The Effects of Concrete Cracks on Interfacial Properties of RC Beams Strengthened with FRP

摘要

During loading process, the arisen micro-cracks at the interface end of the strengthened concrete beam propagate with the load increases; it will eventually result in peeling failure of protection layer at interface end. The interfacial debonding stress between adhesive layer and concrete also increases, which may result in another interfacial failure, i.e., a very thin layer of fiber combined concrete was pulled down. Near the interface end, short vertical cracks in concrete were pre-established, and a numerical analysis model for interface end was established in the paper. The effect of crack sizes, crack locations and the number of cracks on interfacial mechanical properties was studied. Analysis shows that at the location of the cracks, the axial stress of fiber cloth appears a maximum value and is prone to local break.