Berlin, Germany – The German capital city is growing! With over 3.5 million inhabitants, Berlin is the biggest city in Germany and even decades after reunification, construction is still booming. New developments in the inner city are in particularly high demand. One such development is a 30,000 m² shopping and activity center in the Moabit district of Berlin Mitte – a once working-class district – on the grounds of the former Schultheiss brewery, steeped in tradition.
The client, HGHI Schultheiss Quartier GmbH & Co. KG, is also building 6,000 m² state-of-the-art offices – almost half of which are listed as historical monuments. For the new-builds, BAUER Spezialtiefbau GmbH and JV partner Keller Grundbau GmbH constructed two complex excavation pits with a total area of 11,000 m² in confined inner-city conditions from May 2015 to November 2016.
As the leading technical JV partner, Bauer constructed mixed-in-place walls that were up to 16.5 m in depth, including tie-back anchoring and micro piles for uplift prevention in the building. The contract also included extensive demolition work in the partly historically listed area, foundation engineering and groundwater control. Bauer also sealed the entire subsoil with a silicate gel base – a particularly efficient process for foundation sealing in Berlin with high execution reliability.
Many of the risks associated with creating the base with the jet grouting technique, such as imperfections rising due to obstacles such as wood or large rocks, are eliminated by the use of the silicate gel. It encloses the obstacles and avoids the subsoil loosening due to air ingress, which leads to a subsequent reduction in the bearing behavior of the uplift elements.
During the works, the specialist foundation engineers repeatedly encountered previously unknown well structures on the site of the former brewery and had to adapt their procedures accordingly. The Design Department of BAUER Spezialtiefbau GmbH was responsible for the execution planning. Many devices and equipment from subsidiaries and branches of BAUER Maschinen GmbH were used: two RG pile drivers from RTG Rammtechnik, as well as an anchor drilling rig from Klemm and a MAT mixing plant.