Of Cfrp Indirectly Reinforced Concrete Frame Bearing Capacity Of The Node And Its Influencing Factors Finite Element Analysis

Beam-column joints are important elements in reinforced concrete (RC) frame structures, destruction of the frame joints will lead to the collapse of the whole structure. Current researches on retrofitting technology of joints mainly focus on the plane frame joints core strengthened with carbon fiber-reinforced polymer (CFRP) directly, but It is easily to be applied to practical projects by using longitudinal CFRP and CFRP closed hoop sticking in the end of beams and columns to strengthen the beam-column joints indirectly.The seismic behaviour of these joints can also be upgraded.In this paper, the working mechanism and influence parameters were discussed by numerical simulation of 12 RC frame internal joints strengthened with the beam-column-end-CFRP indirectly, and the design formula were also proposed.The main work and research results are as follows:1)The failure modes, load capacity and seismic behaviour of 12 RC frame joints strengthened with the beam-column-end-CFRP indirectly were investigated by numerical simulation. The feasibility and effectiveness of the model is validated by the experiment results of relational literature.2) The influnces of various parameters on the capacity and seismic behaviour of joints strengthened with the beam-column-end-CFRP indirectly were analyzed These parameters include concrete strength, axial force ratio, longitudinal bar reinforcement ratio of beam, hoop reinforcement ratio of joint core, shear span ratio, the amount of longitudinal CFRP and the CFRP closed hoop at the end of the beam.3)Based on the numerical simulation results, the working mechanism of frame joints strengthened with the beam-column-end-CFRP indirectly was analyszed.4) According to the strength calculation model of the FRP confined concrete, the method of calculating the shear strength of frame joints strengthened with the beam-column-end-CFRP indirectly was suggested, and the formulae for bending and shear capacity of beam were also derived. The formulae were verified by the finite element simulation results and relational experiment results.The formulae provides reference for the design of frame joints strengthened with the beam-column-end-CFRP indirectly.