Seismic Behavior Analysis Of Concrete Multi-story Frame Structure Strengthened With FRP

Because the frame structure is out of repair,improper use,unreasonable design,failure to consider seismic fortification or failure to meet the requirements,and earthquake,and so on,the need to strengthen the structurce,Compared with the traditional reinforcement method,the application of carbon fiber material has many obvious advantages.The technique of carbon fiber reinforcement is to use structural adhesive(epoxy resin)to attach carbon fiber materials with high elastic modulus and high tensile strength along or perpendicular to the axial direction on the tensile surface of the member in need of reinforcement.Shear and crack resistance can effectively improve the ductility and seismic performance of the members,thus the purpose of reinforcing and strengthening concrete structures is achieved.According to the requirements of the latest seismic design code of our country,this paper designs the frame structure of an eight-story composite office building based on the change of its use function.Through the finite element software SAP2000,the static elastic-plastic pushover analysis is carried out under the action of frequent and rare earthquakes,and the seismic behavior of the structure before and after strengthening is compared.The main contents and conclusions are as follows:(1)By referring to the current research situation of carbon fiber reinforced mulcti-story frame structure at home and abroad,grasp the theoretical knowledge of carbon fiber reinforcement,and extract the main research direction of this paper.(7)Determine the structure diagram,,define and set up plastic hinge,establish finite element three-dimensional model,modal analysis of the structure,it can be seen that the overall stiffness of the strengthened structure has been improved,and the deformation capacity has been enhanced.(3)The elastoplastic static analysis of the frame structure shows that the carbon fiber reinforcement method has no great influence on the initial stiffness of the structure,and the ductility of the reinforced concrete structure has been improved to a certain extent.The number of plastic hinges of the whole structure has also been reduced obviously,and the floor displacement have shown a decreasing trend.(4)By comparing the CFRP reinforced structure with the unstrengthened structure,the seismic performance of the strengthened structure is obviously improved,and the advantages of the strengthened structure in the aspects of economy and convenient construction are also highlighted.