Custom Timber Formwork for the Feuerbach Tunnel

The Tunnel Feuerbach project between Stuttgart‘s main railway station and the Feuerbach station, which was commissioned at a cost of around 187 million euros, has been completed. The breakthrough of the 3 km long tunnel in June 2020 was followed by the complex and innovatively designed inner lining of the tunnels and the branching structure near Feuerbach station. Complex because the tunnels taper conically before reaching the station and the formwork had to be continuously adapted to the changing geometry. And innovative because the tunnel runs through large areas of anhydrite rock, which swells on contact with water and builds up enormous pressure. As a preventive measure, the tunnel lining and reinforcement were therefore strengthened accordingly. Previously, this tunnel through anhydrite was considered too much of a technical challenge; the massive formwork as well as reinforcement levels and the placement of concrete with a necessary thickness of up to 1.2 m were not considered feasible.