Department Of Anchor Carbon Fiber Indirectly Reinforced Concrete Frame Nodes In The Mechanical Properties Of Experimental Research And Finite Element Analysis

Beam-column joints are very important element in reinforced concrete (RC) frame structures, destruction of the joints will lead to the collapse of the whole structure. Current researches on retrofitting technology of joints mainly focus on the plane frame joint cores strengthened with carbon fiber-reinforced polymer (CFRP) directly, which are not easily to be applied to practical projects. The method of internal joints strengthened with the beam-column-end-CFRP indirectly is more suitable for practical works and also can improve the bearing capacity of the joints with orthogonal slabs. Supported by Hunan Provincial Natural Science Foundation of China and Provincial Science and Technology Program, the force performance of four joints strengthened with the beam-column-end-CFRP indirectly was discussed by experimental study and numerical analysis. And the working mechanism and design formula of frame joints with lock-anchored CFRP sheets were also proposed. The main work and research results are as follows:1) The working mechanism, force performance and deformation behaviour of four RC frame joints strengthened with the beam-column-end-CFRP indirectly under a monotonic load were investigated by different anchorage methods. The methods include the through-slab CFRP closed hoops, the border-beam-slab U-CFRP anchored hoops and the bolt-plate lock-anchored CFRP hoops.2) The experiment results show that the bolt-plate lock-anchored CFRP hoop can effectively avoid the debonding of the longitudinal CFRP at the end of beam, significantly increase the ultimate capacity of the joint.3) The failure modes, load capacity and deformation behaviour of four RC frame joints strengthened with the beam-column-end-CFRP indirectly were investigated by numerical simulation. The numerical analysis results are shown to be in close agreement with the test data.4) The method of calculating the shear strength of frame joints strengthened with the lock-anchor 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 analysis results and experiment results. The formulae provide reference for the design of frame joints strengthened with the beam-column-end-CFRP indirectly.