| Recently, an advanced composite material named Fiber Reinforced Polymer (FRP)is becoming increasingly popular in the construction industry for strengthening purposes as an alternative to traditional strengthening material. Several attractive properties such as high tensile strength, light weight, corrosion resistance and simple construction make it widely used in strengthening field. Project and experimental study indicate that bearing capacity and rigidity of concrete structures and components can be increased effectually and mechanical property can be improved by strengthing with FRP.But strengthening effect is weakened by debonding failure. This type of brittle failure not only make reinforcement inactivation but also even course component damaged. Based on predecessor theory and experimental study foundation, the paper focuses on following items:1. According to the process of debonding failure of test beams, shape of plate end debonding failure and intermediate crack induced interfacial debonding failure of concrete beam strengthened by FRP are described and mechanics are studied.2. Utilizing elastic mechanics and material mechanics,differential equation of interfacial shear stress and normal stress are deduced and analytical expression are obtained.3. Based on the formula, different value of the main parameters are studied and manner of improving of stress concentration are discussed.4. Through analyzing stress of superficial concrete in plate end interface, further study on phenomenon of plant end debonding is made, calculation method of debonding bearing capacity is obtained. The analytical results show a agreement with the experimental result.5. Discuss the key item of calculation formula of debonding bearing capacity, obtain a simplified bearing capacity formula which can be applied in project for reference.
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