Abstract
Recently, a rehabilitation of existing damaged steel members by bonding patch plates has been reported. The rehabilitation by bonding patch plates has essentially concern about the debonding from the steel members. To assist the verification of debonding prevention, the shear and normal stress in adhesive layer have been theoretically clarified. For debonding verification of patch plate, principal stress in adhesive has been adopted in some guidelines for strengthening of steel member with CFRP (Carbon Fiber Reinforced Polymer) plate. On the other hand, an energy release rate (ERR) for verification of debonding patch plates has also been employed in the guidelines. However, the ERR equation in the guidelines is not divided into debonding modes I and II, which are the opening debonding mode and the in-plane shear debonding. Depending on the loading conditions, the ERR of each mode might be required for verification of debonding prevention. In this study, the ERRs equations of modes I and II were derived from the shear and normal stresses in adhesive. Furthermore, Finite Element (FE) analysis was conducted to verify the ERR of each mode. As the result, the ERRs of mode I and II were close agreement with the FE results.
