Trade Fair Hall in Hanover

The hall has an area of 27,400 m2 and was designed for the World Exposition in 2000. The column-free internal space has a minimum clear height of 12.5 m and is covered by a roof structure consisting of a flexurally rigid grid of tubular steel girders. For visual reasons, the structure is raised towards the centre. The roof is supported at each corner of the building and in the middle of the long faces on three-storey concrete cores that accommodate the necessary ancillary spaces. The main loads are borne by the cores. A much smaller portion of the loading is conveyed to the ground via the flexibly jointed columns behind the plane of the façade. These also serve to transmit the horizontal loads from the self-supporting structure of the outer skin. The glass façade, which encloses the hall on all four sides and allows daylight to penetrate to the interior, is translucent in the areas of the cores. In this way, the clear spatial articulation of the hall is revealed on the outside. The structure is based on a 7.5 ? 7.5 m grid and is closed at the top by a system of prefabricated timber coffers that alternate with roof lights in the central areas. Each of the bays of the roof contains three coffers, which are supported by the upper chords of the grid of girders. Six aerodynamic Venturi elements mounted on the roof over ventilation stacks in the cores induce low-pressure conditions that result in vitiated air being sucked out of the hall at ground level. Fresh air is fed in at ceiling level.