方钢管混凝土柱-H型不等高钢梁框架节点抗震性能试验研究

Experimental study on seismic behavior of joints in the frame with concrete-filled steel square tubular column and H-shaped unequal height steel beam

为了研究方钢管混凝土柱-H型不等高钢梁框架节点的抗震性能,基于现行规范按缩比1∶3设计并制作了4个方钢管混凝土柱-H型不等高钢梁外加强环式框架节点模型,对其进行拟静力加载试验,以梁高差为参数,研究该类节点的滞回曲线、延性、强度与刚度退化、耗能性能。试验结果表明:4个试件的破坏均发生在梁端,节点核心区均没有破坏,满足"强剪弱弯、强节点弱构件"设计要求;所有试件的滞回曲线均有捏缩现象,呈弓形;节点在反向加载时的承载力要高于正向加载时的承载力,且随着梁高差的变化,试件破坏形态有所不同;该类节点强度衰减、刚度退化明显;4个试件的延性系数为3.956~4.388,能量耗散系数为1.383~1.811,等效黏滞阻尼系数为0.220~0.288,说明该类节点具有较强的耗能能力,但随着左右梁高差的增大,耗能能力逐渐降低。

In order to study the seismic behavior of joints in the frame with concrete-filled square steel tubular columns and H-shaped unequal height steel beam, based on the current specifications, four outer ring frame models with concrete-filled square steel tubular column and H-shaped unequal height steel beam were designed and fabricated according to the reduction ratio of 1∶3. And the pseudo-static loading test was carried out. The hysteresis curve, ductility, strength and stiffness degradation and energy dissipation performance of the nodes were studied with the beam height difference as the parameter. The test results show that the damage of the four specimens occurs at the beam end, and there is no damage in the core area of the joint, which satisfies the design requirements of "strong shear weak bend and strong joint weak component";the hysteresis curves of all test pieces have pinch phenomenon and bow shaped. The arch bearing capacity of the joint is higher than that of the forward loading, and the deformation modes of the specimens are different with the variation of the beam height;the strength attenuation and stiffness degradation of the joint are obvious. The ductility coefficients of the four specimens are 3.956~4.388, the energy dissipation coefficient is 1.383~1.811, and the equivalent viscous damping coefficient is 0.220~0.288, indicating that the nodes have strong energy dissipation capacity. But with the increase of differences in the left and right beam heights, the energy consumption gradually decreases.