Limiting the crack width in reinforced concrete structures is essential to ensure a durable structure as it prevents accelerated corrosion of the reinforcement. For composite bridges, Eurocode HRN EN 1994-2 defines a very strict condition of a maximum crack width of 0.15-0.2 mm, which must be met for frequent combinations of actions. Since cracks in the deck slab of continuous girder composite bridges are to be expected and are unavoidable in the areas of middle supports, a considerable amount of reinforcement must be installed in a very limited deck slab thickness of only 25 to 30 cm. Depending on the local load bearing plate direction, the deck plate can be subjected to both, a very large longitudinal bending moment derived from the local behaviour, and an axial tensile force derived from the composite action of the main girder. The summation of these internal actions in the areas where the most unfavourable superposition occurs leads to a complex calculation and design procedure, that results in a very large reinforcement area. Omnia panels are often used instead of conventional formwork to enable a faster and more efficient erection process. In this case, additional reinforcement must be placed in the limited in-situ part of the slab thickness to allow a continuous action between the precast elements of the omnia slabs. This paper presents a numerical model investigation of such an example, used to determine the crack reinforcement in a continuous composite girder bridge with a deck slab erected using omnia panels, whose longitudinal load bearing direction coincides with the direction of the main girder span. The derived reinforcement must satisfy the ULD design and SLS crack verification, taking into account both the local behaviour of the deck slab and the global behaviour of the main girder simultaneously.

composite bridges; deck slab; reinforced concrete; crack design; Eurocode