| This study focuses on the development of a fracture mechanics based-model that predicts the debonding behavior of FRP strengthened RC beams. In this study, the existing debonding models based on fracture mechanics are reviewed. The performances from a set of fracture mechanics-based bond strength models are compared with each other through a set of parametric studies. In order to make the comparison equitably, a diverse set of parameters used in collected models are carefully characterized as (1) parameters related to concrete, (2) parameters related to FRP, and (3) parameters related to adhesive and epoxy mortar. The corresponding reliability and accuracy is also confirmed by comparing with collected test data. A comparison of some of the major models in this class with experimental data shows that the accuracy in prediction of Pmax and Le varies substantially with very few of the models actually incorporating the effects of critical bond parameters such as adhesive thickness and characteristics of the FRP-concrete inter-phase.;Since no approach exists that can precisely predict the failure mode, an extensive database that contains different beam debonding failure modes is formulated. This database includes 351 concrete prisms bonded with FRP plates tested in single and double shear. The existing fracture-mechanics-based models are applied to this database. Unfortunately the properties of adhesive layer, especially a soft adhesive layer, used on the specimens in the existing studies were not always able to be found. Thus, the new proposed model was based on thirty-nine data, including fifteen newly conducted pullout tests and twenty four data selected from two existing studies that dealt with the application of a soft adhesive layers and the available adhesive properties. |
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