Experimental Study On Cracking RC Beams Reinforced With Near-Surface Mounted CFRP

Due to the aging of the buildings, earthquakes and other reasons, some existing buildings can not meet the need of people’s normal functional requirements. Thus, they are required to be strengthened and reinforced, which has become the main tendency for the future development of the construction industry. It has become the inevitable trend of the sustainable development of the construction industry as well as a good reflection of the energy-saving emission reduction, and has significant benefits both socially and economically. The carbon fiber strips (CFRP), with many advantages of its own, has been widely used in the reinforcement construction works. Superior to the externally bonded reinforcement method, near-surface mounted reinforcement method, as a new reinforcement technology. However, its domestic research still remains in the initial stage.Based on the structure loading tests of eleven reinforced concrete beams, this paper takes three test factors (the strength of concrete, the damage extent and the embedded mode of carbon fiber strips (CFRP)) into consideration and focuses its research on the ultimate bearing capacity of reinforced beams.Firstly, based on previous research, an elaborate design of the experimental methods is made.A detailed observation, description and record of the test procedures are made in order to achieve the corresponding experimental results.Secondly, based on the consideration of concrete strength, pre-splitting degree and the embedded mode of CFRP board under various conditions, the pre-splitting mechanism, strengthened beam deflection, strain, crack, and ultimate bearing capacity are analyzed. The quantitative study on the changed index of reinforced concrete beams before and after reinforcement can be referred to the practical engineering applications.Thirdly, ultimate bearing capacity of the existing concrete～layer debonding formula is adopted to check the experimental data, and theoretical calculations and the experimental results are compared. By introducing the correction factor X of the reinforced pre-cracking concrete beams, the formula is corrected and revised. As a result, the revised theoretical figure of the ultimate bearing capacity matches well with the experimental results, which may provide a good reference for actual engineering calculation.