The Research On Bearing Capaxity Of PVA-ECC Reinforced Concrete Square Column Subjected To Axual Load

Nowadays,in the rapidly developing structural strengthening,more old buildings and structures need maintaining,promted many new kinds of strengthening methods emerging . One of them is Polyvinyl Alcohol-Engineered Cementitious Composites (PVA-ECC) technology , a new method to reinforce the concrete structure.Depending on the fine properties of the materials and the fine cohension of the bondary agent,both the forrocement layer and the pre-component work harmoniously as a whole.This method is advanced technology , however, the research on axially loaded RC columns strengthened by this method under primary loading is rare. In order to put this method into practice, this article have taken several discusses on this method as a part series of studies about high tenacity fiber reinforced ferrocement concerte.Through on monotonic loading comparison experiment of six square columns, considered primary load strengthened columns seriously about the different steength of core concrete and the different spacing of reinforcing net bars,which have influence on the ultimate axial capaxity,peak strain,ductility,stiffness and crack resistance of strengthened columns. the formula of calculating its bearing capacity is set up by considering the effectively confined area and the ineffectively confined area in the column section and interface shear transfer.then compared the formula values with the experimental values;also analyzed the maximum and minimum reinforcement ratio of reinforcing net bars,which provide the basis for selection specifications of reinforcing net bars; Also according to the test results of regression analysis,the peak strain formula is concluded,then the ultimate strain formula is summed, so the two-phase constitutive model of reinforced concrete columns are given.Nonlinear finite element methods is employed to simulate the process of the loading test,which obain the specimen's bearing capacity,crack distribution,and the distribution of the reinforcement layer's stress and strain, then the test values are compared with the results of model, in order to testify the effectivity of strengthening method.Finally,the application of formulars is illustrated through a project example,for the sake of the spread of this technology applying in practice project.