This sports complex in Berlin was planned by the French architect Dominique Perrault as part of Berlin's candidacy for the 2000 Olympic Games. When the Games were awarded to Sydney, the City of Berlin decided to reduce the size of the project and to go ahead with the construction. The velodrom was completed in 1997, the pool in 1999.
What is unusual about Perrault's project that he has hidden the buildings in the ground. There is no visible facade. The complex is elevated only slightly above its natural and artificial surroundings. Its central cores are the two underground structures, the pool and the velodrome, covered with a steel grid on which the reflection of the light creates an effect much like a pool of water.
Perrault has used this solution elsewhere, in the false ceilings of Paris National Library. The grids are positioned on the same level as the skylights; they are divided into strips which may be rolled up and connected to one another by a series of springs, which are mobile to permit frequent maintenance. The weight of the grids, anchored to steel supports, means that they need no further connections. The complex was built with eight thousand tons of steel, about half of which was used for the roof of the velodrome alone. The velodrome roof is 4 metres high and made up of a grid of trusses with a diameter of 142 metres. Inside it are technical services and a series of walkways required for maintenance. The entire structure is supported by 16 reinforced concrete pillars.
The sports complex was built in the Prenzlauer Berg area, a little hill raised above the level of the city, in order to avoid the water table, which is quite high in Berlin (2.5 metres below ground level). But a further raising, up to a height of 5 metres, was required in order to permit the whole complex to be built underground. The average depth of the excavations was 13 metres, and so the round surface emerging one metre above ground level is 13 metres above the base of the hall. This shining "disk" lets daylight in from the side and is the most unusual, characteristic aspect of the entire complex.
On his design, Perrault commented: "There is the disappearance of the architecture and the appearance of a landscape and always with the same idea in mind, that is to say, the one of mastering a fundamental material of architecture,the void, even if it is abstract. How can one build with the void, a simple emotional power? How can one build voids that are not places that separate the different parts of the city, the places of sociability, of civic life?"
