The roof of the ‘Städel Museum’ is currently being converted into a visitor terrace. The terrace is to be accessed via two steel spiral staircases. The 50 steps of each staircase are housed in 12 metre high cylinders weighing approx. 8 tonnes. Using a mobile crane, the steel spindles were lifted and fitted into the designated openings. As the construction work took place while the museum was still open, the planning required particular care in terms of the construction sequence, construction progress calculations and noise levels.
In order to install the heavy steel spindles, existing 60 cm thick load-bearing and bracing masonry walls had to be interrupted and partially demolished. A ring beam was cast under the roof to provide bracing. In addition, two new reinforced concrete slabs were installed and an existing timber beam slab was reinforced with concrete to create a timber-concrete composite slab.
Extension of the Städel MuseumFrankfurt, Germany