SFRC Underwater Slab for the Potsdamer Platz (PP) Berlin: Fid-Bau Portal

SFRC Underwater Slab for the Potsdamer Platz (PP) Berlin

Falkner, Horst / Hinke, Ulf

Daimler-Benz (DB) the well-known car-producer decided to make the largest immobile investment in Europe, in the heart of Berlin. DB bought a large area in 1988, just near the wall. Nobody knew at that time that the wall would be taken down by the East Berlin people in November 1989. Since our office have made an engineering task in Stuttgart for DB, at a building in 8-m-deep groundwater, for DB it was clear that the same engineer should make the job as well in Berlin. Nobody knew at that time, that the water conditions of those two projects were completely different. In the project we handled before, the groundwater could be lowered by pumps. DB wanted the same concept for the PP. But in Berlin the water conditions are completely different. The depth of the water for the building pit was between 20 to 22 m and the water could not be lowered. The level of the groundwater was not allowed to be touched because the Berlin people get all their drinking water from the perfect filtered groundwater. The idea of a steel fibre concrete slab could be a solution for this project. However, we had no guideline, no code and no experience. Therefore, our procedure to design a safe and stable SFRC underwater slab was based on tests in scale but also on tests in the field with real dimensions. Our main task was to convince the authorities from the Senate of Berlin, DB and the German Railway Authorities. With this concept we got the agreement to build the deepest pit ever constructed before in a depth of 22 m.