Sternwellenzelt, Membrane roof structure in Deutz, Cologne, Germany

The Sternwellenzelt is a radial membrane tent roof over the circular dance floor of the Tanzbrunnen in Deutz, which stands as an island in an artificial water basin. Six slender lightweight masts, each 10 m long, carry a roof of twelve equal segments joined around a central ring with a 28 m² opening, so the outer edge runs in a wave. The original cotton canvas of about 1000 m² was replaced in the 2001 restoration by coated polyester, now giving 500 m² of shelter.

Frei Otto designed the radial membrane roof for the Tanzbrunnen dance floor at the 1957 Federal Garden Show in Cologne. The dance floor itself, a round island over an artificial water surface, had been built by architect Josef Op Gen Oorth in 1950. Planned for one year only, the popular roof was dismantled each winter and re-erected in summer; after years in storage it was rebuilt in 2001 and restored, with the cotton canvas replaced by coated polyester. Otto later developed membrane construction further, culminating in the Munich Olympic site roof with Günter Behnisch.

The dance floor beneath the roof was built in 1950 by architect Josef Op Gen Oorth as a round island above an artificial water surface. The tent was made for the 1957 Federal Garden Show and proved so popular that it was dismantled each winter and re-erected each summer for several years.

The dance floor stands as a round island above an artificial water surface, reached within the Tanzbrunnen grounds in Deutz. Six slender masts, each 10 m tall, carry the roof, which was rebuilt in 2001 after years of complete dismantling. The roof was originally planned for the 1957 Federal Garden Show only and for years was taken down in winter and re-erected in summer.

The roof was meant to last only for the 1957 Federal Garden Show, but it proved so popular that it was dismantled each winter and re-erected each summer for several years. After a long period in storage, the canopy was rebuilt in 2001 and restored, with the original cotton canvas replaced by coated polyester.