Hamburg
Reconstruction of a double vault
Hamburg, Germany / 08.2017 - 12.2017
In the area around the Deichtorhallen in Hamburg, six historic double vaults, known as casemates, were restored beneath the tracks used by local and long-distance trains. A reinforced concrete frame structure with deep foundations was constructed for the rehabilitation. PORR special civil engineering carried out the additional piling work using large-diameter bored piles.
Facts & Figures
Company
PORR Spezialtiefbau GmbH
Type
Rehabilitation, Retrofitting foundations
Runtime
08.2017 - 12.2017
Large-diameter bored piles for the retrofitting foundations of historic casemates in the railway sector
Retrofitting foundations beneath existing railway tracks
The casemates are located directly beneath the railway lines to the south of Hamburg Central Station. As part of the rehabilitation, the new supporting structures had to be constructed on deep-set piles. The ground conditions consisted of fill, marl, clay containing organic matter, as well as sands with a groundwater table close to the surface. The foundation work for the piles was carried out in the load-bearing sands.
Large-diameter bored piles using the grab method
Once a stable working level had been established, the large-diameter bored piles were constructed using the grab method under water load. The piles reached lengths of up to 20.45 m. Construction took place within the existing vaulted structures and was adapted to the existing spatial constraints.
Work under restricted headroom
The clear internal height of the vaults was only around 5.50 m. In some places, there was barely a few centimetres of space between the boom of the equipment used and the vault ceiling. Due to the restricted height, drill pipes and reinforcement cages could only be inserted in sections. The individual elements were therefore installed in sections, each approximately 2 m in length.
Work in the vicinity of railway infrastructure
The renovation work was carried out in the vicinity of existing railway facilities. Deutsche Bahn’s overhead line systems were located in the immediate vicinity. The equipment used was prepared in accordance with the project-specific requirements. In parallel with the underpinning work, further construction activities took place within the casemates, including reinforced concrete work carried out by the contractor responsible for building construction and structural engineering.
Retrofitting foundations for the rehabilitation of the casemates
The large-diameter bored piles driven form the foundation for the new reinforced concrete frame structure within the historic double vaults. The retrofitting complements the existing structure and creates the conditions for the continued use of the building beneath the railway tracks.
