Architecturally, a dome is a strong, stable shape. But building a dome out of stone or concrete is a labor-intensive, expensive endeavor.
Engineers Johann Kollegger and Benjamin Kromoser from the Vienna University of Technology have come up with a construction method that’s cheap and simple: inflating slabs of precisely shaped concrete that join together when they rise up. The technique could make it possible to erect strong, inexpensive buildings in impoverished areas or to quickly and cheaply build everything from concert pavilions to highway underpasses.
They started with a form for the concrete that consisted of several segments. Next, they poured concrete into the segments, which were separated by wedge-shaped spaces. When the material hardened, an air cushion below made of plastic sheets sealed together was inflated. Steel cables were tightened around the segments to ensure they raised in unison. The wedge-shaped spaces allowed the segments to fit together perfectly when the structure was raised. Afterward, the structure was plastered.
In the experiment, a 9.5-foot dome was built in about two hours.
Kollegger and Kromoser think that a variety of different shapes can be built using the pneumatic wedge method. After seeing the results, the Austrian Federal Railways commissioned a deer pass over two high-speed rail tracks in Carinthia.
via Vienna University of Technology
Credit: Johann Kollegger and Benjamin Kromoser, TU Vienna