining a high axial stiffness after the threshold value is exceeded. Under strong earthquake, the TP-BRB is expected to provide structures with effective energy dissipation capacity and mitigate the risks of global collapse caused by low post-yield stiffness of the conventional BRB. As the earliest part of the research on the TP-BRB, this paper firstly presents both the stiffness characteristics of the hysteretic curve and a theoretical formula of residual deformation. Secondly, a quasi-static test is conducted, the results of which illustrate that TP-BRB shows a stable hysteretic behavior, a skeleton curve with significant tri-linear characteristic, and a smaller residual deformation than a conventional BRB. Finally, parametric studies based on numerical models show that, with the reduction of the threshold value (u(0)) and the increase of the ratio (I) between the axial stiffness of BRB and gap-supported tendon protection, both the residual deformation and the equivalent damping ratio of TP-BRB decrease, but the secant stiffness of TP-BRB increases. (C) 2019 Elsevier Ltd. All rights reserved.