Construction Project
North-South Connection Berlin-Press. Caissons Gleisdreieck |
Location
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Client
- DB Projekt GmbH Knoten Berlin
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Planning
- HOCHTIEF AG (special contract award)
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Investment volume
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Construction period
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Contracted services for BMG
- Section 55.8 HOAI-General construction management
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Structures constructed
- Construction of 6 caissons in part sections (L = 360 m) as four-cell tunnel cross-section with an excavation volume of 130,000 m³
- Caisson cross-section (W/H = 38.00-60.00/14.20-17.80 m)
- Lowering depths 19.20 to 26.80 m at a lowering rate of 0.30 to 1.00 m/day
- Caisson covers 5.00 to 9.00 m
- Caisson surface areas 2,280 to 3,400 m²
- Lowering weight about 25,000 to 30,000 t
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Special features
- Construction of an earth model in the approach cutting on well-compressed subgrade
- Concreting of the lowering chamber and the wedge-shaped edges with 8 cm overcut
- Concreting of the four-cell tunnel structural parts and integration of airlocks for people and material in the structural parts for supplying the pressurized workplaces
- Excavation of the earth model under atmospheric conditions before beginning lowering
- Lowering of the construction using flushing guns and pump removal of the ground emulsion
- Filling the undercut during the lowering procedure using bentonite as lubricant
- Working under pressurized conditions at a pressure of up to 2.3 bar for protection from groundwater
- Fixing of the caissons after reaching final depths, protected by sealed beds and sealed walls, by demolition of the caisson front walls and sealing of the standard joints
- Lowering precision target/actual = 15/5 cm
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Utilization
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Construction
- Construction of the caissons using concrete impervious to water
- Concrete used for construction 80,000 m³
- Reinforcing steel used for construction 11,000 t
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