The light rail arch bridge “Stadtbahnbrücke” consists of a central main span and two approach spans at 24m. The main span is connected by an 80m network arch and two protruding truss frames, which continue the swing of the slender arches–not only as sloped concrete supports but also as a visual element that leads all the way to the ground. The span between the footings is 107m. The free-standing arches are made from tapered steel box girders. A prestressed concrete slab is suspended from the arches by means of two series of inclined carbon hanger cables. The bridge was built for the Stuttgarter Straßenbahnen AG and spans the busy A8 highway east of the Stuttgart-Degerloch (B27) junction. It is an important part of the extension of the U6 light rail line to the city’s trade fair grounds and the airport. The bridge does not require any supports to span the highway, which features six lanes as well as four merging lanes and is approximately 80 meters wide in this spot. The sloped, crossing suspension cables consisting of carbon tension elements provide a supporting structure that is efficient and visually appealing. As far as we know, it is the first commercial application of carbon cables used for a network arch bridge. The three most important design objectives were a minimal disruption of traffic, an appealing design of the exposed structure as well as a robust and long-lasting design of all components and details. The main section of the bridge was manufactured on a temporary supporting frame besides the motorway. Then, during a brief highway closure, it was pushed to its final destination. schlaich bergermann partner was in charge of the entire planning – from design to technical spots check in shop and on site.
