Statics

The extraordinary statics of the Central Building are completely depicted in the shell construction. Some of the force curves can still be read off the walls, which show different degrees of inclination outward or inward. For this statics it was necessary that every single finished floor was a self-contained intermediate stage of construction in which the shell had to be stable. At the same time, the complete building statics were only given with the last roof beam. For the construction of the outwardly inclined walls, massive auxiliary foundations had to be poured in order to support the drying out walls. 


The ceilings of the individual floors are filled with orthogonally arranged Cobiax cavity balls to reduce the weight of the ceiling. In places almost twice as thick as classic reinforced concrete ceilings, these ceilings are nevertheless considerably lighter, so that many supporting pillars could be dispensed with. This creates an unusually open feeling of space, especially on the ground floor. In addition, due to the lightweight construction method, fewer supports were required for the intermediate construction phase and the construction time could be reduced due to shorter drying times.

A special feature is the free-floating seminar centre, which is a lattice girder construction. A classical reinforced concrete construction method would have been too heavy here. The framework consists of the so-called upper chord, lower chord and the girders on both sides. These components could not be built in one piece, but were assembled from sections about three meters long. Here, too, enormous quantities of supports were required for the individual intermediate construction stands, whereby after their removal the entire part of the building was lowered by only 1 cm. One of the lower chords of the framework runs through the auditorium, all other chords are held against the walls of the research centre in the centre of the building. For fire protection and structural reasons, the individual girders of the framework had to be encased in concrete; their connection consists of individually manufactured steel composites. Only such ingenious production made this extraordinary part of the building possible. 

The Central Building was built by hand. For example, countless steel wires had to be braided for the unusual shapes before they could be poured into concrete. The statics of the building was therefore not only a challenge for architects and inspectors, but for all the craftsmen involved.