Stress-strain model of PVC-FRP confined concrete column subjected to axial compression

The design of PVC-FRP confined concrete members requires accurate evaluation of the performance enhancement due to the confinement provided by PVC-FRP tube. Based on the static equilibrium condition and the yield criteria of concrete and PVC-FRP tube, this paper presents a calculating model of the load-carrying capacity of PVC-FRP confined concrete column, the influences of the hoop spacing of FRP strips and equivalent confinement effect coefficient on load-carrying capacity were well considered. According to the ingression of experimental data, a calculating formula of the ultimate axial strain is also put forward. For this last case, a bilinear stress-strain model of PVC-FRP confined concrete column in axial and lateral directions is established. The comparison between experimental and numerical results indicates that the model provides satisfactory predictions of the stress-strain response of the columns.