高强方钢管轻骨料混凝土桁架加劲搭接K形节点承载力研究

对高强方钢管轻骨料混凝土桁架加劲搭接K形节点和基本型节点进行主管轴压静力加载试验, 考察了支管搭接率和加劲板构造对节点受力性能的影响. 试验结果表明: 节点的破坏模式为支管根部侧面搭接焊缝开裂; 支管搭接率过大或过小均会降低搭接K形节点承载力; 加劲节点的屈服荷载和极限荷载较基本型节点分别提高6.5％和12.0％. 同时, 对高强方钢管轻骨料混凝土桁架加劲搭接K形节点进行了数值模拟、热点应力场演化分析和破坏机理探究, 推导了极限承载力计算式. 通过与节点试验结果对比, 验证了该计算式的精度.

Bearing capacity of lightweight aggregate concrete-filled high strength square steel tube truss with stiffened lapped K-joint

In order to study the effect of braces lap ratio and stiffening plates on the performance of lightweight aggregate concrete-filled high strength square steel tube truss with lapped K-joint, static loading tests under axial compression were performed on stiffened lapped K-joints and traditional lapped K-joint. Tests results show that crack of lapped weld between braces is the typical failure mode of the lapped K-joint. Too large or too small overlap ratio can reduce the bearing capacity of the lapped K-joint. The yield load and ultimate bearing capacity of the stiffened lapped K-joint increase by 6.5％ and 12.0％ respectively compared with those of the traditional lapped K-joint. The numerical simulation, hot spot stress evolution and failure mechanism analysis of the lapped K-joints were also carried out. The formula for calculating the ultimate bearing capacity of the lapped K-joint was proposed. Compared with the test results, the accuracy of the proposed formula for calculating the ultimate bearing capacity of the lapped K-joint was verified.