Shear Friction Capacity of Concrete with External Carbon FRP Strips

Carbon Fiber Reinforced Polymer (CFRP) composite strips were used to strengthen concrete externally at a known failure plane to resist shear friction. The uncracked push-off specimens were externally reinforced with CFRP composites using a reinforcement ratio ranging from 0.3 to 1.2%. The shear friction capacity of plain concrete without steel reinforcement was increased 1.32-3.25 times, and was found to be a function of the shear-to-normal stress ratio. The shear friction strength ranged from 0.17fʹc to 0.27fʹc for the reinforcement ratios studied. Tests with various wrapping schemes showed no evidence that additional shear friction capacity could be developed for a four-sided scheme compared to a two-sided scheme. The shear friction strength of the initially uncracked connections was found using experimental results, which combine the shear friction contribution of concrete and that of concrete-CFRP interaction, similar to current practice for internal steel reinforcement.