ingenhoven associates

The heyday of railway stations in the 19th century saw great halls for train terminals in many European cities. Typically stations were erected outside the historic cities, which soon grew around them, turning the tracks into a hindrance to urban development. This is especially true for the city of Stuttgart in southwest Germany, which lies in a tight valley. The existing station is a terminus and difficult to link to the growing European high-speed rail network. A new high-speed line is being built in an underground tunnel at a right angle to the existing tracks. This will free up space for a new urban quarter. The project is called “Stuttgart 21” and envisages the new tracks up to 12 metres below the old, whereby the station building from 1922, which is listed as historic monument (architect Paul Bonatz and Friedrich Eugen Scholer), will be retained. The station will become the nucleus of the urban development and an interface between the old and the new city. It will give Stuttgart a much improved link to Europe and, even more, a new centre. The “Schlossgarten” (castle gardens) as the green heart and most important public green space in Stuttgart, will be extended above the new station.

The most striking impression of the new subterranean station, which ingenhoven architects have designed, will be its brightness and visual openness, which combines aesthetic with security advantages. The new station has a beautiful white concrete structure subjected only to compressive loads with minimal construction thickness. The thickness of the optimised shell structure was reduced to one hundredth of the span, resulting in the use of much less material. The reusability of the formwork and the prefabrication of modular components facilitate efficient construction. The development of a special concrete enables the visibility of the structure due to the exposed concrete surface without fire-rated cladding.

The station concourse will be illuminated by natural light through large circular “light eyes” during the day. The “light eyes” will establish the presence of the subterranean station in the minds of passers-by above. The 16 tracks with 17 platforms of the existing terminus are reduced to eight tracks with four platforms by increasing efficiency and reducing the travel times.

The intelligent use of natural energies and resources avoids CO2 emissions. The “zero-energy station” requires no supplied energy for heating, cooling or mechanical ventilation. This is achieved by benefiting from the warm ground water and warm air flow from the tunnels. Additionally, own-generation of energy is foreseen by PV-modules assembled on the roof of the station building.

The integration of the new station with its new public spaces and green areas into the urban grid creates a new quality for the city centre of Stuttgart. The unique nature-like structure of the station concourse creates a long-lasting aesthetic elegance of the loadbearing structure. The design of Stuttgart 21 translates the new era in rail transportation into a contemporary form.

Built
International competition 1997, 1st prize
Execution 2009 - 2021
GFA 185,000 m²

Cient
Deutsche Bahn AG, Berlin
represented by DB ProjektBau GmbH, Stuttgart

General Planning
ingenhoven architects, Düsseldorf

Architect
ingenhoven architects, Düsseldorf
Team: Christoph Ingenhoven, Klaus Frankenheim, Hinrich Schumacher, Dieter Henze, Stefan Höher, Annemone Ingenhoven-Feld, Christian Kawe, Peter Pistorius, Bjørn Polzin, Frank Reineke, Marc Böhnke, Barbara Bruder, Ralf Dorsch-Rüter, Peter Jan van Ouwerkerk, Alexander Prang, Michael Reiß, Takeshi Semba, Maximo Victoria, Tom Wendlinger, Harald Wennemar, Lutz Büsing

Scientific support
form-finding, design, construction and structure
Frei Otto, Leonberg

Structural Engineering
Ingenieurarbeitsgemeinschaft Tragwerksplanung S21 Hauptbahnhof GbR
Leonhardt, Andrä und Partner, Stuttgart
Happold Ingenieurbüro, Berlin
Werner Sobek, Stuttgart

Facade Consultant
DS-Plan, Stuttgart
Werner Sobek, Stuttgart

Building Services
DS-Plan, Stuttgart
HL-Technik AG Beratende Ingenieure, Frankfurt a.M.
Kofler Energies, Frankfurt a.M.

Building Physics
DS-Plan, Stuttgart

Fire Protection
BPK Brandschutz Planung Klingsch, Düsseldorf

Ventilation Analysis
IFI Institut für Industrieaerodynamik, Aachen

Lighting Artificial- and Daylight
Tropp Lighting Design, Weilheim

Landscape Architecture
ingenhoven architects
WKM Weber Klein Maas Landschaftsarchitekten, Meerbusch

Traffic Engineering
Ingenieursgruppe für Verkehrsplanung und Verfahrenstechnik, Aachen
Durth Roos Consulting, Darmstadt

Project Management
Drees & Sommer Infra Consult & Management, Stuttgart

Photos
H. G. Esch; Achim Birnbaum

Awards
2007 International Architecture Award
Holcim Awards Gold 2006 – Global
Holcim Awards Silver 2005 – Europe
MIPIM Architectural Review Future Project Awards 2005
BE Bentley Empowered Awards 2004 – nominated