Sprayed concrete for artistic shells

The 1000-seat main auditorium of the Goetheanum at Dornach, Switzerland centre of the worldwide Anthroposophical Society, was entirely rebuilt in 1996/98. The project included the installation of interior elements that reduce the auditorium volume, decorate it artistically, and improve its acoustics. Essentially they comprise seven large columns along each of the side walls, whose capitals support an architrave 30 metres long and seven metres high. The surfaces of the column bases, the capitals and the architraves are sculptured. These elements are made of a load-bearing steel structure and sprayed concrete of special composition that was treated with hatchets after setting. The sprayed concrete had to meet very demanding requirements. The working conditions and the structural shapes, many of which are very complex, called for exceptional skill on the part of the nozzlemen.