部分包裹混凝土柱端板连接框架抗震性能研究

Seismic behavior of partially encased concrete composite column steel beam frame with end plate connection joints

为了研究部分包裹混凝土柱-型钢梁端板连接半刚性框架的抗震性能,选取柱翼缘厚度及端板厚度作为参数设计了3榀框架,对其施加恒定竖向荷载及低周反复水平荷载,并进行有限元模拟.分析框架的破坏机理、滞回性能、刚度退化等抗震性能指标,了解节点的破坏形态.研究结果表明:框架主要破坏形态是梁端翼缘屈服,出现塑性铰,柱脚屈服,端板破坏不明显;节点域混凝土出现45°斜裂缝,柱腹板主应力方向在45°左右,核心区混凝土及柱腹板可以简化为45°斜压杆模型.柱翼缘厚度由12 mm增至18 mm,框架承载力增加13.94%;端板厚度由14 mm增至18 mm,框架初始刚度提高约9.74%.部分包裹混凝土柱-型钢梁端板连接框架结构具有较高的承载力、耗能能力和延性,适合地震区应用.

In order to study the seismic performance of the partially encased concrete composite column-steel beam semi rigid frame with end plate,three frames were designed by selecting the thickness of the column flange and the end plate as parameters,on which a constant vertical load and a low cycle repeated horizontal load were tested and finite element simulation was carried out.The seismic performance indexes as failure mechanism,the hysteresis curve,the stiffness degradation and the damage form of node were analyzed.The results show that the beam end flange yield,the formed plastic hinge and yield in column bottom were the main damage in framework.There were shear oblique cracks appearing at 45°on the node domain concrete,and the end plate damage was not apparent.The principal stress direction of column web is about 45°,and the concrete and column web in the core area can be simplified to the 45°baroclinic bar model.The column flange thickness increased from 12 mm to 18 mm,and the frame bearing capacity was increased by 13.94%.The end plate thickness increased from 14 mm to 18 mm,and the initial stiffness of frame increased by about 9.74%.The partially encased concrete composite column-steel beam semi rigid frame with end plate possessed higher bearing capacity,energy dissipation capacity and ductility,which is suitable for the application in seismic regions.