Carbon Fiber Reinforced Research And Analysis Of Reinforced Concrete Beam

The flexural behavior and strength of concrete beams reinforced by CFRP were investigated experimentally and analytically in this study. Fifteen simply supported beams include three normal reinforced concrete (RC) beams and twelve CFRP reinforced concrete beams which were tested to generate the initial cracks before they were strengthened. The main variable parameters of beams are the reinforcement ratio, the initial cracks and the CFRP amount.Specially, the following items were observed and measured in the experiment: the steel strain, CFRP strain and concrete strain, the deformed curves, the shape and propagation of cracks, ultimate load and failure mode; and the load-deflection curves were plotted. The normal RC beams and CFRP reinforced concrete beams were compared hi the term of load-displacement curves, the appearance, propagation, width and interval of the cracks and the steel strain.According to the results of the tests, the main achievements are as follows:First, there is no difference in the flexural resistance and failure mode between the CFRP strengthened RC beams with initial cracks and that without initial cracks.Second, the characteristic of crack and the mechanism of average crack spacing variation in CFRP reinforced RC beams are analyzed.Third, the conclusion is proposed that the maximum crack width generated in RC beams reinforced by CFRP is narrower than that hi normal RC beams under the same load. In this experiment, the value of crack width can reduce 25 percent when the maximum crack width is not bigger than 0.2mm.Fourth, the formula of the maximum crack width and average crack spacing of CFRP strengthened RC beams are given.Finally, in the paper, it is discussed that the effect of the reinforcement ratio , the initial crack and the amount of CFRP on the flexural capacity of RC beam reinforced by CFRP. Calculating model is established according to the experimental result and the failure mechanism. The available calculating formulas derived from plane assumption for calculating the ultimate flexural capacity of CFRP strengthened RC beam with flexure waspresented and compared to the results of experiment.