CFRP环向约束方钢管混凝土压弯构件滞回性能

目的研究CFRP增强方钢管混凝土压弯构件在往复荷载作用下的力学性能．方法以4个CFRP环向约束方钢管混凝土压弯构件的滞回性能试验为基础，对其跨中荷载-挠度（P-△）曲线、跨中弯矩-曲率（M-φ）曲线、跨中挠度-轴向变形（△-d）曲线、应变以及挠度曲线形状进行分析．结果所有试件的挠度曲线均近似为正弦半波曲线；钢管和CFRP管可以协同工作；同一点的纵向应变和环向应变异号．结论CFRP对方钢管混凝土有很好的环向约束作用，钢管的局部屈曲得到了延缓．所有试件的跨中荷载-挠度滞回曲线均较为饱满，基本没有捏缩现象，表现出很好的滞回性能．所有试件的弯矩-曲率滞回曲线均较为饱满，在加载初期，试件的变形为弹性变形，进入位移控制后，产生不太明显的“包兴格”效应．

The Hystetic Performance of the Concrete Filled Square Steel Tubular Column-Beam Strengthened By CFRP Circumferentially

4 specimens were experimentally investigated in this paper to study the mechanical behaviours of the concrete filled square steel tubular column-beam strengthened by CFRP circumferentiaUy under cyclic load. Also,the mid-span load versus deflection （P-△） curves, mid-span moment versus curvature （M-φ） curves,mid-span deflection versus axial deformation （△-d） curves, strain and deflection curves shane were analyzed. The test results indicated that the deflection curves of all the members were approximately half sin wave;the steel tube and its outer CFRP material could cooperate;and also,the longitudinal strain and the circumferential strain of one same point had opposite sign. Analysis of the test results indicates that CFRP can provide circumferential confinement effect for the concrete filled square steel tube effectively and the local bulking of the steel tube is delayed. Mid-span load-deflection hysteretic curves of all the specimens are good and display perfect hysteretic behaviours. Mid-span moment-curvature hysteretic curves of all the specimens are good. Deflection of the specimen is elastic during the initial loading period, while it shows somewhat Bauschinger effect during the later loading period.