Behavior of concrete bridge deck slabs reinforced with fiber-reinforced polymer bars under concentrated loads

While the expansive corrosion of steel reinforcement is a major concern in reinforced concrete bridge deck slabs, the noncorrosive fiber-reinforced polymer (FRP) composite bars provide an excellent alternative reinforcement. In this paper, the behavior of edge-restrained concrete bridge deck slabs reinforced with glass FRP and carbon FRP bars was investigated Six full-scale deck slabs 3000 mm long x 2500 mm wide-x 200 mm deep were constructed and tested to failure in the laboratory. Three deck slabs were reinforced with glass FRP (GFRP) bars, two deck slabs were reinforced with carbon FRP (CFRP) bars, and the remaining slab was reinforced with steel bars as control. The test parameters were the reinforcement type and ratio in the bottom transverse direction. The deck slabs were supported on two steel girders spaced at 2000 mm center-to-center and were subjected to a monotonic single concentrated load over a contact area of 600 x 250 mm to simulate the footprint of sustained truck wheel load (87.5 kN CL-625 truck) acting on the center of each slab. The experimental results were presented in terms of cracking, deflection, strains in concrete and reinforcement, ultimate capacity, and mode of failure. It was observed that the mode of failure for all deck slabs was punching shear with carrying capacities of more than three times the design factored load specified by the Canadian Highway Bridge Design Code. It was also concluded that the maximum measured crack widths and deflections at service load level were below the allowable code limits. In addition, a new empirical model to predict the punching shear capacity of restrained FRP-reinforced bridge deck slabs was introduced and verified against the available models and experimental results of others researchers. The proposed model showed good agreement with the available test results.