双角钢组合截面构件在往复弯曲下的恢复力模型研究

Study on restoring force model of double-angle built-up members under cyclic bending

为建立延性交错桁架钢框架结构双角钢组合截面弦杆在往复弯曲下的恢复力模型,对6个双角钢组合截面足尺试件进行了低周往复加载试验,研究了填板间距及加劲肋布置对构件滞回性能的影响.通过对试验数据的回归分析,得到了试件的骨架曲线及刚度退化规律,确定了双角钢组合截面弦杆的恢复力模型,其骨架曲线为弹性阶段、强化阶段和承载力退化阶段组成的三折线模型.最后,进行了计算骨架曲线、恢复力模型与试验骨架曲线、滞回曲线的对比分析,结果吻合较好.计算结果表明,提出的恢复力模型可以良好的表达延性交错桁架钢框架结构双角钢组合截面弦杆的承载力和刚度退化等特征,可为结构的非线性动力分析提供参考.

To establish the restoring force model of double-angle built-up chords under cyclic bending in special staggered truss steel frame structure, six full-size double-angle built-up specimens were tested under cyclic bending, and the influence of the stitch spacing and stiffeners settings on the hysteretic behavior of the specimens were studied. Through analysis of test dates, the skeleton curve and rigidity degradation rule of the specimens were obtained and the restoring force models were determined as well. The three-liner skeleton curve of the restoring force was composed of the elastic stage, the reinforcement stage as well as bearing-degradation stage. Finally, the calculating skeleton curve and the restoring force model with the test skeleton curve and hysteretic curve were compared. The calculating model showed good agreement with the test curve. It showed that the calculating restoring force model can well express the bearing-capacity and rigidity degradation characteristics of the double- angle built-up chords in special staggered truss steel frame structure and can offer reference for the nonlinear dynamic analysis of the structure.