Experimental study on PVC-CFRP confined reinforced concrete short column under axial compression

This paper presents the results of experimental investigations on 10 PVC-CFRP confined reinforced concrete columns.The influences of the hoop spacing of CFRP strips and the axial reinforcement on the load-carrying capacity,deformation and failure mode of PVC-CFRP confined reinforced concrete columns were studied.Test results show that the load-carrying capacity and ultimate compressive strain of axially reinforced members with reinforced ratio 1.8% respectively increase about 24% and 16% compared with those of members without axial reinforcement;the load-carrying capacity and ultimate compressive strain decrease with the increase of the hoop spacing of CFRP strips;when the axially reinforced members fail,multiple CFRP strips fracture and longitudinal reinforcement buckle at the middle height of the specimens.The stress-strain relationship curves of PVC-CFRP confined reinforced concrete column may be divided into three stages: at the first segment,the stress-strain relationship curves is parabola;at the second segment,the stress-strain relationship exhibits an obvious transition segment;at the third segment,before the failure of the axially reinforced members,the axial stress and strain is in the increasing state.The slope tangent of the hardening segment of axially reinforced members is larger than that of members without axial reinforcement.Based on the static equilibrium and limit equilibrium,a calculating formula of the bearing capacity of PVC-FRP confined concrete column was derived.The calculated values of the proposed formula agree well with the experimental results.