Derivation of experimental debonding outputs for FRP-strengthened concrete samples through a fracture energy-based closed-form approach

Numerous bond-slip models have been proposed in the literature to elaborate on the behaviour between concrete and FRP. However, in most of these bond-slip models, the interfacial debonding fracture energy of the bond is not explicit. Furthermore, theoretical derivations of the experimental response of test samples from bond-slip models have often been calibrated with regression constants. This paper provides comprehensive theoretical derivations from the first principle using a bond-slip model with interfacial fracture energy. Thus, the explicit nature of the interfacial fracture energy in the bond behaviour is demonstrated. Moreover, the theoretical derivations eliminate the use of unhinged and statically dependent empirical constants. Furthermore, the presentation of theoretical derivations is showcased, succeeded by a series of sensitivity analyses of bond-slip parameters, accompanied by a comprehensive discussion on the significance of these parameters. Therefore, the analytical derivations with interfacial fracture energy presented in the paper are universal and can be applied to most scenarios where the implicit properties of the bond-slip model are unknown. • This study integrates interfacial fracture energy in concrete-FRP bond behaviour. • Characteristics of bonded concrete-FRP samples derived from first principles. • A series of sensitivity analyses evaluates the impact of bond-slip parameters. • The derivations apply broadly to bond-slip failure in composites.