基于不同构造形式半刚性节点的人字形中心支撑钢框架低周往复荷载试验研究

Low-Cyclic Reversed Loading Tests of Chevron Concentrically Braced Steel Frames with Semi-rigid Connections of Different Details

为研究装配式中心支撑半刚接钢框架结构的抗震性能,选取三种便于装配化施工的半刚性梁柱螺栓节点,即带腹板耳板的顶底角钢连接、外伸端板连接和T形钢连接,设计了3榀人字形中心支撑半刚接钢框架试件,进行低周往复荷载试验,对结构的滞回曲线、承载能力、耗能性能和刚度退化进行了研究,并对比分析不同半刚性节点钢框架的性能优劣。试验结果表明:试件滞回曲线饱满,抗侧承载力高,具有稳定可靠的耗能性能和塑性变形能力;结构在水平往复荷载作用下有明显的屈服和破坏过程,整体呈现延性破坏的特征;结构的塑性变形和损伤破坏主要集中在支撑体系,钢框架梁、柱残余变形小,半刚性节点没有产生塑性变形,结构具有两道抗震防线;半刚接钢框架和中心支撑体系协同工作性能良好;经综合对比分析结构采用外伸端板连接时具有较优良的抗震性能。

To investigate the seismic behavior of prefabricated steel concentrically braced frames with semi-rigid connections, three types of semi-rigid bolted connections for prefabricated construction, including the top-and-seat angle connection with web ear plate, extended end-plate connection and T-stub connection, are selected.Three steel concentrically braced frames with the connections are designed and then tested under low-cyclic reversed loading to study the hysteretic curves, bearing capacity, energy dissipation capacity, rigidity degradation.Also, a comparative analysis of the specimens is conducted to study their advantages and disadvantages.The test results demonstrate that the specimens possess plump hysteretic curves and high bearing capacity, as well as stable energy dissipation capacity and inelastic deformation capacity.The specimens show a clear yielding and failing process under low-cyclic reversed loading, which makes the specimens exhibit a ductile failure behavior.The inelastic deformation and damage to the specimens concentrate on the bracing system, and the beams and columns only have a small residual deformation.The semi-rigid connections remain in elastic stage, and thus the specimens have two seismic defense lines.The steel frame and braces show a good cooperative working behavior.The structure can have more excellent seismic behavior when using extended end-plate connections based on a comprehensive comparison.