Office building in Berlin

Building use

Office building

Country/Region

Germany

Overview

The building is the headquarters of the company GSW and the whole development is a composition of 5 buildings, the taller of which being a very slim curved slab, about 85 meters tall. The new tower is connected at each floor with the pre-existing one, thus limiting the floor to floor height to 3,25 m. The thin slab allows all offices to be naturally ventilated but also imposes some constraints due to the limited space available.

Basic information (construction date, number of stories, gross floor area, adopted design code, engineer(s), Contractor(s), etc.)

Construction date: 1996-2000
Number of stories: 22
Gross floor area: 33,000m2
Adopted design code: –
Engineer(s): Arup GmbH
Contractor(s): Gemeinnützige Siedlungs- und Wohnungsbaugesellschaft Berlin, mbh, Berlin

Issue and/or innovation

The vertical structure of the tower has to occupy as little space as possible, while at the same time recreating inside the office spaces the same soft and smooth shape of the whole building, without hard corners.

Reason for composite solution

The original scheme was with long cantilevers and parts of the building had to be hung from a truss beam at the roof level. In this case, the vertical supports would have been in tension, thus with a very thin profile.
During the tender stage, the contractors proposed significant savings by modifying the structural systems, so that the tension elements were transformed in columns under compression.

Specific solution/technical details

The desire to have exposed concrete of the slim columns dictated the choice of a composite system made of encased steel profiles. To further decrease the slim shape, the concrete layer had to adapt somehow to the H steel profiles it was connected to. From here the very unique shape of the composite columns.

Impact or effectiveness

The softened and rounded shape of the H composite beams visually creates, for the side, a third vertical line which makes the column to appear thinner and slimmer.