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In this study, a series of flexural tests were performed to evaluate the energy capacity and debonding strain of reinforced concrete beams strengthened with a carbon-fiber-reinforced polymer (CFRP). Seven reinforced concrete beams were fabricated and loaded up to failure in a three-point bending test. The type of CFRP laminate (plate or sheet), bonded length (1.44 or 2.16 m), and wrapping of the CFRP sheet were selected as the key test variables. The test results showed that beams strengthened with CFRP sheets were more effective than those strengthened with CFRP plates. The CFRP-strengthened beams showed an elastic energy greater than that of the control beam, but the opposite result was obtained for the plastic energy. The average debonding strains of the CFRP plates and sheets were 4,309 and 11,649 μ, respectively, which corresponded to 21.5% and 77.1% of their respective ultimate tensile. POLYM. COMPOS., 38:1418-1426, 2017. © 2015 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]

The flexural strength of reinforced concrete (RC) beams strengthened with a carbon-fiber-reinforced polymer plate, which fails by intermediate crack debonding, is evaluated. To consider the effect of debonding at the interface between the concrete and the CFRP plate, due to a flexural crack at the midspan, on the flexural strength of the beams, a strength reduction factor is proposed. This factor is derived from the results of flexural tests by using the model of effective strains and is defined as the ratio of the debonding strain to the ultimate strain of the CFRP plate. The validity, accuracy, and efficiency of the factor is verified by comparing analytical results with experimental data. The results of this study revealed that the strength reduction factor proposed can be used to efficiently assess the flexural strength of CFRP-strengthened RC beams with intermediate crack debonding. [ABSTRACT FROM AUTHOR]

Textile-reinforced mortar (TRM) is a strengthening material in which textiles are attached to reinforced concrete (RC) structures using an inorganic matrix. Although many studies on structural behavior, various factors that affect TRM behavior could not be determined clearly. Especially, the uncertainty in bonds due to inorganic materials was not considered. In this study, the flexural behavior of TRM-strengthened beams was determined considering intermediate crack debonding occurred. The TRM beam strengthening limit and TRM coefficients were defined considering the possibility of premature failure and experimental results of four other research on 22 specimens. Therefore, it is expected that a conservative design would be possible when the suggested strengthening limit coefficient is applied. [ABSTRACT FROM AUTHOR]