Tanzbrunnen Dance pavilion (I.4)
It covered a dance floor that was raised as a round island over an artificial pond. Although it was planned to remain only for one season, it was subsequently erected during the summer for many years thereafter because of its great popularity. Six graceful, 10 m-long construction masts support a 1,000 m2 membrane made of cotton sailcloth. The roof membrane was made from 12 identical segments that, based on the four-point sail principle, had each segment mirroring the bend and angle of another. The 12 segments are arranged in a star formation around a central ring and mirror each other in pairs so that their outer borders undulate. The 28-m2 central opening over the middle of the dance floor is held fast with a cable tension ring that is suspended from the masts with ridge cables. Tow cables secure the placement of the ring and prestress the membrane. A replica of this star-shaped tent, built by the firm L. Stromeyer & Co, was also the highlight of the International Eucharistic Congress in Munich in 1960. After the undulating tent in Cologne, Frei Otto designed temporary tents for Interbau in Berlin in 1957, for which the methods of curving originally flat membranes were tested on many projects, including the exhibition hall for the special exhibition “Die Stadt von morgen” (The city of tomorrow) and the Interbau Café. The latter was reused in 1958 at the Swiss Exhibition for Women’s Work (SAFFA) in Zurich as an “island café”.
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