Bond Characteristics of Various Frp Strengthening Techniques

Strengthening of reinforced concrete structures using FRP has emerged as a potential solution to the problems associated with civil infrastructure. Many researchers have reported significant increases in strength and stiffness of concrete structures strengthened with FRP. Nevertheless, possible brittle failures of the strengthened system due to delamination of the FRP strips and/or sheets could limit the use of the full efficiency of the FRP system. This paper presents a bond failure hypothesis for near surface mounted FRP bars. Closed-form analytical solutions are proposed to predict the interfacial stresses for near surface mounted FRP strips and externally bonded FRP sheets. The models are calibrated by comparing the predicted behavior to test results. Quantitative criteria governing interfacial debonding failure of near surface mounted FRP bars, strips and externally bonded FRP sheets are established.