‘Thin shell’ floors could cut carbon in construction

British researchers have developed a new vaulted floor that could reduce the use of concrete and help reduce the environmental footprint of the construction industry.

dr. Paul Shepherd of Bath University stands on the thin concrete floor of the ACORN project

The thin shell vaulted floor was developed by a team of structural engineers, mathematicians and manufacturing experts from the Universities of Bath, Cambridge and Dundee. Compared to a traditional flat slab floor, the innovation would use 75 percent less concrete and 60 percent less carbon in the construction.

The curved vaulted structure is covered with standard raised floor panels to create a flat surface. Made by the UKRI-funded ACORN (Automation of concrete structures) research project, the vaulted floor design takes advantage of the “inherent natural properties and strengths” of concrete, the team said.

dr. Paul Shepherd, principal investigator for ACORN and a reader in the University of Bath’s Department of Architecture and Civil Engineering, said: “Achieving the net-zero targets ratified recently at the COP26 conference will require significant change by the construction industry, which is responsible for about half of the UK’s total emissions.

“Since concrete is the second most consumed material in the world after water, and its production contributes to more than seven percent of global CO2 emissions, the easiest way for construction to start its zero-load journey is by using less concrete. to use.”

Currently, most building floors use thick flat slabs of solid concrete, which rely on the flexural strength of concrete to support loads. Concrete is not good at withstanding the stress caused by bending, so these floors need steel reinforcement. Instead, ACORN’s approach is to use concrete for what it does best: resist compression.

By placing the material only where it is needed and ensuring it works under pressure, the ACORN design uses less concrete. Researchers noted that the mold can be impractical to create using traditional temporary formwork, so they have also developed an automated adaptive mold and robotic concrete spraying system that can be used in an off-site factory environment.


In addition to this new manufacturing style, the team developed custom software to optimize floors for a particular building design and control the automated manufacturing system to produce them.

Since the floor is made off-site, it must also be transported to the site and then assembled. The team split the large floor into nine movable pieces and developed a joining system to join the pieces together.

The ACORN team said they have also incorporated reversible joints so that the floor can be dismantled at the end of the building’s life and reused elsewhere, promoting a circular economy in construction.

The viability of the system has just been demonstrated to ACORN’s industry partners by constructing an entire 4.5m x 4.5m thin shell building at the University of Cambridge’s NRFIS Laboratory of Civil Engineering.

Early results suggest that ACORN’s approach could yield “significant carbon savings,” according to the team, and future research is likely to yield more as processes are optimized. Each piece took just half an hour to make, despite being the first of its kind, and the entire floor took a week to assemble — future commercial versions could be manufactured more quickly in dedicated industrial facilities, researchers believe.

Abhishek Maheswari
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