Design, analysis and application of the double-stage yield buckling restrained brace

Abstract

Traditional buckling restrained brace provides a dual-function of elastically resisting lateral forces under frequent earthquakes and plastically dissipating seismic energy under rare earthquakes. A new Double-stage Yield Buckling Restrained Brace (DYBRB) of cross shape is proposed and verified by experiment in this paper. It will partially enter the yield state under frequent earthquakes, dissipating seismic energy and providing stiffness for the main frame structure simultaneously, and further increasing the energy dissipation capacity under rare earthquakes. The mechanism of double-stage energy consumption is explained by the structural design scheme and the hysteretic curves, and it's basically consistent with the experimental results. Three key parameters consist of the length ratio of yield section, the strengthening ratio of strengthened section, and the bearing capacity ratio of yield section. The mechanical properties of DYBRB are analyzed theoretically, and the optimal values of the key parameters are given by the hysteretic curves of DYBRB. Finally, a frame structure with DYBRBs is demonstrated to resist the seismic damage. Results show that if the length ratio of yield section ranges in 0.35–0.5, the strengthening ratio of strengthened section is between 2–4, and the bearing capacity ratio of yield section is 1.0. DYBRB can achieve the best double-stage yield effects and have the significant energy dissipation. The frame structure equipped with DYBRBs is compared with the structure with traditional BRBs, and the undamped building. The former design has a better seismic energy dissipation capacity than the latter two schemas under different earthquakes.