不同应变速率下CFRP约束混凝土方柱的力学性能

Mechanical behavior of CFRP confined concrete square column under different strain rates

为研究不同应变速率下碳纤维增强树脂复合材料(CFRP)约束混凝土方柱的力学性能,本文采用CFRP约束倒角半径为15 mm、45 mm、60 mm的方形试件,进行应变速率为3.3×10^(-5)s^(-1)、3.3×10^(-3)s^(-1)的加载试验,分析了试件倒角半径和应变速率对CFRP约束混凝土方柱的应力-应变曲线、轴向应变-环向应变曲线和抗压强度的影响。结果表明,试件的应力-应变曲线的第二段斜率和抗压强度均随着试件倒角半径与应变速率的增加而增大;轴向应变-环向应变曲线的斜率随着应变速率的增加而增大,随着CFRP的层数增大而减小。最后基于试验数据对现有文献的模型进行评估,结果表明Lin等模型的预测结果与准静态下FRP约束混凝土方柱的轴向应变-环向应变关系曲线比较吻合,魏洋等模型能够预测FRP强弱约束状态,Cao等模型可以用于预测不同应变率下CFRP约束混凝土方柱的抗压强度。研究成果为CFRP约束混凝土方柱的进一步应用提供了试验依据与理论基础。

In order to study the mechanical behavior of CFRP confined concrete square columns under different strain rates, CFRP confined square concrete square columns with corner radius of 15 mm, 45 mm and 60 mm were test with the strain rate of 3.3×10^(-5)s^(-1)and 3.3×10^(-3)s^(-1), respectively. The effect of corner radius of the specimen and strain rate on the stress-strain curve,axial strain-lateral strain curve and compressive strength of CFRP confined concrete square columns were analyzed. The results show that the slope of the second segment of the stress-strain curve and the compressive strength increase with the increase of the corner radius and strain rate. As the strain rate increases and the number of CFRP layers thickness decreases, the slope of the axial strain-lateral strain curve increases. Finally, the existing literature models were evaluated based on the experimental data. The evaluation results show that the prediction results of Lin et al are in good agreement with the axial strain-lateral strain relationship of FRP confined square concrete under quasi-static condition, Wei et al model can predict the harden and soften confinement of FRP, and Cao et al model can be used to predict the compressive strength of CFRP confined concrete square columns under different strain rates. The experimental results provide experimental and theoretical basis for the further application of CFRP confined concrete square columns.