Study On Mechanical Behavior Of PVC-FRP Conifned Reinforced Concrete Column Under Eccentric Compression

PVC-FRP confined reinforced concrete column is a new kind of compositemembers, which is winding FRP strips on the outside of PVC tube as certain hoopspacing, then putting the reinforcement cage and pouring concrete in the PVC-FRP tube.PVC-FRP confined reinforced concrete column have many advantages such as highbearing capacity, convenient construction, good ductility and durability. This paperpresents the mechanical behavior of PVC-FRP confined reinforced concrete columnunder eccentric compression, the main contents include:According to the experimental study of stress-strain relationship of PVC-FRPconfined reinforced concrete columns under eccentric compression, the influence law ofthe spacing of FRP strips and eccentricity on the stress-strain relationship are analyzed.The results show that the stress-strain relationship of the PVC-FRP confined reinforcedconcrete columns under eccentric compression may be divided into two stages. In thefirst stage, the stress-strain relationship curves are parabola, In the second stage, thestress-strain takes on the the strengthening stage, the stress and strain have a linearrelationship.Based on the experimental study, considering the effect of hoop spacing of FRPstrips and eccentricity on the stress-strain relationship, the calculating formula ofequivalent confining coefficient of PVC-FRP tube to core concrete is put forward, andthen the stress-strain model of PVC-FRP confined reinforced concrete columns undereccentric compression is established. Based on the established model, a analyticalprogram is encoded to calculate the bearing capacity of PVC-FRP confined reinforcedconcrete column under eccentric compression by using the numerical integrationmethod. The predictions of the program agree well with experimental results. Based onthe deformation compatibility condition, the formula of confining force of PVC-FRPtube to core concrete is put forward, according to limit equilibrium condition, then theformula of the bearing capacity of PVC-FRP confined reinforced concrete column undereccentric compression is deduced. The predictions of the formula agree well withexperimental results.A nonlinear program is developed to predict this complete moment-curvaturerelationship and the load-deflection relationship of PVC-FRP confined reinforced concrete columns under eccentric compression by using fiber model method, then thecomputer program is verified. The influence law of the hoop spacing of FRP strips,eccentricity, the width of FRP strips, concrete strength and reinforcement ratio on themechanical properties of PVC-FRP confined reinforced concrete columns undereccentric compression are analyzed.Based on finite element software ABAQUS, the reasonable constitutive relationsof materials are chosen. The finite element analysis model of PVC-FRP confinedreinforced concrete column is established, then the analysis model is verified. Themechanical behavior of PVC-FRP confined reinforced concrete columns are analyzedby using the model, and the working mechanism of CFRP strips, PVC tube and concreteare revealed.