Offices for members of the Bundestag are situated in a 30-storey building raised on pilotis.
There is a podium from the basement to the third storey. One longitudinal side of this low-rise building is set forward from the base of the high-rise block, while its other three sides are recessed beneath it.
The rectangular concrete core braces the building and supports the inner ends of the floor beams, which are spaced at 3.75 m centres and span from the core walls to the external columns, which are of 650 x 650 mm square box section. The core is not situated in the centre of the building and the span of the beams on the two narrower faces and on one of the longitudinal faces is 7.50 m. On the other longitudinal face the distance from the core to the external columns is 15.00 m, which is halved by an additional row of internal columns carrying longitudinal beams. Above the 18th floor of the building these internal columns have been moved 3.75 m inwards towards the core in order to obtain more depth for the halls. These columns are supported on a storey-height lattice girder in the 18th storey.
At third floor level every alternate external column is intercepted by, and supported on, a box girder 2000 mm in depth. The columns under this girder, spaced at 7.50 m centres, have a length of 13.20 m on three sides of the building, that is, where the podium building is recessed under the main high rise block.
The floor beams carry 12 cm thick precast concrete slabs spanning 3.75 m. For structural and fire protection reasons it was necessary to ensure continuity of the floor slabs. So the slabs were recessed at the top to have projecting reinforcement exposed at the supports. Additional reinforcement was introduced here and the joint completed with in-situ concrete.
Notes:
Bundestag Áóíäåñòàã
continuity n. íåïðåðûâíîñòü
half v. äåëèòü ïîïîëàì