The new Bleichinselbrücke across the Alt-Neckar is a four-lane integral road bridge with cycle and pedestrian paths. Due to its particular location in a flat meadow it was decided to design a composite construction with concrete deck and steel box girders acting as main girders. The concrete deck consists of precast slabs that are based on steel girders, and in-place concrete. It is thus possible to avoid temporary scaffolds and to minimise the impact on landscape and shipping traffic during the construction phases.
Roadbridge "Rotes Steigle" across Highway A8
The highway A8 is to be expanded by an additional lane between the Stuttgart interchange and the junction Leonberg/Ost. Due to its restricted structural clearance, the existing arch bridge “Rotes Steigle” was replaced by a distinctive new structure, which provides a crossing for a forest road over the highway. The load bearing structure of the integral composite bridge comprises a lower arched steel box girder with varying cross-section dimensions, steel struts that are angled outwards, and a reinforced concrete deck slab. The slender construction was designed as a two-hinged arch that rests on stainless steel rocker bearings at the arch-support. It presents a modern contrast to the previous bridge.
The article linked below (p. 94) highlights the different aspects and challenges during both projects.