which are inflated and deflated during the folding process. Circular ring beams At the time of its erection, the bent plan-view form of the Kelheim bridge across the Main-Danube Canal caused quite a stir: it was the first one-sided suspension bridge. Meanwhile, the engineers of schlaich bergermann partner have varied this principle of the circular ring beam many times, for projects such as the pedestrian bridge in Bochum; across the Gahlensche Street in Gelsenkirchen; the "Balcony to the Ocean" in Sassnitz; and the Liberty Bridge in Greenville, South Carolina, USA. For the ZOB Hamburg, this principle was applied to the roof structure. Cast steel The engineers were a part of the renaissance of cast steel for structural engineering. During the construction of the cable net roofs for the Olympic Games in Munich, this rediscovery made the construction feasible and allowed for the timely completion of the project. The cast steel allows for the production of geometrically complicated pipe nodes and an optimal alignment to the load distribution. Nowadays dynamically curved cast steel nodes are used for street bridges (Nesenbachtal Bridge, Stuttgart) and railroad bridges (Humboldthafen Bridge, Berlin) as well as for high rise buildings (Exhibition Hall 13, Hannover). Literature Holgate, Alan, The Art of Structural Engineering, Edition Axel Menges, Stuttgart (Germany), , 1997 Schlaich, Jörg; Matthias Schüller; Ingenieurkammer Baden-Württemberg, IngenieurbauFührer Baden-Württemberg, Bauwerk Verlag, 1999 Bögle, Annette; Schmal, Peter Cachola; Flagge, Ingeborg: leicht weit / Light Structures, Prestel Verlag, Munich (Germany), , 2004 Baus, Ursula; Schlaich, Mike: Fußgängerbrücken: Konstruktion Gestalt Geschichte, Birkhäuser Verlag, , 2007 Schlaich, Jörg; Bergermann, Rudolf; Schiel, Wolfgang; Weinrebe, Gerhard: The Solar Updraft Tower, Bauwerk Verlag Jaeger, Falk: 3 Stadia 2010: Architektur für einen afrikanischen Traum, Jovis Verlag, Berlin (Germany), , 2010 Schlaich, Jörg, Gut genietet ist besser als schlecht geschweißt. Sozialer Brückenbau - die Second Hooghly Bridge in Calcutta, in: Deutsche BauZeitung DBZ, 8|2010, S. 20f. Jaeger, Falk: Next 3 Stadia 2012, Jovis Verlag, Berlin (Germany), , 2012 External links Website Engineering companies of Germany Construction and civil engineering companies of Germany Companies based in Stuttgart 1980 establishments in West Germany Construction and civil engineering companies established in 1980 German companies established in 1980