A simple solution for constructing concrete floors in a more climate-friendly way, has been developed by a Swiss research team.
Known as Unfold Form, the vaulted, unreinforced concrete and foldable multiple-use formwork system uses geometry to shape a much thinner sectioned floor which uses up to 60% less concrete and 90% less steel than a conventional reinforced concrete floor slab.
The lightweight, robust, and reusable formwork design was developed by architecture PhD student, Lotte Scheder-Bieschin who is associated with the Block Research Group at ETH Zurich.
Unfold Form consists of thin, flexible plywood strips connected by textile hinges which can be unfolded like a fan. Four of these compact units can be rapidly assembled within a wooden frame to create a sturdy, zigzag shaped mould onto which concrete can be poured directly.
After the concrete cures, the formwork can be easily detached from underneath, folded away, and stored for its next use. While the system used for the prototype weighs just 24 kg, it can support up to one tonne of concrete.
“The Unfold Form formwork can be produced and assembled without specialised knowledge or high-tech equipment,” Ms Scheder-Bieschin said. Currently, formwork for non-standard concrete shapes typically requires digital fabrication which creates barriers for sustainable concrete construction in developing countries.
Ms Scheder-Bieschin demonstrated the system’s simplicity by assembling it herself during her pregnancy. “I wanted to ensure my design was simple enough for anyone to build, regardless of their circumstances,” she explained.
The formwork can be produced cheaply – the only addition to the materials are a template for the shape and a stapler, according to its inventor. The materials for the prototype cost the equivalent of AU$1134. The system is being commercialised through VAULTED AG.
About the author
Desi Corbett
Desi is the Editor of Concrete in Australia and at the helm of our magazine for 8 years. She was behind the Institute's weekly news bulletins from 2016-2021 and is now writing our focused news items. Desi has been an engineering news and features journalist/editor across all disciplines since 2013 - part of a 30-year career writing for a wide range of industries.