Berlin
‘LUV & LEE’ residential complex
Berlin, Germany / 02.2022 - 06.2022
On Regattastraße in Berlin, the ‘LUV & LEE’ residential complex was built in the second row, comprising 25 owner-occupied flats, one commercial unit and 28 underground parking spaces. PORR Spezialtiefbau’s Eastern Region was awarded the contract for the construction of the trough excavation, including the DSV sealing slabs, earthworks and clean fill layer. The sealing slabs were designed by the company’s in-house specialist civil engineering design team.
Facts & Figures
Company
Stump-Franki Spezialtiefbau GmbH
Type
Turnkey construction pits, Sealing slabs
Runtime
02.2022 - 06.2022
25 flats on Regattastraße
Construction between existing buildings and the water table
The residential development is being built on an inner-city plot in the Köpenick district of Berlin. To construct the future buildings, it was first necessary to excavate a construction pit, which was carried out in accordance with the site’s existing constraints. The construction pit was constructed as a trough-type pit with a free-standing soil-mixed wall and deep-seated DSV sealing slabs. Together, these two elements form the vertical and horizontal waterproofing of the construction pit.
Soil mixing wall for the construction pit
Around 2,200 m² of freestanding soil mixing wall with embedded steel sections was constructed to enclose the construction pit. Due to the shallow excavation depth, no back-anchoring was required. In the soil mixing method, the existing subsoil is mixed with a cement slurry and formed into a new structural material directly on site. The overlapping of individual columns creates a continuous construction pit wall. Construction took place within an existing residential area and subject to the constraints of the neighbouring buildings. As the subsoil is incorporated into the construction pit wall directly on site, the work could be carried out within the limited construction site area. This facilitated site logistics on the inner-city plot.
DSV sealing slabs beneath the excavation pit
As the groundwater table was above the planned excavation depth, DSV sealing slabs were constructed beneath the future construction pit using the jet grouting method. The sealing slabs integrate into the soil-mixed wall and, together with it, form the waterproofing of the construction pit against the surrounding groundwater. This created a closed system of vertical and horizontal waterproofing as the foundation for the subsequent earthworks and structural work. The lance layout plan for constructing the sealing slabs was drawn up by PORR special civil engineering planning and tailored to the subsoil conditions and groundwater conditions of the site.
Working in confined inner-city conditions
The construction pits were carried out in the immediate vicinity of existing residential buildings and within a limited construction site. The soil-mix retaining wall, DSV sealing slabs, excavation and clean-up layer were executed in co-ordinated construction phases. In doing so, consideration had to be given to both the space constraints on the site and the existing buildings and infrastructure in the surrounding area.
The foundation for the residential complex
Completion of the construction pits created the conditions necessary for the subsequent structural works. Even before the future buildings came to define the site’s appearance, the foundation for the LUV & LEE residential complex and its associated underground car park was laid beneath the ground surface.
