At TU Wien, an alternative to resource-intensive stencils for the construction of concrete domes was developed. It is now used in the test dome of the Austrian Federal Railway Infrastructure.

Concrete shells are effective structures but are not resource efficient. The construction of a concrete dome template requires a lot of labor and materials. Dr. Benjamin Kromoser and Professor Johann Kollegger of the Institute of Structural Engineering invented a very resource-efficient alternative construction method at TU Wien called “Pneumatic Forming of Hardened Concrete (PFHC)”. A simple air cushion and additional post tension ribs transform the slab into a hyperbolic shell. Therefore, complex space bending templates and frames are redundant. The Austrian Federal Railway Infrastructure (ÖBB Infrastruktur) is currently constructing the first 1:2 test building in Carinthia, southern Austria, which will later serve as an event canopy.

“Pneumatic forming of hardened concrete” construction method

The function of the construction method is relatively easy: first, a flat concrete slab with a wedge-shaped outlet is cast. After the concrete has hardened, the air cushion placed under the plate expands and tensions the ribs after tensioning until the final shape is reached. The glass fiber reinforced plastic rod used as a reinforcement absorbs the strain occurring in the concrete slab. If the manufacturing precision of the flat plate is high, the construction method can produce a very precise concrete casing. This method also saves up to 50% of concrete and 65% of the necessary reinforcement.