Cut & cover building pit
ALIDA Grundstücks-Gesellschaft mbH & Co. KG
Bothe Richter Teherani, Hamburg
- Top down construction method, prestressed partial covers
- Peripheral diaphragm walls
- Depth: up to 24 m
- Base area: 12,000 m²
- Inner city location
- Framed by the Alster Lake, by existing buildings and underground stations, streets and alleys, utility lines
- Time: 2003 - 2004
- Building costs: c. 25 mill. EUR
- Our scope:
civil and structural engineering
A big hole next to the Alster lake.
New dimensions in Hamburg's city centre: those who today enter the Europa Passage at street level from Mönckebergstrasse not only have seven stories above them, but seven more below!
An enormous excavation in the middle of the city; the deformation sensitivity of the surrounding buildings; high water pressure: all these things and much more demanded of the engineers a very special wealth of ideas, creativity and precision. A new programme, developed in our office, was used to calculate deformation in the ground. Deformation measurements obtained during construction confirmed the values of the preliminary calculations with a high degree of approximation.
Method of construction: the building pit was surrounded by an 80 cm thick slurry wall embedded some 30 metres deep in the hydrous mica clay. The excavation was reinforced from the inside. Construction took place from the top down. The three upper reinforcement layers were preloaded against the retaining wall using presses. The uppermost reinforcement layer is a steel truss. Below that, there are five reinforced concrete partial covers. These were later expanded to storey ceilings.
These days there is almost nothing to tell visitors to the Europa Passage of the work involved in the production of the building pit. At any rate, it’s not possible to see anything anymore. That clearly means: Engineering mission accomplished!