方钢管高强混凝土柱恢复力模型研究

Research on the restoring force model of high strength concrete-filled rectangular steel tubular columns

根据23根方钢管高强混凝土柱在反复水平荷载作用下的试验结果,通过理论分析和试验结果的回归分析,提出了方钢管高强混凝土柱的恢复力模型;确定了轴压比、约束效应系数、长细比等主要参数与恢复力模型之间的关系;给出了各特征点参数的计算方法。研究结果表明:最大荷载与屈服荷载的比值、退化刚度与弹性刚度的比值都随着轴压比和长细比的增加而减小,随着约束效应系数的增加而增大;按建议的恢复力模型计算的骨架曲线与试验曲线符合较好。文中建议的恢复力模型既反映了主要影响因素,又便于对结构进行非线性动力分析。

Based on experimental results of 23 high strength concrete-filled rectangular steel tubular （HCRST） columns subjected to cyclic lateral load, the restoring force model of HCRST columns is researched. Through theoretical and regression analysis and experimental results, the relations between the restoring model of HCRST columns and axial load ratio, confinement effect coefficient as well as slenderness ratio are discussed. The calculating meth- ods and steps are established. The results show that the ratios of degraded stiffness to elastic stiffness and maximum loads to yielding loads are proportional with confinable effect coefficient, and are inversely proportional with axial load ratio and slenderness ratio. Many various influential factors are considered in the restoring force model of HCRST columns. The model is close to the experimental results, which can be conveniently applied to nonlinear dynamic analysis of tall building composite structures.