Deutsche Messe AG Hannover
Herzog + Partner BDA, Thomas Herzog, Hans Jörg Schrade, München/D
IEZ Natterer GmbH, Wiesenfelden; Ingenieurbüro kgs, Hildesheim
Built for the EXPO 2000 in Hanover, the EXPO roof was a major innovative timber structure in terms of dimensions, construction and design. The image of the roof as a primary form of shelter was the decisive conceptual idea. An architectural sculptural compositionas an exhibition pavilion, as well as outdoor areas and bodies of water, were created under the shelter of a large roof, which impressively symbolised the motto of the world exposition: ‘Mankind, Nature, Technology’. This large roof with a total area of 1,600 square metres is made up of twelve individual canopies, each covering a floor area of 40 x 40 metres at a height of more than twenty-six metres. Each of these canopy roofs is divided into several elements: a tower-like structure, a central steel connectingelement, four cantilevered beams, and a double curved gridshell with four shell surfaces. The tapering tower structure consists of four silver fir trunks and triangular bracing panelsof glulam. The beams that cantilever nineteen metres are hung from a steel pyramid that forms the central connecting element. The loads from the ribbed shell and the cantilevered beams are directed into the steel pyramid, and from there to the tower construction. The surfaces of the ribbed shell, which is a stacked plank construction, are covered with a translucent membrane that, on the one hand, provides protection against the weather while on the other, allowing constant air flow. At the time of its completion, this roof, which, despite its large, structurally necessarydimensions, makes an elegant impression and indeed appearsalmost to hover, was, with a span of almost twenty-eight metres on the main diagonals, the largest stacked plank constructionever carried out. In addition to demonstrating the performanceof the material, it also shows the diverse possibilities of designing with wood.