Building in the city

Precast elements for urban infrastructure

Fotos: Amt für Verkehrsmanagement der Stadt Düsseldorf, DW-Werk Nievenheim, Berding Beton GmbH, Bekaert, Herrenknecht AG

Fig. 1 The tunnel christening ceremony of Construction Lot 2 of the new Wehrhahn Line was attended not only by those directly involved in the construction, but also by many citizens of Düssseldorf who dared to look down into the depth.

Fotos: Amt für Verkehrsmanagement der Stadt Düsseldorf, DW-Werk Nievenheim, Berding Beton GmbH, Bekaert, Herrenknecht AG

Fig. 2 A look into the year 2014: the “Kö-Bogen” in the hart of the new Downtown Düsseldorf in close proximity to the historic Hofgarten park.

Fig. 3 A new water supply and sewer network with DW high-performance reinforced-concrete pipes with nominal width of up to 2200mm was created long before the construction site for the Libeskind project directly next to the construction work on the underground station was cleared.

Fig. 4 and 5 A widely branching sewer network had to be newly constructed and/or rerouted, in many cases along the building fronts. The pictures give an impression of the “underworld” with deep manholes and partly pronouncedly curved pipe routings, all of which made of high-quality reinforced-concrete system elements.

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Fig. 6 Below ground less conspicuous, but here almost part of a sculpture park: egg-shaped profiles as high as a man were used mainly for the 4-km long sewer network.

Fig. 7 Construction principle of the new stations by means of shield driving and the cut-and-cover method. The greater part of the construction work takes place largely out of sight.

Fig. 8 Virtually non-stop segmental ring production in plant of DW Nievenheim.

Fig. 9 Three-dimensional calibration of the segments to check adherence to the extremely tight tolerance specifications of max. ± 0.3 mm.

Fig. 10 A masterpiece of tunneling technology: The driving machine, weighing over 1300 tons and 65m long in the factory hall of Herrenknecht awaiting transport to the construction site.

Fig. 11 Precision height: assembly of the eight precast segments to a ring weighing 46.2 tons.

Fig. 12 A tunnel tube certainly worth looking at.

Fig. 13 Removal of the temporary steelfiber segments in the first of a total of four stations that provide an impression of the dimensions of these structures built by the cut-and-cover method.

 A masterpiece of urban planning and logistics: Düsseldorf, the capital of the German state of North Rhine-Westphalia, is currently shouldering two construction projects at the same time that are truly extraordinary in terms of their dimensions alone. In addition, they are in close proximity to each other, directly in the heart of a city with very high traffic levels. The projects are the Wehrhahn underground line and the “Kö-Bogen.” These 100-year structures present a very special challenge to clients, planners, and contractors as well as to concrete technologist and precasters. Because projects of this magnitude are always one-of-a-kind, both with regard to design and to engineering, new know-how was required and – in many areas – implemented.

At the tunnel opening ceremony of the second construction section of the Wehrhahn line on 7 April, Dirk Elbers, the mayor of the city, described the Kö-Bogen and the underground line of 3.4-km length as outstanding works of civil engineering: “They attest to the future and enduring attractiveness of our city as well as promise greater mobility in the inner city for the people who live there.” The Wehrhahn line, especially with its artistic, individually designed stations, together with the Kö-Bogen, make the Rhine metropolis even more beautiful.