含屈曲约束连接件的钢框架节点抗震性能研究

A study on seismic performance of steel frame joints with buckling-restrained connectors

基于屈曲约束和损伤控制的思想,提出了一种含屈曲约束连接件的钢框架节点,连接件的一对核心板传递翼缘轴力并平衡梁端弯矩,对核心板设置了由约束板、填充板和梁外伸翼缘组成的屈曲约束系统。对有无设置约束板的两个试件进行了低周往复荷载试验,分析了节点的滞回曲线、骨架曲线、能量耗散和应变分布,考察了约束板对节点滞回性能的影响;采用有限元软件ABAQUS对该节点进行了数值模拟,研究了核心板螺栓和厚度对该节点滞回性能的影响。结果表明:提出的节点可以达到预期的屈曲约束和损伤控制机制,即核心板率先屈服耗能,约束板可防止核心板发生过大的面外屈曲,主体梁柱保持弹性,节点具有稳定的滞回性能和较大的变形能力;核心板上螺栓预紧力决定了核心板是否会滑移,进而影响滞回曲线的饱满程度,核心板厚度主要影响节点刚度、承载力和损伤分布。最后,理论推导了节点的承载力和变形计算公式,给出了节点理论骨架曲线。

Based on the ideas of buckling restraint and damage control, a steel frame joint with a buckling-restrained connector was proposed in this paper. A pair of core plates of the connector, for which a bucking-restrained system consisting of a restraining plate, two filling plates and an extending beam flange was set up, transmits flange axial forces and balances the beam end moment. Two specimens with and without the restraining plate were tested under low-cyclic loads, and the hysteresis curve, skeleton curve, energy dissipation and strain distribution were analyzed to investigate the influence of the restraining plate on the hysteresis performance of the joints;numerical simulations of the joints were conducted using the finite element software ABAQUS to study the influence of the core plate bolts and thicknesses on the hysteresis performance of the joints. Results show that the proposed joint can achieve the expected buckling restraint and damage control mechanism, i.e., the core plate first yields to dissipate energy, the restraining plate can prevent excessive out-of-plane buckling of the core plate, the main beam and column remain elastic, and the joint behaves a stable hysteresis performance and large deformation capacity. The bolt preload on the core plate determines whether the core plate will slip, which in turn affects the fullness of the hysteresis curve;the core plate thickness mainly affects the joint stiffness, bearing capacity and damage distribution. Finally, the formulae of bearing capacity, beam end displacement and skeleton curve of the joint were theoretically determined.