不同构造钢板装配式屈曲约束支撑性能试验研究

设计5个钢板装配式屈曲约束支撑（Buckling-Restrained Brace, BRB）试件，对其进行低周反复试验，研究无黏结材料、约束比和加载制度等对其力学性能的影响。结果表明：无黏结材料能有效减小外约束单元与核心单元之间的摩擦力，设置无黏结材料的屈曲约束支撑滞回曲线对称、饱满，耗能性能稳定，有较强的抗疲劳能力；设置无黏结材料钢板装配式屈曲约束支撑等效黏滞阻尼比曲线呈现两阶段双线性的特征；约束比小于1的钢板装配式屈曲约束支撑发生整体屈曲失稳；先压后拉和先拉后压的加载方式对屈曲约束支撑滞回性能基本没有影响；基于屈曲约束支撑先于主体结构屈服和不发生因塑性能力不足而提前破坏的设计原则，工程设计中建议屈曲约束支撑延性系数μmax＞13，累积塑性变形CPD＞1200。

Experimental study on hysteretic performance of steel-plate assembled buckling-restrained braces with different constructional details

The mechanical characteristics of five steel-plate assembled buckling restrained braces (BRBs) were compared. Different design parameters, such as the constraint ratio, the loading schedules, and the unbounded materials, were considered in the low cyclic reversed loading tests. The experimental results indicate that the unbounded materials can be used to reduce the friction force between the external constraint units and the core units. The BRB with unbounded materials demonstrates a full hysteresis loop, stable energy-dissipated capacity and substantial anti-fatigue properties. The steel-plate assembled BRB with unbounded materials exhibits a bilinear curve of the equivalent viscous damping ratio with its axial deformation. The BRB with the constraint ratio less than 1 is unstable with overall buckling. The loading schedules show little influence on the hysteretic performance of the BRB. Since the BRB should yield before the main structures, and early failure of BRBs due to inadequate plastic deformation capacity should be avoided, μmax is suggested larger than 13 and CPD should be no less than 1200 in the engineering practice.