Experimental and numerical investigations of the effects of various tensile reinforcement types on the structural behavior of concrete bridge deck slabs

•The tensile reinforcement is in charge of the failure mode of the concrete deck slabs.•The post-cracking stiffness of hybrid-RC slabs was improved compared with that of FRP-RC slabs.•Hybrid-reinforced concrete slabs demonstrated better overall performance terms.•The FEM can predict the behavior of the hybrid-RC bridge deck slabs with good accuracy.•The FRP-to-steel reinforcement ratio is the key design tool for achieving gradual failure. Fiber-reinforced polymers (FRPs) have attracted attention owing to their ability to solve steel corrosion problems. However, FRP-reinforced concrete (RC) deck slabs were found to fail in a brittle shear manner due to the low stiffness of the FRP bars. In contrast, steel-RC deck slabs failed in ductile flexural failure by yielding of steel reinforcement. This study attempts to avoid such brittle failure in FRP-RC slabs by using hybrid steel/FRP bars that can provide serviceability, high strength, and durability. Seven full-scale reinforced concrete bridge deck slabs were cast and tested under four-point loading up to failure. The slabs were 3100mm length × 1000mm width × 200mm thickness. The investigated parameters were the reinforcement type and ratio and different patterns of the hybrid system. Subsequently, a finite element model was constructed, and the model results were compared to the experimental test results. Moreover, a numerical study was carried out by studying the different parameters affecting the shear behavior of RC members, such as the reinforcement ratio, FRP-to-steel ratio and wide range of the shear span-to-depth ratio. Based on the test results, Hybrid-RC slabs showed flexural-shear or compression-shear failure with ample warning than that reinforced with pure BFRP bars. Increasing the reinforcement ratio enhanced the overall slab performance at serviceability limit state. Furthermore, the numerical study indicated that the FRP-to-steel ratio should be Af/As ≤ 1.0 for achieving favorable ductile failure.