| Prefabricated structure refers to the concrete structure assembled by precast concrete members or components through a variety of reliable connections,including assembled monolithic concrete structure,fully assembled concrete structure and so on.The utility model has the advantages of high level of industrialization,convenient construction in winter,reducing the amount of wet work at the construction site,reducing material consumption,reducing site dust and construction waste and so on.For the widely used assembled monolithic concrete frame structure,the beam-column joint is an important part to ensure the effective force transmission and structural integrity,because there is a joint between the precast member and the post-poured concrete at the joint.the seismic damage of this kind of joints is different from that of cast-in-place concrete frame joints,so it is necessary to carry out special research on the seismic damage reinforcement of this kind of joints.At present,the main strengthening methods of joints are enlarged cross-section reinforcement method,bonded steel reinforcement method,wrapped steel reinforcement method,carbon fiber sheet reinforcement method.Among them,the CFRP strengthening method has the advantages of high material strength,light weight,simple process and so on.Many domestic scholars carry out experimental research and theoretical analysis on reinforced concrete structures based on different angles such as FRP material,joint form,damage degree and so on,but the reinforcement research for earthquake damage assembly monolithic structure is basically in a blank state.There is an urgent need to carry out relevant theoretical research.In this paper,the seismic behavior of integral reinforced concrete frame joints strengthened with carbon fiber sheets is studied by means of mutual verification of experiment and numerical simulation.In the test,four assembled monolithic joint specimens are made,one of which is used as a contrast specimen(without reinforcement without pre-damage),one is directly strengthened,and the other two are strengthened after pre-damage.The effects of seismic performance and pre-damage degree of beam-column joints before and after strengthening on the strengthening effect are studied through the repeated load quasi-static test on the column end of beam-column joints under load-displacement control,and the effects of axial compression ratio and carbon fiber sheet strengthening thickness on seismic performance are analyzed by using Abaqus finite element software.Finally,the strengthreduction coefficient of prefabricated damaged concrete is established on the basis of test and simulation,and with reference to the current concrete structure strengthening code and carbon fiber sheet technical specification,the theoretical formulas of beam flexural bearing capacity and shear bearing capacity of beam,column and core area are put forward. |
PDF Full Text Request