Static behavior of RC deck slabs partially prestressed with hybrid fiber reinforced polymer tendons

The design of traditional FRP-RC deck slabs incurs a waste of FRP due to the minimum limit of reinforcement ratio recommended by the current design specifications. This paper investigates the static behaviors of full-scale RC deck slabs transversely reinforced and prestressed with basalt/carbon fiber reinforced polymer (FRP) hybrid tendons, which are capable of enhancing the utilization efficiency of FRP reinforcement. Two nonprestressed control deck slabs and five prestressed FRP-RC deck slabs were tested up to failure. The experimental variables included FRP-reduction factor, prestress level and partial prestressing index. The results indicate that the amount of bottom transverse reinforcement of FRP-RC deck slabs is reduced by 45% through introducing prestressing into FRP reinforcement. Those three variables have negligible effect on the failure mode of the prestressed FRP-RC deck slabs. The FRP-reduction factor primarily affects the ultimate load and cracking load, crack width, and strain in nonprestressing reinforcements and concrete. Prestressing level has significant effects on the cracking load, deflection, crack width and strain in nonprestressed reinforcements. By contrast, partial prestressing index has no effect on the static behaviors of the FRP-RC deck slabs. Furthermore, the residual crack width and deflection of FRP-RC deck slabs are controlled significantly by prestressing, which contributes to realizing a superior long-term behavior of the deck slabs.