变电站钢管塔架多支管空间节点受力性能研究

以青海佑宁750kV变电站塔架的复杂节点为背景，对两类空间多支管梁、柱节点进行了静力加载试验和非线性有限元分析。试验中采用足尺模型，试验装置为具有足够刚度的自平衡框架，制作梁、柱节点试件各2个，采用主动与被动加载相结合的试验加载方案。试验得到了节点的破坏模式、荷载 位移曲线、荷载 应变曲线及受力特性。在此基础上，建立了复杂节点的非线性有限元模型，并对节点的承载性能进行了分析。结果表明：主管部分属于节点的薄弱部位，两类节点都发生了主管凹曲变形破坏，且未出现支管和焊缝的破坏；另外，梁节点两试件出现了支管插板及其加劲板的受压弯曲破坏；加载至设计荷载值时，两类节点所有测点基本处于线弹性工作状态，且节点承载力富余较大，表明节点设计较安全。参数分析表明，主管径厚比 γ 对节点承载力影响显著，支主管直径比β₂及厚度比 τ₂对节点承载力具有一定影响；梁节点中，γ较小时，β₇对节点承载力影响较大；β₄、τ₄、β₅节点板与主管厚度比τ_J及插板与主管厚度比τ_c对各自节点承载力基本无影响。

Mechanical performance of multiplanar space joints ofsubstation tubular tower

The behavior and bearing capacity of two type multiplanar tubular beam and column joints were investigated via test under static loading in equal proportion and nonlinear finite element analysis, with the background of Youning 750kV transformer substation engineering in Qinghai. Four full-scale specimens, test instrument of self-balancing frame with sufficient stiffness and test scheme of active and passive load were presented. Through analyzing the test results, the failure mode, load-displacement-curve, load-strain curve, and mechanical performance of the joints were obtained. On this basis, the nonlinear finite element models were established and analysis for the complicated joints. The research indicates that the main pipe is a weak part of two type joints, and the concave deformation occurs in their main pipes with no failure in branch ones or welds. In addition, the flexural failure of the flapper and flapper’s stiffener of branch pipe by pressure appears in the beam joints. All measuring points of two type joints are basically kept in linear elastic condition under design loads, and design of joint is very safe with big ability. The results of parametric analysis show that the parameter chord radius to thickness ratio γ has a significant influence on the bearing capacity. Brace to chord diameter ratio β₂ and thickness ratio τ₂ have some influences on the maximum intensity. β₇ has higher impact on the limit strength for small γ value in the beam joints. β₄、τ₄、β₅ gusset plate to chord thickness ratio τ_J and inserting plate to chord thickness ratio τ_c have no impact on the bearing capacity.