Debonding failure in FRP-strengthened RC beams: A model-based approach

Simplified formulae for intermediate debonding in RC beams externally strengthened by FRP usually provide the maximum axial strain developed in FRP at debonding onset. Such formulae often derive by numerical regression of experimental results on relationships involving few parameters which possibly control the occurrence of intermediate debonding phenomenon. Consequently, the effect of several parameters on the behaviour of strengthened beams which fail for intermediate debonding is kept hidden by the huge aleatoric uncertainty affecting experimental results. In the present paper, a theoretical model already presented by the authors will be mainly utilized for shedding light on the role played by some parameters usually neglected by the most popular and widely accepted formulations for intermediate debonding.