Durability of FRP-concrete bond in FRP-strengthened bridges: a study of four in-service bridges in Canada

In many fiber reinforced polymer (FRP)-strengthened structures, the bond between FRP and concrete is the critical link in the reinforcement. The FRP-concrete bond is known to be affected by surface preparation and general concrete quality, properties and characteristics of the adhesive, external anchorage, FRP stiffness, FRP prestressing, and loading conditions. As a follow-up to an earlier study aimed at assessing the durability of glass FRP (GFRP) rods in concrete, a study was carried out to investigate the durability of externally bonded FRP in 4 in-service bridges. Research groups from several Canadian universities were involved. This article synthesizes the findings of this study.