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Long-spans amplify the collaborative relationship between architects and engineers

By Sara Hart

The cargo hangar

Everything old is new again. It’s been 50 years since Germany manufactured its famous Zeppelins. Now a company called CargoLifter AG is developing airships (named CL 160s) to transport goods—generators, turbines, and oil drills—up to 176 tons over a distance of 6,000 miles. By definition, these flying cranes are technically blimps—helium-filled with no rigid skeleton. Without a metal chassis, so to speak, the CL 160s are lighter and, therefore, able to carry more cargo weight.

CargoLifter Airship Hangar, Brand, Germany Architect: SIAT Architektur + Technik Structural engineer: Arup Date of completion: 2003 Roof span: 1,190 by 738 feet Consultants: Klöffel (building services) The design team minimized the weight and cost of the hangar’s enormous doors (above) by cladding a horizontal, vertical, and diagonal grid with corrugated-metal sheeting. The PVC-coated stressed membrane (top and above) that covers the structure spans 102 feet between the trussed tubular arches in the warp direction and between the ridge truss and edge cable attached to the arch bases in the fill direction. A small prototype for the CargoLifter sits inside the hangar (in the center, above). External horizontal props between the top chords of the arches (above) restrain any torsion that might be caused by eccentrically connected membranes. The sliding doors (shown partially opened below) are supported by a 3-foot-thick concrete slab. The doors can be completely opened in only 15 minutes. Photography: © Palladium (top and bottom ); Michele Janner/Arup (middle)

The company needed a hangar with a volume of 194 million cubic feet in which to build and store these airships. At 1,191 feet long by 225 feet wide and 351 feet tall, CargoLifter AG got “the world’s largest self-supporting enclosure.” Far from a merely utilitarian shelter, the hangar has many clever elements in which the architecture is integrated into the structure—or vice versa, depending on one’s viewpoint. This suggests a palpable collaboration between architect and engineer at the grandest of scales.

Every detail has multiple functions and meanings writ very large. According to Arup, who engineered it, the hangar imitates the blimps’ design in the quest for lightness. Five steel arches and a ridge girder support the barrel-shaped midsection. The arches, trussed and cross-braced to withstand wind and torsion, are anchored in U-shaped, reinforced concrete plinths above grade, which also act as covered entrances that, in turn, protect employees from snow sliding off the high fabric roof. The arches are glazed between the top chords, allowing daylight into the building. These “arches of light” also serve as egress beacons, guiding the way to emergency exits at the termination of each arch.