The 64-metre-long and 53-metre-wide wildlife bridge with greenery is being built in the northern Black Forest between the forest area of Hagenschieß and Niefern-Öschelbronn at the entrance to the Enz Valley on an important wildlife corridor of international significance. Coming from the direction of Stuttgart, it marks the beginning of the 4.8-kilometre-long Enz Valley Crossing construction project. In this major project, the motorways agency Autobahn GmbH Niederlassung Südwest is widening one of the last four-lane sections of the A8 in Baden-Württemberg to six lanes between the Pforzheim-Süd and Pforzheim-Nord junctions. The green bridge built over the A8 as part of this project allows endangered species of wild animals to migrate freely within their natural habitats. In addition, the green bridge will provide a safe habitat for numerous regional animal and plant species.

Closing the gap on schedule

The integral arch bridge, consisting of six half-arch sections, was constructed using mobile scaffolding. Until the two half-arches were firmly connected, they were held in place by a supporting structure on the central reservation. For the ‘marriage’, 36 hydraulic presses lifted the concrete parts up to 3 centimetres from the supporting structure. The 1.5-metre-wide gap was then concreted.

The construction site is located on a carriageway and traffic is diverted to the opposite lane – a situation that required complex planning and construction site coordination as part of the major motorway project. Thanks to a committed team effort, the gap closure was completed on schedule.<s> </s>

Completion of the superstructure is pending

Before the wildlife crossing can finally be handed over to nature, some construction and landscaping work still needs to be done. The next step is to concrete the caps. The superstructure will be waterproofed, as well as provided with an approx. 10-centimetre-thick, reinforced protective concrete layer, before around 20,000 cubic metres of soil or substrate layers are applied for planting with species-appropriate flora. The 2-metre-high noise barriers on both sides are among the most important functional components of the wildlife crossing. They are highly absorbent, protect the wild animals crossing the road from disturbing noise and light, and thus guide them safely across the crossing aid.

Overview of the six-lane expansion of the A8 near Pforzheim:

www.autobahn.de/planen-bauen/projekt/a8-enztalquerung