Fatigue Behavior of Full-Scale Slab Bridge Strips with FRP Reinforcement

Abstract

Widespread deterioration of reinforced concrete (RC) bridge structures due to corrosion of steel reinforcement has resulted in an increased use of glass fiber-reinforced polymer (GFRP) reinforcing bars as an alternative reinforcement type for new bridge construction. Disadvantages of glass fiber-reinforced polymer reinforced concrete (GFRP-RC) flexural elements may include increased deflections and crack widths, significant reductions in the concrete contribution to shear resistance and susceptibility to fatigue failure. Posttensioned carbon fiber-reinforced polymer (CFRP) tendons can be used to effectively improve serviceability and shear resistance while increasing the fatigue life of the structure. An experimental study on the fatigue behavior of full-scale slab bridge strips with a reinforcement system combining passive GFRP reinforcing bars and active CFRP tendons is presented, along with analytical models to predict their fatigue lives and changes in stiffness resulting from repeated loading. The fatigue models presented are applicable to any GFRP-RC flexural members to predict changes in deflections, crack widths, and fatigue strength. The proposed reinforcement system presents a viable alternative to conventional design for short span slab bridges.