FRP-strengthened RC beams. I: Review of debonding strength models

Bonding of a fibre-reinforced polymer (FRP) plate to the tension face of a beam has become a popular flexural strengthening method in recent years. As a result, a large number of studies have been carried out in the last decade on the behaviour of these FRP-strengthened beams. Many of these studies reported premature failures by debonding of the FRP plate with or without the concrete cover attached. The most commonly reported debonding failure occurs at or near the plate end, by either separation of the concrete cover or interfacial debonding of the FRP plate from the RC beam. This and the companion paper are concerned with strength models for such plate end debonding failures. In this paper, a comprehensive review of existing plate debonding strength models is presented. Each model is summarised and classified into one of the three categories based on the approach taken, and its theoretical basis clarified. The review not only brings together for the first time all existing plate end debonding strength models into a unified framework for future reference, but also provides the necessary background information for them to be assessed in the companion paper using a large test database assembled by the authors from the published literature.