green house for the Botanic garden of Aarhus
Function of building
Degree of enclosure
Fully enclosed structure
Temperate - cold winters and mild summers
Number of layers
Type of application of the membrane
Primary function of the tensile structure
- Rain protection
- Sun protection
- Thermal insulation
An elliptical cupola structure forms the envelope for a new green house in the botanical garden of Aarhus. It is used for plant cultivation thus tropical and subtropical plants can be grown in an environmentally controlled area. ETFE cushions are used, which do not block the UV radiation.
The primary structure consists of ten arches in each direction, longitudinal and transversal. The maximum arch span is approx. 41m and the maximum arch rise is approx. 17.5m. The arch distance varies form the dome base to the dome apex (between 1.6m and 4,9m). The dome is symmetric by one axis, and covered with ETFE-cushions. They are double layer cushions towards west, north and east and triple layer cushions with integrated shading toward the south and in the zenith of the dome.
Steel brackets are attached to the main steel structure to carry the aluminium extrusion profiles, which form the perimeter of the ETFE-cushions. The aluminium profiles follow a 3 dimensional curve, and are bended and drilled in 2 directions. Under the extrusion profile is a gutter to accumulate condensate. Some of the cushions are used for pneumatic shading. These are the triple layer cushions, with outer and middle layers which are printed. The middle layer can be moved by changing the air pressure from the in- to the outside. When the inner layer is close to the outer layer, the shading is more effective. The rest of the cushions are transparent with double layers. In total there are 34 triple layer cushions and 90 double layer cushions, which are supplied by a central blower unit. Different pressure levels can be applied, normal, half snow and full snow. Furthermore the blower system provides a differential pressure to form and to move the middle layer of the cushions. In the zenith of the roof two triangular windows are also covered with ETFE- cushions. These can be opened to provide natural ventilation or as smoke exhaust in case of fire.
Description of the environmental conditions
Material of the cover
Main dimensions and form
Covered surface (m2)
Maximum height (m)
Duration of use
Temporary or permanent structure