The composite truss joint is the key of the truss. A static experiment is done on 3 steel-concrete composite truss joints models with PBL connectors to study the ultimate bearing capacity, modes of failure and failure mechanism of the composite truss joint. A FEA model of composite joint is set up. The experiment results show that failure mechanisms include the cracking of concrete, local buckling on the steel plate, bolt slip of tension brace, stress concentration on connecting region of the steel and concrete. The FEA results agree well with the experiment, and the PBL connector has a good ability of shearing resistance. The FEA model also shows the joint's capacity can be effectively improved by increasing the thickness of plate. Finite element analysis and experiment results provide a theoretical reference and basis for the joint application in engineering practice.%外接式钢-混凝土组合端节点是组合桁架结构受力的关键部位.通过对3个采用PBL连接件的外接式钢-混凝土组合桁架节点的单调静力试验,研究节点的极限承载力、失效模式和破坏机理.应用有限元软件ANSYS对试件进行全过程数值模拟分析.试验结果显示:节点的失效模式有混凝土开裂破坏、外露节点板局部屈曲、受拉腹杆处螺栓滑移及钢-混凝土连接部位应力集中.计算结果与试验结果吻合良好,PBL连接件具有较好的抗剪能力.通过增加节点板厚可有效提高节点承载能力.计算及试验结果可为该节点在工程实践中的应用提供理论依据和试验参考.
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