Experimental Study On Cfrp Anchored By Steel Pipe Strengthened Beam Negative Moment Area Of Frame Joint

Because the carbon fiber has excellent physical and mechanical properties, good adhesion, corrosion resistance, heat resistance, etc., having wide application in the field of civil engineering. Carbon Fiber Reinforced concrete structures technology with the construction process is simple and easy to operate, almost does not change the cross-sectional size and other characteristics of the original members, has been the concern of the civil engineering sector, many scholars at home and abroad in ultimate bearing capacity, ductility and other aspects of carbon fiber reinforced components had a lot of research on the field of theoretical and experimental and achieved fruitful results.At present, many domestic and foreign experts and scholars reinforcing beams are mainly concentrated in the positive moment, negative moment area of research is still limited, because CFRP anchorage at the end of the beam to be furtherstudy and discussion. On the basis of previous experimental study and theoretical analysis, produced seven specimens, the variables are the radius of the half steel pipe fixing the CFRP of beam negative moment area and the CFRP layer of beam negative moment area, used built-in expansion bolts outer anchoring half-pipe technology to reinforce beam negative moment area of six concrete frame joints, and a specimen was not any treatment, then did bending performance test, the Specimens were divided into two groups:the first group was classified based on the size of the half steel pipe radius, the second group was classified based on the number of layers of carbon fiber cloth.The failure characteristics, cracking load, the position of the first cracks, Ultimate bearing capacity and ultimate displacement were the primary phenomenon and data of this test. According to different radii half-pipe anchoring effect and the different CFRP layers reinforcing effect of the beam negative moment area discussed the results, and then on the experimental basis used ANSYS to calculate and analyze the test data.Test and analysis results showed that:(1) Used the implant expansion bolt outer anchoring half pipe technology to reinforce frame beam negative moment area of frame Joints, the ultimate bearing capacity and ductility of the specimen had been significantly improved.(2) Used the half steel pipe to anchor the CFRP of beam negative moment area, avoiding the CFRP at the beam-column joints subjected to stress concentration leading to destroy.(3) Used the half steel pipe to anchor the CFRP of beam negative moment area, the failure location was far away from maximum bending moment of the beam negative moment, to some extent, prevented the destruction of the core area of the frame joints.(4) Used structural plastic to fill bolt holes and made solid arc in the negative angle position of the node, not only substantially reduced the drilling damage to the frame joints, and increased the height of the beam section.(5) By the ANSYS simulation of the two sets of specimens and compared with the experimental data, further reflected the reliability of the test data and verified the feasibility of the proposed reinforcement method in engineering practice.