新型自复位方钢管混凝土框架的抗侧刚度研究

Study on lateral stiffness of new type self-centering concrete filled square steel tubular frame

提出一种新型绕梁腹板销轴转动的自复位方钢管混凝土框架梁柱连接节点.推导了自复位方钢管混凝土框架的抗侧刚度计算公式,通过有限元分析验证了公式的正确性.研究了钢绞线截面面积和初始预应力大小对自复位方钢管混凝土框架自复位能力的影响,探明了自复位框架的失效机制.结果表明:自复位方钢管混凝土框架具有良好的自复位能力,框架构件保持弹性.随着钢绞线截面面积增大,自复位框架刚度和承载力增大;钢绞线处于弹性时,初始预应力大小对自复位框架刚度影响很小.初始预应力合理取值可避免自复位框架失效机制的发生,并给出了初始预应力取值范围.

A new type self-centering beam-column joint rocking about the pin roll located in the centerline of the beam web is proposed for concrete filled square steel tubular （CFSST） frame. The lateral stiffness calculation formula of the self-centering CFSST frame was derived from the virtual work principle. The formula was verified by finite element analysis. The influences of the section area of strands and initial prestress on the self-centering ability of CFSST frame were studied. The failure mechanism of the self-centering frame was determined. The results show that the self-centering CFSST frame has good resilience, and the frame ele- ments remain elastic during the rotation. With the increase of the section area of strands, the stiffness and bearing capacity of the self-centering CFSST frame increase. The initial prestress of strands has little effect on the lateral stiffness of self-centering frame when the strands are elastic state. The failure mechanism of the self-centering frame can be prevented by the reasonable value of initial prestress. The recommended value range of initial prestress is proposed.