Concrete is typically the default building material for tall structures, thanks to its strength and cost-effectiveness. But there’s one big trade-off: Heft. Conventional concrete construction requires significant mass and steel reinforcement, which takes up space and consumes excess material.
But by applying techniques commonly found in Gothic cathedrals, researchers in the Department of Architecture at ETH Zürich–a science and technology focused university in Switzerland–have developed an alternative to steel-reinforced concrete floors that’s 70% lighter than conventional construction. They hope this discovery yields space and cost savings, and helps new buildings become more environmentally friendly.
When contractors build reinforced-concrete floors, they typically pour concrete over a rebar grid to create a solid, flat slab. ETH’s floor system, in contrast, looks more like a honeycomb pattern of solid and void and requires no reinforcement.
The researchers began by analyzing historic building techniques, like Catalan vaults, a Roman building technique that uses a subtle arch to span spaces, and flying buttresses, a reinforcing feature on the exterior of Gothic cathedrals that counteracts the lateral force an arch exerts on walls. Their floor system is made up of large, molded concrete modules that jigsaw together to form the shape of a Catalan vault. Each module is composed of a lattice-like web of ribs that distributes weight across the floor.
While the design is still in the experimental stage, ETH Zürich’s stress tests revealed that the floor structure could support more than 2.5 times the weight that Swiss building codes require. According to a release from the University, researchers plan to use the system to build a two-story guest house to see how it could be applied.
Concrete manufacturing has significant environmental impacts, including huge amounts of carbon emissions. Many building science researchers are investigating alternatives to using mass quantities of the material, like timber construction. Thanks to research like ETH Zürich’s, the construction industry might be able to wean itself off concrete sooner rather than later.