Study On Interface Shear Failure Forms And Rules Of CFRP Reinforced Concrete Composite Beam

Carbon fiber reinforced polymer (referred to as CFRP), due to its light weight、highstrength、corrosion resistance、fatigue resistance and other superior performance, overthe past ten years widely used in concrete structure engineering.This new type ofreinforced concrete structure is based on fracture mechanics crack resistance mechanism,through control thoughts of preventing cracks, apply the excellent mechanical propertiesof CFRP to the reinforcement of reinforced concrete structure. Scholars at home andabroad having made a lot of research about the composite structure.In this paper, by the static load testing of reinforced concrete composite beamswhich pasting one layer, two layers and three layers, Using strain and deformation indexand combining with the experimental phenomena to analyze the damage form of variouscomposite beam, the main contents and conclusions are as follows:①Analysis results of the ultimate bearing capacity and main parts of the strain anddeflection of composite beams show that, compared with the ordinary beam, mechanicalproperties of the composite beam has improved, with the increase of CFRP pastedthickness, this improvement became more evident, but this is not a linear relationship;②This paper mainly analyze the shear failure forms and rules of the compositebeam’s bonding interface. The interface stripping failure pattern of three kinds of beamare basically the same, which are beginning around the middle of the beam with twotypical bending shear fractures, and extend to the support end, the interface strippingfailure usually occurs in shallow concrete adjacent to concrete bonding interface. CFRPreinforced concrete composite beam’s adhesive interface shear stress process in theloading process has a basic trend, that is the beam’s deflection is small during the earlyperiod, the shear form of bonding interface is straight pull type, along with theincrease of deformation the straight pull type change to suspension type. This paperalso analyze the composite beam’s interface shear failure process, the relation betweenInterface fracture and the bearing capacity of the beam and the cracks extension rules;③In this paper, according to various failure pattern a calculation formula isdeduced, this formula could be used to calculate the number of CFRP when we pasteCFRP to strengthen reinforced concrete structure. The inferential process based on theflat section assumption and force balance therefore has a certain theoretical andpractical significance; ④The CFRP and GFRP composite beam’s test results were analyzed under thesame state and these conclusions may be benefit to practical engineering reinforcementwhen we confronted to the problem of choosing CFRP and GFRP;⑤At last, having pasted different layers of CFRP composite beam’s load failureprocess are simulated by ANSYS, and the comparison and analysis has been carried outfor the numerical analysis results and experimental results.