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

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

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.

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.