ETH doctoral student develops foldable formwork for building ceilings

(CONNECT) Unfold Form is the name of the lightweight and reusable formwork for vaulted concrete structures. It was developed by architecture doctoral student Lotte Scheder-Bieschin in Philippe Block's ETH research group. According to an ETH report, it saves up to 60 percent concrete and up to 90 percent steel compared to conventional ceilings.

Unfold Form consists of thin, flexible plywood strips. They are connected to each other by textile hinges and can be unfolded like fans. Four such forms are quickly and easily assembled in a wooden frame to form a load-bearing formwork with spikes. The concrete is poured on top. "The concrete absorbs these corrugations as ribs," says the inventor. "These ribs help to support loads."

Once the concrete has hardened, the formwork can be removed from below, folded up again and used again. According to the information provided, the entire system for the prototype weighs only 24 kilograms, but can carry up to 1 ton of concrete.

"In addition to the material, you only need a template for the shape and a stapler." The material for the prototype cost 650 francs. As the researcher emphasizes, the formwork can be produced and erected without specialist knowledge or high-tech. This means it can be used worldwide and with limited resources, for example in developing countries. This is because the demand for new builds is very high there.

The second prototype was cast on site by the South African partner company nonCrete, which is committed to sustainable buildings and affordable housing. "The innovative formwork system," says Scheder-Bieschin, "will one day be used to build high-quality, dignified and sustainable homes in South African townships." ce/mm