Enhanced End Anchorage of Bonded FRP Repairs

Synopsis: When strengthening concrete structures using externally bonded composite material plates, the bond between the concrete and plate typically fails well before the plate’s tensile capacity is achieved. To enhance the bond performance, using composite fabric between the plate and the concrete was explored. Six tension development specimens were tested to determine the maximum tensile load that could be applied to a CFRP plate before it debonded. Three specimens had a Sika CarboDur strip bonded directly to the concrete, while three others had the CarboDur strip bonded to two plies of Sikawrap Hex 230C fabric material. The fabric was used to distribute the load over a larger bond area. The specimens without fabric failed at an average load of 60.5 kN while the specimens with the CFRP fabric failed at an average load of 92.6 kN. These failure loads represent 18 % and 27.5% of the plate capacity respectively.