Research On Seismic Performance Of CFRP-angle Steel Reinforced Seismic Damaged RC Frame

The RC frame structure will be destroyed under the action of strong earthquake,and most of the earthquake-damaged RC frame can still be used after reinforcement.Domestic and foreign scholars have carried out some researches on the reinforcement of earthquake-damaged frames,but most of them have studied the reinforcement of individual components or nodes.There are few studies on the seismic performance of the integrated seismic-damaged frame after reinforcement.The research on the reinforcement method and reinforcement implementation process of the seismic-damaged RC frame is in line with reality.Engineering requirements.CFRP cloth has the advantages of light weight,high strength,easy construction,corrosion resistance,etc.,but it cannot effectively improve the shear resistance of the joints;the angle steel can make up for the lack of shear resistance at the joints of the original component,but the separate externally bonded angle steel and unconstrained concrete produce The difference in material properties results in poor performance of collaborative work;combining the two can complement each other and give play to the respective advantages of the two materials.The addition of diagonal support to the component can effectively improve the stiffness and bearing capacity of the component,but the addition of the interface between the diagonal support and the component alone will cause poor coordination performance.In this paper,the composite reinforcement technology of CFRP cloth and angle steel is used in the reinforcement of earthquake damaged frames to obtain the seismic performance of the damaged frame after the earthquake,which has important guiding significance for promoting the application of CFRP and angle steel in seismic damage reinforcement.This paper takes the earthquake-damaged RC frame as the research object,and the main research work carried out is as follows:(1)The repair and reinforcement plan for the seismic damage specimens is determined,and a perfect repair plan is formulated according to the damaged location and damage degree of the damaged frame;according to the reinforcement principle,different design parameters and variables are considered,and the CFRP cloth and angle steel are determined Reinforcement design scheme.(2)Using high-strength non-shrinkage grouting material to repair the damaged specimens,ring-shaped reinforcement for the frame columns,U-shaped reinforcement for the frame beams,and X-shaped CFRP cloth for reinforcement of the frame nodes.Later,angle steel is used to strengthen the bottom of the column and the joints of the beam and column.Finally,the oblique support is used for reinforcement to form a CFRP-angle steel-oblique support reinforcement method.(3)The scheme of carrying out low-cycle repeated load test on the specimen.Based on the existing test conditions,combined with the loading method of the undamaged specimens,the repaired and reinforced specimens are subjected to a low-cycle repeated load test,and the whole process of the test is recorded.(4)Through comprehensive analysis of the failure process and failure mode of the RC frame after repair and reinforcement,and comprehensive analysis of the frame hysteresis curve,skeleton curve,displacement ductility,energy dissipation capacity,stiffness degradation,bearing capacity degradation and other performances,it is concluded that the repair and The seismic performance of the reinforced frame is compared with the seismic performance index of the initial specimen,and the improvement degree of the seismic performance of the specimen after repair and reinforcement is analyzed.Analyzing the working mechanism of CFRP and angle steel,the fitting formula of bearing capacity of CFRP cloth and angle steel is obtained.(5)Carry out numerical simulation analysis of different reinforcement methods.The seismic performance of the reinforced RC frame under low-cycle reciprocating loading is simulated,and the test results are compared to determine the feasibility of the finite element analysis and verify the accuracy of the model,and conduct a parametric analysis.