腋撑式半刚性钢框架抗侧性能试验与设计方法研究

Experimental study on lateral resistance behavior of semi-rigid steel frames with knee braces and design method

对1个梁柱半刚性连接的钢框架试件和4个梁柱腋撑式连接的半刚性钢框架试件进行侧向循环加载试验,基于各试件的荷载-位移曲线对其侧向刚度、承载力、延性和耗能能力等抗侧性能指标进行研究,总结了5个试件的典型破坏模式,分析了增设的腋撑、腋撑截面大小和梁柱连接的转动刚度等因素对钢框架抗侧性能影响。考虑腋撑与梁柱半刚性连接的协同作用,建立腋撑式钢框架的三种屈服机制,提出该类框架在不同屈服机制下的抗侧刚度理论计算与设计方法。采用ABAQUS有限元软件对试验进行模拟分析,试验结果验证了有限元模型的适用性。采用校核后的有限元模型建立了15个考虑不同参数的腋撑式框架模型,验证了所提出理论计算方法的适用性。研究结果表明:装配式腋撑能有效提高半刚性钢框架的初始抗侧刚度、承载力和耗能能力,延性和变形能力略有下降,与腋撑螺栓连接的梁下翼缘最外侧螺孔为该类型框架的薄弱部位。

A semi-rigid steel frame and four semi-rigid steel frames with knee braces were designed and tested under lateral cyclic loading.Based on force-displacement curve,the lateral stiffness,bearing capacity,ductility and energy dissipation capacity of each specimen were investigated.The typical failure modes of five specimens were summarized.The influences of additional knee braces,section size of knee braces and rotation stiffness of beam column connection on the lateral performance of semi-rigid steel frame were analyzed.Considering the corporate effect of semi-rigid connection and knee braces,3 different yield mechanisms with considering gravity load were established.The theoretical calculation and method of lateral stiffness without considering gravity load under different yield mechanisms were proposed.The finite element analysis(FEA)of the test was conducted by software ABAQUS and verified against the experimental results.Furthermore,a total of 15 FEA models considering different parameters were established to verify the accuracy of the theoretical calculation.The results show that the fabricated knee braces can effectively improve the initial lateral stiffness,lateral bearing capacity and energy dissipation capacity of semi-rigid steel frames,while the ductility and deformation capacity decrease slightly.The screw hole at the outermost flange of the beam bolted to the knee brace is the weak part of this type of frame.