FRP约束混凝土短柱在重复轴压作用下的力学性能

Mechanical behaviour of FRP-confined concrete short columns under cyclic axial compressive load

为了研究纤维增强复合材料(FRP)约束混凝土短柱在重复轴压荷载作用下的力学性能,对其进行试验和理论研究.共对6个FRP约束混凝土短柱试件(含3个单调加载和3个重复加载试件)进行竖向轴压试验.基于试验结果,分析讨论试件的破坏模式、应力-应变曲线、塑性残余应变、应力退化和极限状态.试验结果表明,重复荷载作用下试件的包络曲线略低于对应的单调荷载作用下试件的应力-应变曲线;卸载应变和塑性残余应变存在线性关系;FRP约束混凝土在重复荷载作用下的应力退化系数基本保持不变.根据国内外学者提出的理论模型,对重复加载试件的卸载路径曲线、再加载路径曲线和全过程应力-应变曲线进行预测.通过与试验结果比较,证明这些模型具有准确性和合理性.

In order to investigate the mechanical behaviour of a short column confined by fiber reinforced polymer (FRP) under cyclical axial compressive load, experiment on it and theoretic study were conducted. Axially compressive test was conducted on a total of 6 specimens of short column including three specimens under monotonic load and three under cyclic load. Based on experimental result, the failure modes, stress vs strain curves, plastic residual strain, and stress deterioration and ultimate conditions of the specimens were analyzed and discussed. It was shown by experiment result that the stress vs strain envelopping curve of the cyclically loaded sample would be slightly lower than that of monotonically loaded sample, unloading strain would be linearly proportional to plastic strain, and the stress deterioration coefficient of FRP confined concrete under cyclical compression would basically be unchanged. Theoretical models proposed by domestic and overseas scholars were adopted to predict the curves of unloading path and reloading path and the full-stage stress vs strain curves of the tested specimens. The accuracy and reasonability of these models were finally assessed by comparing to the experimental results.