考虑损伤的纤维增强混凝土剪力墙恢复力模型研究

通过理论分析与试验回归相结合的方法,对6个局部纤维增强混凝土(FRC)配筋剪力墙循环往复加载试验结果进行研究,提出了考虑轴压比、边缘约束区纵筋率、配箍特征值、FRC和钢筋力学性能以及钢套管等因素的骨架曲线特征点简化计算公式。同时,考虑加载历程对墙体性能退化的影响,通过引入一个基于试验拟合结果的损伤模型,定量描述了各试件滞回环卸载刚度和骨架曲线下降段强度退化规律,给出了恢复力模型滞回规则,并与试验墙进行了模拟对比,验证了模型的准确性。

Study on restoring force model of fiber reinforced concrete shear wall considering damage index

Using combined theoretical and experimental regression analysis methods, the results gained from quasi-static cyclic tests on six shear walls with fiber reinforced concrete (FRC) in bottom region were investigated. A set of simplified computational formula was presented to estimate the load-displacement skeleton curves of FRC shear walls, while considering influencing factors such as the axial load ratio, ratio of longitudinal reinforcement in boundary regions, confinement index of stirrups, mechanical properties of FRC and steel reinforcement, and steel sleeve. To evaluate the effect of loading history on performance degradation of FRC shear walls, a damage model was introduced based on the fitted results of cyclic loading test data. Also, the overall seismic behaviors including unloading stiffness of hysteresis loops and residual strength on descending branch of skeleton curve were assessed quantitatively by a proposed restoring force model and hysteresis rules. It was found that the simulated hysteretic behaviors had good agreement with test results, and the feasibility of proposed restoring force model was verified.