This paper investigates a parametric study method to evaluate the partial and total mode components for energy release rate (ERR) in strengthened reinforced concrete beams (SRCBs) by fiber reinforced polymer (FRP) sheets. Externally bonding of FRP sheets is a general method of strengthening RC beams. Debonding along the FRP and concrete interface may produce a sudden failure of structures. A strong bonding between FRP and concrete is an important parameter on the behavior of RC beams. Previous experimental results and analytical methods have shown that debonding in the FRP and concrete interface is a complex phenomenon. The previous researches show that six types of failure due to debonding phenomena exist in reinforced concrete structures strengthened with FRP sheets. In this paper, one of the most important and common debonding type has been chosen. This one type of debonding is the separation between of the FRP sheet and concrete beam at the end of their connection. The present paper provides a parametric study method in realization of debonding phenomena and its effects on behavior of concrete structures strengthened by FRP sheets using mixed mode debonding analysis. Finally, the concordance of the finite element analysis (FEA) and existed results proves that the accuracy of the parametric study proposed approach to predict the debonding phenomenon is quite acceptable.
