Use of fiber reinforced concrete in compression slabs of beam-and-slab decks for new bridge constructions

Abstract

In the last decade, Fiber Reinforced Concrete (FRC) has allowed engineers to enhance the performance of different structural concrete members. From previous experiences in building flat slabs, it has been found that FRC members are capable of withstanding loads with either none or very reduced amounts of reinforcement. It has been proven that FRC enhances the resistance capabilities of flat elements under common internal forces (bending moment, one-way shear, punching, etc.). Given the compressive behavior of top slabs in bridge decks, the amount of minimum reinforcement placed in it might be higher than required by structural analysis. Considering the use of FRC in top slabs, an increased durability and/or an important reduction of reinforcement quantities could be achieved. In this research the results of the structural behavior of a top slab for a beam-and-slab deck considering the use of FRC are presented. It has been accounted for specific bridge loads and geometry layouts not found in other structural elements, such as building slabs. The structural analysis is done by means of global numerical model of the bridge, which has led to a combined transversal flexure and compressions in the longitudinal direction of the slab. The results show that minimum reinforcement at ultimate load can be slightly reduced (ranging from 12 to 18%) while providing an enhanced cracking control, which would turn into a durability performance increase of the slab.