Sis Of Influencing Factors Of Seismic Performance Of RC Frame Joints Strengthened With The Beam-column-end--CFRP Indirectly

Abstract:Beam-column joints are important parts of reinforced concrete (RC)frame structures, it will lead to the collapse of the whole structure when the frame joints are destroyed. It’s difficult to apply the retrofitting-technology of concrete as a result of orthogonal beam and slab, and the debonding of the CFRP from the concrete is prone to occur because of the insufficient CFRP anchorage, the strengthening effect is not satisfactory. That is why the research about solving these problems is great significance. The method of internal joints strengthened with the beam-column-end-CFRP indirectly can improve the bearing capacity and seismic behavior, so it is more suitable for practical engineering framework nodes with orthogonal slab reinforcement. In this paper, the working mechanism and influence of different factors were discussed by numerical simulation of18RC frame internal joints strengthened with the beam-column-end-CFRP indirectly, and the design formula was also proposed, It’s also cpmpares the numerical simulation results and theoretical results.The main work and research are as follows:1) The load capacity, ductility and seismic behavior of18RC frame joints strengthened with the beam-column-end-CFRP indirectly were probed by numerical simulation. The consistency and effectiveness of the model is validated by the comparative analysis of hysteresis curve, skeleton curve, load capacity, ductility.2) This paper analyzes the influences of various factors on the load capacity and the seismic behavior of eighteen joints strengthened with the beam-column-end-CFRP indirectly. These factors include concrete strength, axial force ratio, shear span ratio, longitudinal bar reinforcement ratio of beam, stirrups reinforcement ratio of beam, hoop reinforcement ratio of joint core, the amount of longitudinal CFRP and the CFRP closed hoop at the end of the beam. And it also discusses the working of the joints.3)The results showed that improving concrete strengthshear span rati olongitudinal bar reinforcement ratio of beamthe amount of longitudinal CFRP can increase the load capacity of frame joints. Axial force ratio ma-inly influences seismic energy dissipation capacity. Increasing the stir-ups reinforcement ratio of beamhoop reinforcement ratio of joint corethe CFRP closed hoop at the end of the beam can significantly improve the d uctility of the joints.4) According to the relevant literature, the formulae for shear capacity of joints and beam, bending capacity of beam were derived. The formulae were verified by the finite element simulation results and relational experiment results. The formulae provides reference for design of frame joints strengthened with the beam-column-end-CFRP indirectly...