二阶段屈服方形截面防屈曲支撑设计方法及受力性能

Design method and mechanical behavior of square section buckling restrained brace with two yield stages

提出一种二阶段屈服防屈曲支撑,其屈服位移较小,可在主体结构破坏前率先屈服并耗散地震能量,保护主体结构。首先,建立该新型支撑的力学模型,并推导屈服承载力、屈服位移和轴向刚度计算公式,提出该支撑的各种破坏模式及设计流程。对2组共6个试件进行静力往复加载试验,证明该支撑具有良好的滞回性能和延性,并验证计算公式的可靠性。最后,与传统防屈曲支撑性能指标进行相比。研究结果表明:两类支撑具有近似的屈服承载力,但二阶段屈服防屈曲支撑具有更大的弹性刚度和更小的屈服位移。工程设计中修改支撑的设计参数可改变其屈服位移,使其较早发生屈服并耗散地震能量,起到保护主体结构的作用。

A novel buckling restrained brace with two yield stages was proposed, which is able to yield and dissipate earthquake energy before the damage of the main structure component. Firstly, the mechanical model of the novel buckling restrained brace was established, and the equations of the yield capacity, the yield displacement and axial stiffness were deduced, and the failure modes and the design process of the novel brace were proposed. A total of 6specimens in 2 groups were tested by static reciprocating loading experiment, showing that the novel braces perform good hysteretic performance and ductility, and verify the reliability of the equations recommended. Finally, the performance comparison with traditional buckling constraint brace was carried out. The results show that the yield capacities of the two types of braces are close, but the novel brace with low yield displacement performs the larger elastic stiffness and the smaller yield displacement. The yield displacement of the novel brace can be changed by modifying the design parameters of the brace, and the novel brace would dissipate the earthquake energy earlier and protect the main structure when a small yield displacement arrives.