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B. Kromoser, J. Kollegger:
"How to inflate a hardened concrete shell with a weight of 80 t";
Talk: IASS 2017 Annual Symposium, Hamburg, Deutschland; 2017-09-25 - 2017-09-28; in: "Interfaces: Architecture . Engineering . Science", A. Bögle, M. Grohmann (ed.); (2017), 1 - 7.

Concrete shells are efficient structures, which highly utilize the construction material. Unfortunately, the formwork required for the construction of concrete domes is currently labor and material intensive. A very resource efficient alternative construction method called "Pneumatic Forming of Hardened Concrete (PFHC)" was invented at TU Wien as described in Kromoser and Kollegger [1], [2]. A simple air cushion and additional post-tensioning tendons transform a flat concrete plate into a double curved shell. Thus, the complicated spatially curved formwork and the framework are not required any more. Currently the construction method is first practically applied for the construction of a concrete shell in Carinthia in the south of Austria on behalf of the Austrian railways (ÖBB), which will later serve as event canopy.
The cupola has a length of 26.5 m, a width of 19.1 m and a height of 4.2 m. The structure is used to improve the construction technique for a first large application to build a deer pass in 2017 over the twin-track railway line Koralmbahn. Recently the transformation process of the test cupola could be successfully finished. The test cupola weighs 80 t and was lifted with only 20-22 millibar from the flat plate to the spatially curved shell. The very smooth surface results from a fitted geometry optimization (Pachner et al [3]). In the next work steps in the beginning of 2017 additional reinforcement and an additional concrete layer will be applied and some areas will be cut away. The final building should already be used for events in summer 2017.
In the present paper the construction principle, the design process, the project schedule and the construction process are explained.

Concrete shell, inflatable structures, geometry optimization, flexible formwork, Pneumatic Forming of Hardened Concrete