采用CFRP增强的GFRP管混凝土短柱轴压性能试验研究

Experimental study on axial compression behavior of concrete-filled GFRP tube short columns strengthened with CFRP

通过碳纤维增强复合材料(CFRP)布对玻璃纤维增强复合材料(GFRP)管约束混凝土短柱进行不同方式的加强,制作了12个两两相同的GFRP管约束混凝土短柱试件,研究不同增强模式下GFRP管约束混凝土短柱在单调轴压及重复轴压下的力学性能。分析了试件的破坏模式、承载能力、变形能力、增强效果、应力应变曲线、塑性残余应变与卸载应变的关系以及极限状态。结果表明:3种增强模式下试件的极限承载力均有很大提升;单轴受压试件的应力应变曲线与其在反复受压时的应力应变包络线基本一致;试件加强前后的塑性残余应变和卸载应变均存在线性关系,且在同种增强模式下,随着约束作用的加强,直线的斜率也随之增大。对Lam等提出的FRP约束混凝土加卸载模型进行修正,并对不同增强模式下GFRP管约束混凝土短柱在重复轴压下的卸载路径进行预测,通过与试验结果对比发现,修正后模型与试验结果吻合较好。

In order to study the mechanical properties of concrete-filled glass fiber reinforced polymer(GFRP)tubular short columns under single axial compression and repeated axial compression under different reinforcement modes,twelve two-identical specimens of concrete-filled GFRP tubular short columns were produced.And the concrete-filled GFRP tubular short columns were reinforced by carbon fiber reinforced polymer(CFRP)cloth in different ways.Based on the test results,the failure mode,load carrying capacity of columns,deformation capacity,reinforcement effect,stress-strain curve,relationship between plastic residual strain and unloading strain and limit state of specimens were analyzed.It shows that the ultimate strength of the specimens in three reinforcement modes is improved greatly;there is a linear relationship between the plastic residual strain and the unloading strain of the specimen before and after reinforcement,and the slope of the straight line increases with the strengthening of the restraint.Modifying the FRP-confined concrete loading and unloading model proposed by Lam et al.Predicting the unloading path of CFRP-reinforced GFRP pipe concrete composite short columns by the modified model under repeated axial compression in different reinforcement modes.After comparing,it shows that the test results agree well with the modified model.