Technical constraints transformed into assets.
The structure is a metallic bridge with a through-arch supporting a curved suspended deck measuring 163 metres between abutment centres. The innovation in this bridge essentially lies in its complex geometry, resulting from a search for the perfect shape from a perspective of balancing thrusts.
Balance and curve
Due to the urban constraints on both banks, the route curves considerably as it passes over the Vauban docks. The placement of the arch, the width of the deck and the pattern of suspension cables offer sufficient gauge to allow the tramway and pavements to be created. They also result in a perfect balance of arch and deck thrusts.
BIM and 3D modelling
Egis designed the structure in three dimensions from the start of the design phase, using Inventor® software (published by Autodesk). This approach enabled a number of geometric options to be tested with great accuracy, and the optimum structure to be achieved.
At all stages of the design process, our teams sought to reconcile the requirements of the light rail system, in particular the rigidity of the deck, which supports the rails, with the flexibility of the suspended metal structure. The BIM (Building Information Modelling) approach helped control costs and meet deadlines.