The lozenge roof of the new Vienna Central railway station was the worthy winner of the Austrian Steel Construction Prize. The roof structure, about six times the size of a football pitch, can be seen for miles around. It is one of the most complicated and beautiful steel construction projects in Austria and incorporates approximately 7,000 tonnes of steel.
The new railway station has provided Vienna with a central hub in the trans-Europe rail network, which will be used by more than 1,000 trains and by 145,000 people every day. The station’s spectacular steel and glass lozenge roof, 200 metres long and 120 meters wide, has become a symbol of modern mobility and functionality, and distinguishes the building from everything around it. The roof structure, which is made up of 14 individual diamond shapes, arches over five platforms. Its height varies between six and fifteen metres, so that it seems to hover over the platforms. Each individual rhombus consists of rods and nodes. The entire roof (including the forecourt canopy) is made up of more than 57,000 sections, 286,000 sheets of metal, and almost 340,000 screw fittings which are concealed beneath the cladding. The creation of the gigantic structure was a demanding challenge for the contractors and the steel construction company Unger Steel, not only from the technological point of view, but also with regard to the logistics of the project.
Corrosion protection using hot dip galvanizing
The complexity of the roof structure meant that it would be virtually impossible to maintain so the design allowed for individual members to be galvanized and bolted together to form the complex rhombus for each subsection of the roof. It was therefore possible to avoid costly maintenance work which would entail closures along with health and safety issues.
The 14 diamond trusses of the station canopy each measure 76 metres, and are all supported by solid twin supports every 38 metres. In the centre of the lozenge, the structure opens up to provide a skylight in the form of a crystal shaped opening measuring 6 x 30 metres. Integrated glass elements make it translucent and helps to flood the building’s interior with daylight. At night, special lighting gives the roof a gorgeous 3D effect. For the architect, the central station is more than an important traffic hub: “It’s a turntable in a Vienna which is open to Europe. The lozenge roof makes an important contribution to this as, with its dynamic design, its rhythm and the way it seems to float in the air, it acts as a structural synonym for Vienna, the world-renowned city of music.”
Architect: Albert Wimmer ZT-GmbH
Image: Renee del Missier, Unger Steel Groupt