Building structures from ice and snow is probably something everyone has tried in their youth. Today, using ice as a building material is also something which is being discussed by scientists. The research group supervised by Prof. Kollegger of the Institute of Structural Engineering is looking into ways of building large-scale, stable domes made of ice. Following a thorough preparatory and research phase, a new ice dome construction method is now being put to the test in Obergurgl — a world first. This structure, showing more than 10 metres free span, is now home to a bar — for as long as the temperatures are low enough.
Using ice as a building material has actually been done before: entire ice hotels have been built in e.g. Scandinavia.  "In most cases though the spans of the structures are small or the ice is not a load-bearing component and merely acts as cladding for the actual construction", explains Prof. Kollegger. The team of Vienna University of Technology has developed an ice dome which presents a stable and free-standing safe structure, and does not require additional support using other building materials. Theoretical calculations and several experiments have been carried out in this area over the past few years and, thanks to the latest technology, ice structures which are large and stable enough to actually be used as serviceable buildings can now be built.

Slow deformation process – like a glacier
First, a 20 cm-thick plate of ice is cut into 16 segments. These two-dimensional segments have then to be transformed into a three-dimensional structure. The University research team takes advantage of one property of ice, known as "creep behaviour". If pressure is applied to the ice, it can slowly change its shape without breaking.  Glacial creep functions similarly. "The segments of ice are placed on stacks of wood. Then, under the load of its own weight, the ice begins to change shape all by itself, resulting in a curved dome segment", explains Sonja Dallinger, research assistant at the Institute of Structural Engineering and on-site manager of the Obergurgl construction experiment.
The greatest challenge that had to be faced was the prevention of any breakage of the individually curved segments when assembling the dome. To solve this issue, a wooden tower was erected and the dome segments were held together by means of steel chains. The wooden tower could only be removed once all the segments had been positioned correctly and the ice dome stood on its own.

Austria's coolest bar
The ice dome was constructed in front of the spa area of the Hotel Alpina in Obergurgl and is  presently being used as an ice bar. The drinks are definitely pretty cool — and of course it's up to you whether or not to wear a cocktail dress!

Further information:
Prof. Johann Kollegger
Institute of Structural Engineering
Vienna University of Technology
1040 Vienna
T.: +43-1-58801-21202
M.: +43-664-605882121
<link link_email>johann.kollegger@tuwien.ac.at

Dipl.-Ing. Sonja Dallinger
Institute of Structural Engineering
Vienna University of Technology
1040 Vienna
T.: +43-1-58801-21262
M.: +43-664-605882121
<link link_email>sonja.dallinger@tuwien.ac.at