钢管多支管构架柱节点承载力研究

以750kV输电塔架工程的复杂节点为背景，对其空间多支管柱节点承载力进行了试验研究和理论分析。试验采用2个足尺试件模型，在自平衡框架内完成，采用主动与被动加载相结合的方案。试验得到了节点的破坏模式、荷载-应变曲线及受力特性。在此基础上，利用虚功原理和圆环-母线梁模型建立了节点的承载力理论分析模型，给出了估算节点极限承载力的计算公式。研究结果表明：节点发生了主管凹曲变形的破坏，且未出现支管和焊缝的破坏；理论模型能够较准确反映节点局部屈服时塑性铰的发展，使节点复杂的受力状态得以简化，且理论分析方法考虑了空间支管的共同作用，所得计算结果及节点破坏特征与试验、有限元结果较接近，该理论模型具有一定的适用性。

Study on bearing capacity of multiplanar column joints in steel tubular frame

The ultimate capacity of a new type multiplanar tubular column joints were investigated via test under static loading and theory analysis, with the background of 750kV transmission tower engineering. Two full-scale test specimens, test instrument of self-balancing frame with sufficient stiffness and test scheme of active and passive load were presented in detail. Failure mode, load-strain curve, and mechanical performance of the experimental joints were obtained through analyzing the test results. Based on the experimental results, the theory analysis model was established and the calculation formulas of the ultimate strength of space joints determined were given by the principle of virtual work and the ring-generator separation model. The research indicates that the concave deformation occurs in the main pipes with no failure in branch ones or welds. In addition, the development of plastic hinges with local yield theoretical model can be accurately reflected and the complex stress state can be simplified considering the interaction of space branches. Compared with the experimental and finite element analysis results, the calculated ones are reasonable and the theoretical model has applicability.