圆CFRP-钢复合管内填砼构件的受弯性能研究

对16根圆CFRP-钢复合管内填砼受弯构件以及4根圆钢管砼受弯构件开展静力试验并分析实验结果。对于未包裹纵向CFRP的试件，其荷载-跨中挠度曲线类似于对应的圆钢管砼构件的曲线；对于包裹纵向CFRP的构件，其荷载-跨中挠度曲线可以划分为以下几个阶段：弹性阶段、弹塑性阶段和下降段。圆CFRP-钢复合管内填砼受弯构件的延性要好于圆FRP筒内填混凝土受弯构件。对于具有相同钢管约束效应系数的试件。承载力提高率随着纵向CFRP层数的增大而增大。从加载之初直到最大承载力．钢管和CFRP筒在环向和纵向都可以协同工作。纵向受压最大点的环向扣应变最大，纵向受拉最大点的环向压应变最大，纵向受拉最大点的钢管对核心砼没有套箍作用。从加载之初直到大约0．8倍的极限承载力，试件纵向应变沿截面高度的分布基本符合平截面假定。纵向CFRP可以显著提高试件的刚度。

Bending Performance Study on Concrete Filled Circular CFRP-steel Composite Tubular Members

16 concrete filled circular CFRP-steel composite tubular flexural members and 4 concrete filled circular steel tubular flexural members are tested and the test results are analyzed here. Load-middle span deflection curves for members without longitudinal CFRP are similar to that of concrete filled circular steel tubular fluxural members and load-middle span deflection curves for members with longitudinal CFRP could be defined as following: elastic, elaso-plastic and softening stage. The ductility of concrete filled circular CFRP-steel composite tubular flexural members is better than that of concrete filled circular steel tubular flexural members. The load bearing capacity enhancement ratio increases as the longitudinal CFRP layer increase for members with the same steel tube confinement factor. Steel tube and CFRP tube could cooperate longitudinally and circumferentially from 0 load till the ultimate load bearing capacity. Circumferential tension strain at the biggest longitudinal compress strain point is the biggest and circumferential compress strain at the biggest longitudinal tension strain point is the biggest, steel tube around the point with the biggest longitudinal tension has no confinement on core concrete. From 0 load till about 0.8 times the ultimate load bearing capacity, the steel tube longitudinal strain distribution along the depth of cross-section obeys the plain section assumption. Longitudinal CFRP could enhance specimen's rigidity significantly.