| Neither the CFRP (Carbon Fiber Reinforced Plastic) nor the steel plate strengthening concrete components shows sufficiency in improving structural force performance under low frequency cyclic load. The ductility of the member reinforced with CFRP will reduce. The failure of the member becomes all of a sudden and CFRP is not easy to anchor. Meanwhile, the member reinforced with steel plate can keep good ductility in loading and is easy to anchor, but the thickness of the steel plate and layer number are limited and the steel plate corrode easily. It can be improved the deficiency of the steel reinforcement by bonding CFRP, which is light, thin, durable and easy to paste. So the two materials have some complement in composite reinforcement. For some large important member, composite reinforcement is a kind of reasonable reinforcement form. It has theoretical significance and practical value to conduct the research.This paper reviews reinforced concrete beam using CFRP, steel plate, composite reinforcement and other different reinforcement methods at home and abroad. On this basis, force performance comparison tests are made with6concrete beams under low frequency cyclic load. Some contrast analysis are made including the failure characteristics,strain distribution, hysteresis curve, displacement ductility factor and skeleton curve, stiffness degradation and carrying capacity.The section ductility,cracking load,yield load and bending ultimate bearing capacity of the test reinforcement beam are analyzed, and the theoretical analysis results and the test results are compared.The Finite Element Method (FEM) is adopted. The finite element model of the composite reinforced concrete beam is established using APDL command flow in the FEM analysis software (ANSYS).Through the FEM analysis of six beams, the FEM analysis results and the test results are compared.At last, the paper has a discussion on CFRP appropriate content in composite materials in reinforcement beam.The test results, the theoretical analysis and the FEM analysis show that:(1) CFRP or steel plate reinforcement all can improve bearing capacity, deformation ability of the beam,effectively restrain the development of crack, reduce crack width, slow down the stiffness degradation.At the same time they have good deformation ability.Moreover, sticking CFRP is better than sticking steel plate on delaying crack development and restricting the crack width. Specimen reinforced with steel plate is better in its ductility and deformation ability and the stiffness degradation.(2) The composite reinforcement can more effectively improve the bearing capacity of the beam, slow down the stiffness degradation, and improve the force performance behavior of the reinforced concrete beam under low frequency cyclic load, meanwhile it has better ductility and deformation ability. Composite reinforced beam’s section ductility coefficient although lower than the section ductility coefficient of the reinforced beam bonded with steel plate, but the reducer range is not too much, it explains that composite reinforcement beam has a good section ductility.The test shows that CFRP and steel plate can work together very well.It basically conforms with flat section assumption.(3) The section ductility,cracking load,yield load and bending ultimate bearing capacity in theoretical calculation are in good agreement with the test results.(4) APDL command flow may simulate beam test process well. The bearing capacity using FEM analysis is in good agreement with the test results. Hysteresis curve using FEM analysis has a bigger difference with the test result, but they have the same change trend.(5) When CFRP content in composite material is appropriate, it can both improve the bearing capacity of the reinforced beam and have good deformation ability. By discussing the maximum, minimum and appropriate content value of CFRP content in composite material are discussed, the results can be a reference for practical engineering. |
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