Study On Seismic Damage State Of RC Circular Pier Strengthened With Prestressed CFRP

Due to the existence of the Pacific Rim and the Eurasian seismic belt,large and small earthquakes occur frequently in China for many years,so a large number of existing bridges in our country have suffered varying degrees of damage.Especially bridge pier,as the main component of the bridge to resist side force,there are some problems such as damage work and insufficient seismic capacity.Therefore,seismic reinforcement is very important.Traditional Carbon Fiber Reinforced Polymer(CFRP)strengthening RC(Reinforced oncrete)columns have the problem of stress lag and CFRP can not perform high strength material characteristics.By actively constraining core concrete,prestressed CFRP can give full play to the high strength of CFRP material,and improve the reinforcement effect.In order to quantify the seismic damage of RC pier columns,many damage models have been studied by scholars.There are few researches on prestressed CFRP reinforced pier columns with damage.Therefore,based on the pseudo-static test of six RC pier columns strengthened with prestressed CFRP,the construction of the seismic damage model is studied.To expand the analysis,the finite element software is used.Meanwhile,the calculation results of the limit damage under different damage and different reinforcement amount are verified.The main content is as follows:(1)The pseudo-static test scheme for strengthening damaged RC circular pier with prestressed CFRP is designed,and the prestress is applied to CFRP in the form of bolt anchors.Through the completion of pseudo-static test data acquisition and phenomenon description,draw the hysteretic curve and skeleton curve of each pier column.The reinforcement effect of different amount of prestressed CFRP on different initial damage pier column is analyzed from the aspects of maximum bearing capacity,maximum displacement,energy dissipation and ductility.(2)To quantify the damage of reinforced column,a damage model for RC circular pier reinforced with prestressed CFRP is established by analysing the pseudostatic test results and several typical damage models.By calculating the limit damage amount and damage evolution law of the pseudo-static test pier column,the validity of the proposed method are verified.(3)To verify the accuracy of the numerical simulation,the finite element analysis of the above quasi-static test was carried out by ABAQUS.In addition,the initial damage size and the amount of prestress reinforcement are changed,and the finite element model is simulated by pseudo-static test again to study the reinforcement effect of different prestresses under medium and low damage state.The last,the damage limit is calculated by using the damage model to verify the accuracy of the damage model.