高强混凝土加芯柱恢复力特性研究

基于6根试验柱在既定轴力下的低周往复加栽试验数据、滞回曲线及各阶段的柱顶水平荷载和位移，以峰值荷载点为基准，将试件的骨架曲线拟合为三线段，确定了试件屈服点、极限点与峰值点的关系，根据荷载达峰值时的柱顶水平位移及截面平衡条件推导出了峰值荷载的计算公式；对试验结果进行分析，得到了极限位移、峰值荷载对应位移与核心区纵筋配筋率、核心区面积比及配箍特征值的线性公式；结合试件的滞回规律构建了高强混凝土加芯柱的恢复力模型，并将计算滞回曲线与试验值进行了对比。结果表明：拟合的骨架曲线特征点的计算方法具有较高的精度，构建的恢复力模型与高强混凝土加芯柱的试验滞回曲线吻合较好。

Research on the Restoring Force of High-strength Concrete Columns with Central Reinforcement

Based on the test results of 6 specimens under constant vertical load but low-cycle horizontal load,including the hysteretic curves,horizontal load values and corresponding displacements at the top of each specimen at each stage of loading,and with the peak load as reference point,their skeleton curves were fitted as idealized tri-linear curves so that the relations between the yield point,points of ultimate displacement and peak load were determined.On the basis of horizontal top displacements at peak load and internal force equilibrium of the cross section,the formula for the calculation of peak loads was derived.From the analysis of test results,a linear relation of ultimate displacement and displacement at peak load with core longitudinal reinforcement ratio,core area and property of tie was obtained.In combination with the hysteretic properties of the specimens,the restoring model of such type of columns was obtained.The research results indicate that this method for the calculation of the characteristic points of fitted tri-linear skeleton curves has high precision,and the constructed restoring force model of high-strength concrete columns with central reinforcement matches well with the hysteric curves from the test.