基于变轴力和定轴力试验对比的钢筋混凝土柱恢复力滞回特性研究

在讨论了框架柱在地震作用下轴力变化规律的基础上,通过由变轴力柱和定轴力柱的低周交变加载试验获得的恢复力滞回曲线对比,给出了用各个“轴力变化半周”的“等效滞回轴力”修正恢复力骨架曲线,和用“等效累积滞回轴力”随时间步长调整累积强度退化系数从而修正恢复力滞回曲线的再加载刚度的建议。该建议能更有效、更方便地反映轴力变化的整个历程对变轴力柱恢复特征的影响,有利于提高钢筋混凝土杆系结构非弹性地震反应分析的有效性。

THE HYSTERETIC BEHAVIOR OF R/C COLUMNS BASED ON THE CONTRASTING TESTS UNDER CONSTANT AND VARYING AXIAL FORCES

The variation of axial force of the frame column under earthquake excitation is discussed first. Based on the comparison of hysteresis curves acquired by the column抯 cyclic loading test under constant and varying axial forces, the 揺quivalent hysteresis?gained at every 揾alf cycle of axial force?is used to modify the hysteresis envelope. In terms of the integral step, the 揺quivalent cumulating hysteretic axial force?is used to adjust the deteriorated coefficient of cumulating strength and hence to modify the reloading path. With the suggestions given by the authors, it is more efficient and convenient to reflect the influence of the whole history of axial forces on the hysterestic behavior of columns under varying axial forces. The results are also helpful to the improvement of the reliability of nonlinear dynamic response analysis of reinforced concrete (R/C) member-typed structures.