Abstract: The combined effect of various contact interfaces of HB-FRP reinforced concrete leads to more complex interfacial bonding properties. Based on the experimental study, the HB-FRP numerical model was established which considering the plastic damage of concrete and interfacial bonding. The load-slip relationship, the interface strain distribution, the bond-slip relationship and the interfacial failure mode were compared and analyzed. The relationship between the number of FRP layers and the spacing of steel fasteners was analyzed. The results show that the numerical model can reliably reflect the bonding properties of HB-FRP reinforced interface, and HB-FRP reinforcement can effectively inhibit the development of debonding. The bond-slip relationship at the steel fastener is characterized by the typical trilinear shape of elastic rise, softening decrease, residual platform. The bond stress is finally stabilized rather than reduced to zero. Concrete failure surface at the steel fastener is "wedge-shaped" where the debonding thickness is greater than that of ordinary FRP bonding. Tensile strength increases after FRP thickness exceeds 5 layers. Tensile strength will not continuously increase as the spacing between steel fasteners decreases. When the spacing between steel fasteners is 250mm, the reinforcement efficiency of HB-FRP reinforcement mode can be fully utilized, which is 4.2 times that of ordinary FRP.

Key words: HB-FRP, concrete, reinforcement, bonding, numerical simulation