ABSTRACT
The purpose of this chapter is to describe the logic that controls the dimensioning of each component of a bridge deck. Clearly, this dimensioning will depend to some degree on the code of practice to which the bridge is being designed. In particular, the minimum thickness of members will depend on the current regulations on the cover required to protect reinforcement from corrosion. For instance, in the 1960s, the top slabs of precast Tee beam bridges (Chapter 10) on which the author worked in France typically had a minimum thickness of 160 mm for a beam spacing of 1.87 m (Pont du Saut du Loup) or 170 mm for a spacing of 3.35 m (Viaduc de la Porte de Versailles). The greater cover requirements of the British code, together with heavier loading lead Benaim to use a minimum thickness of 200 mm for the top slabs of precast Tee beam and box section decks. Recent changes in the British code of practice have further increased the required cover, and have led to another incremental increase in thickness in the UK. In other countries, where the environmental conditions and the rules are different, other minimum thicknesses will apply. The minimum thicknesses quoted in this chapter correspond generally to a concrete cover of 35 mm for the components of bridge decks in contact with the weather, and 30 mm for protected surfaces, such as the inside faces of concrete boxes.
