Tunnel driving

Düsseldorf’s Wehrhahn-Line sets new standards
in subway construction

Fig. 1 Manufacture of the tunnel lining segments is in full swing at the new, high-capacity production line.

Fig. 2 The dimensional accuracy of each tunnel lining segment is checked by external test engineers. Tolerances in the tenth-of-a-millimeter range need to be adhered.

Fig. 3 During a visit to the manufacturer’s plant, representatives of both the city of Düsseldorf and the building contractor, Bilfinger + Berger, could satisfy themselves of the high quality of the precast elements.

Düsseldorf, the capital city of Germany’s federal state of North Rhine-Westphalia, is currently in the process of giving fresh impetus to its urban infrastructure. The 3.4 km long Wehrhahn-Line, which is scheduled to be finished in 2014 complete with six new subway stations, is the main traffic artery of the metropolitan railway construction. Combining state-of-the-art technology with architectural and artistic concepts, it will set impressive standards and count among the most modern and user-friendly subway lines throughout Europe. The line is expected to carry over 50,000 passengers per day, and will replace as many as five tramway lines. The overall investment will amount to € 650 million.

The new line passes under Düsseldorf’s city center – a highly sensitive area for residents, businesses and traffic management alike. For precisely that reason, most sections are built in trenchless construction, that is, by means of shield tunneling. State-of-the-art technologies and high-quality, highly innovative concrete elements only are used in the project to ensure that all work on the route is progressing smoothly and efficiently.

Strengthening tunnels by means of waterproof, single-shell ring elements of reinforced concrete, the so-called tubbings or tunnel lining segments, has...