Approximate analysis of adhesive stresses in the adhesive layer of plated RC beams

A new popular method for retrofitting reinforced concrete beams is to bond fiber reinforced plastic (FRP) plates to the soffit. An important failure mode for such strengthened members is the debonding of the FRP plate from the member due to high interfacial stresses near the plate ends. As a result, previous researchers have developed several analytical methods to predict the interface performance of bonded repairs. In this paper, a theoretical interfacial stress analysis is presented, including creep and shrinkage effect for simply supported RC beams with a thin FRP composite plate. It explicitly considers the interface slip effect on the structural performance. The results agree reasonably well with those from the existing solutions. The influence of creep and shrinkage effect relative to the time of the casting and the time of the loading of the beams is taken into account. A parametric study has been conducted to investigate the sensitivity of interface behaviours to parameters such as the interface layer stiffness.