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General information

  • Location address
  • Location country
  • Name of the client/building owner
    Suisse Projects (kplan AG)
  • Function of building
  • Degree of enclosure
    Fully enclosed structure
  • Climatic zone
    Temperate - cold winters and mild summers
  • Number of layers
  • Type of application of the membrane
  • Primary function of the tensile structure
    • Space defining elements


Three domes with a primary steel structure made of radial lattice girders are covered with membrane on both sides. On the inside, towards the bath, a silicone coated glass membrane forms the space of the inner ceiling. On the outside a PTFE coated glass membrane covers the whole structure forming a continuous surface. The steel structure is not visible any more. Especially the detailing with a linear clamping on a perpendicular steel flat, which is also covered by a membrane strip, makes the steel structure disappear. The whole space within the two membrane layers is under air pressure, so that the membrane has its quite flat curvature towards the outside and follows the form of the cupolas. In the air space between the membrane envelope, a low E foil with an aluminum coating spans between the steel girders and reduces the loss of thermal radiation. Also this foil is not visible from the outside and is translucent so that even with the three layers of membrane and foil a slight daylight illumination exists. With artificial light from the inside the cushion volume, the atmosphere within the cupolas can also be influenced, and the appearance of the whole building gets interesting from the outside.
To continue the outer appearance of the membrane in the lower area in front of the concrete structure, the membrane structure changes from a cushion with synclastic curvature into mechanically tensioned panels with anticlastic curvature. This leads to an optical change in the base.
A special challenge was the intersection of the water slides with the membrane panels. In total 6 water slides and the big "Tornado" start inside the slide dome, penetrate the membrane panels and continue their curvy run outside before they return to the inside of the dome again. The slides have to be isolated from all membrane forces, but must be included in the airtight structure. A clamped steel ring in the shape of the membrane couple the membrane stress. For tightening a so called "bellow", a membrane stripe with a small radius was clamped between steel ring an slide to tighten the gap.

Description of the environmental conditions

Material of the cover

  • Cable-net/Fabric/Hybrid/Foil
  • Type (code)

Main dimensions and form

  • Covered surface (m2)

Duration of use

  • Temporary or permanent structure