Concrete beams are getting “smarter,” with new designs that reduce waste, cut CO₂ emissions, and improve safety.
Traditionally, concrete structures are built directly on-site, through a process often slow, imprecise, and wasteful. Poor quality control often leads engineers to use far more material than necessary (up to 40% extra) while construction sites generate large amounts of waste.
A new promising approach, developed by the team at the École nationale des ponts et chaussées (Institut Polytechnique de Paris) within the Liaison project, shifts production to factories and combines advanced design, robotics, and digital tools: the result is a prefabricated 7-meter long beam that uses significantly less concrete, around 20% in current designs.
A key innovation is the beam’s optimized shape, which includes carefully designed internal cavities that reduce material without compromising strength. These complex forms are created using 3D concrete-printed molds tailored to each beam. At the same time, a more sustainable concrete mix has been developed, replacing part of the natural raw materials with recycled construction waste.
The beams are also “smart” because they include built-in fibre optic sensors that continuously monitor their condition over time. These sensors track strain and temperature, allowing engineers to detect potential issues early and better understand how structures perform throughout their lifespan. To verify the structural concept, these beams have been installed in a pedestrian bridge on the ACCIONA machinery park in Noblejas, Spain: early tests show that the new beams are just as strong as traditional ones, while offering major environmental and efficiency benefits.
If scaled up, this innovation could help reduce the environmental impact of construction – one of the world’s most resource-intensive industries – while delivering safer and more reliable infrastructure.
