火灾下钢管混凝土柱与钢梁外伸端板连接的力学性能

Mechanical Performance of Extended End Plate Connections with CFST Columns in Fire

为了研究钢管混凝土框架梁柱半刚性连接的抗火性能,利用ABAQUS软件进行了火灾作用下钢管混凝土柱与钢梁外伸端板连接节点的热力耦合性能的数值模拟。确定了高温下钢材和核心混凝土的材料本构关系模型,建立了考虑楼板影响的钢管混凝土框架外伸端板连接节点的有限元计算模型,对三面受火和外荷载共同作用下节点的受力全过程进行了分析。详细分析了荷载比、螺栓预紧力、防火保护层厚度、材料特性、构件几何尺寸等参数对节点耐火极限的影响。结果表明,荷载比、螺栓预紧力、防火保护层厚度和钢梁截面高度对组合节点耐火极限的影响较显著。该研究结果将为火灾下半刚性钢管混凝土框架的设计理论提供科学依据。

To obtain the fire resistance of beam-to-column semi-rigid joints for CFST frames, a numerical analysis of the thermal mechanical coupling behavior of extended end plate joints between CFST columns and steel beams in fire was done. The constitutive models of steel and core concrete material at high temperature were determined. The nonlinear finite element modeling of extended end plate joints to CFST columns was made considering the floor effect. The full process analysis of the typed connections under three-face fire and loading was carried out. The effects of load ratio, bolt pretightening force, fire protection layer thickness and material properties, geometry dimension of the main parameters on the fire resistance of the joints were studied. The research results show that the load ratio, the bolt pretightening force, the fire protection layer thickness and the dimensions of the steel beam significantly affect the fire resistance of com- posite joints. It provides the scientific basis of the design theory of semi-rigid CFST frames in fire.