Extension of the Städel Museum in Frankfurt am Main
The architects won an international competition in 2008 with their design concept of placing the generously sized new museum hall underneath the Städel garden instead of above ground like former extensions.
The height of the exhibition hall ranges from 6 to 8.2 m and 195 circular skylights supply the underground area with natural light. The freely shaped concrete ceiling shell rests on only twelve inner columns as well as on the surrounding reinforced concrete walls of the rectangular subterranean structure measuring about 76 m x 52 m. The ceiling curves upwards forming a dome shape with a height of up to 2.26 m in a central area of approx. 26 m x 26 m. The thickness of this reinforced concrete construction varies between 35 bis 60 cm, depending on load and strain.
The building phases of this extraordinary concrete construction are illustrated by the photo series below.