开槽式三重钢管防屈曲耗能支撑试验研究

Experimental study of notch-type triple-steel buckling-restrained braces

基于"核心单元局部削弱相当于其他部位加强"的新型防屈曲耗能支撑设计原理,设计了开槽式三重钢管防屈曲耗能支撑和普通三重钢管防屈曲耗能支撑,对7个支撑构件在轴向循环往复荷载作用下的性能进行了拟静力试验研究和有限元模拟分析,研究开槽式三重钢管防屈曲耗能支撑的滞回性能、恢复力模型、破坏特征以及不同开槽数量对支撑性能的影响情况。研究结果表明:开槽式三重钢管防屈曲耗能支撑在受拉和受压时都能屈服而不屈曲,其轴力-位移滞回曲线稳定、饱满,对称性和规律性好;开槽式支撑的屈服荷载和屈服位移小于不开槽支撑,具有提前屈服的功能,开槽不影响支撑的整体承载力,开槽式支撑的恢复力模型可以采用对称的双线性恢复力模型来描述;开槽可以使支撑的薄弱部位从核心钢管端部转移到开槽部位,使支撑具有定点屈服的功能,避免了支撑端部破坏。

This paper presents a new design of notch-type triple-steel-tube buckling-restrained brace（TST-BRB）,based on the philosophy of ＂partially weaken the core element of the buckling-restrained brace to protect the other part of the brace member＂.Seven buckling-restrained brace（BRB） members was prepared and the experiments as well as numerical analysis were carried out to study the hysteretic energy dissipation performance,restoring force model,and failure characteristics of the BRB members,as well as the effects of the design parameters to the performance of the notch-type BRB.The results indicate that the hysteretic curve of the proposed BRB was stable,full and symmetric.The yield displacement and yield stress of the non-notched specimen were more than that of the notched specimens,but the bearing capacity of the BRB was not affected,and that the restoring force of the proposed BRB can be described by a bilinear model.Another advantage of using the notches in the design of BRB is that it prevents the end elements from buckling so that it is not necessary to strengthen the ends of the core element of the BRB.Therefore,it substantially simplifies the fabrication process of BRB and also results in material savings.