加强环式钢管混凝土框架节点计算模型的研究

在分析加强环式连接的钢管混凝土框架时,一般采用刚性框架分析法,把节点假设为完全的刚性连接。然而这种假设并不符合实际。通过两层两跨的框架静载试验,研究了节点核心区的剪切变形,并测量了框架的水平荷载-侧移曲线,以验证本文的节点计算模型的准确性。试验发现弹性阶段节点核心区的剪切刚度很大,对框架变形的影响可以忽略不计。借助有限元分析软件ANSYS建立框架有限元模型,采用了一种新的节点计算模型,即用弹簧单元和刚性单元来分别模拟梁柱连接和节点核心区,弹簧刚度由文献[6]的M-θ公式确定。将本文方法及其它分析方法得到的水平荷载-侧移曲线与框架试验结果进行比较,证明了本文的方法比传统的刚性框架分析法及其它方法,更加准确地反映了框架弹性阶段的受力性能。

Research on analytical model of joint in concrete-filled steel tubular frame with stiffening ring

When analyzing concrete-filled steel tubular(CFST) frames with stiffener ring plates,the rigid-frame analytical method is often used with assuming full-rigid joints.However the assumption does not agree with the fact.To study the shear deformation in the core region of joint and measure the level load-top displacement curve of the frame to prove the accuracy of the calculating model of joint proposed by the authros,this paper carried out the static experiment of the two-story and two-span CFST frame with stiffener ring plates.It was found that the core region of joint was shearing-rigid on elastic stage and its influence on the deformation of frame could be neglected.Then the paper built the finite element model of the frame with ANSYS and used a new calculating model of joint which used rigid elements to model the core region of joints and used spring elements,whose stiffness was calculated by the M-θ formula in the sixth reference paper,to model the beam-to-column connections.Finally the level load-top displacement curves calculated by the authors′ method and other method were compared with the test results.It proved that the authors′ method predicted the frame behavior on its elastic stage more accurately than the traditional method and other methods.