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

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.