AJ100 Innovation of the Year 2022 winner revealed

Striatus is the first of its kind: an arched masonry footbridge composed of 53 3D-printed hollow concrete blocks assembled without mortar or reinforcement.

The 16 x 12m structure, by Zaha Hadid Architects (ZHA) in collaboration with public research university ETH Zürich’s Block Research Group, was exhibited in the Giardini della Marinaressa at last year’s Venice Architecture Biennale and was unanimously chosen by judges as the inaugural winner of the AJ100 Innovation of the Year award. The bridge’s digital concrete fabrication combines the time-honoured principles of traditional vaulted construction with advanced computational design, engineering and robotic manufacturing technologies. The result is a ‘super-lightweight’ bridge that eliminates waste by using material only where structurally necessary.

ZHA explains that the name Striatus reflects the bridge’s structural logic and fabrication process. Using a special concrete ink developed by Swiss building materials giant Holcim, concrete was 3D-printed in precise layers orthogonal to the main structural forces to create a ‘striated’, compression-only structure.

The bridge is easily maintained and demountable, and designed according to the principles of ‘reduce, re-use and recycle’. It took 84 hours to print all the blocks. The construction of the bridge, including foundation casting, assembly and stair and deck installation, took just 35 days. Striatus boasts a highly expressive form and is clearly more than a one-off prototype. ZHA is already working on two commissions for similar permanent bridges, one of which is in the UK.

The AJ100 judges called it an ‘outstanding’ achievement and, with concrete’s enormous global carbon footprint in mind, said its lean design approach had huge potential to do more with less, slashing the embodied carbon of bridges and other structures, including flooring systems. 3D-printing concrete can reduce the use of the material by up to 70 per cent.

‘This is refreshing and well-considered,’ said one judge. ‘Architects tend to think innovation means apps … what I like about this is that it takes a fully-integrated view which goes from materiality, to compression structures, to aesthetics and talks about a massive reduction in material cost all the way through.’ Other judges admired the holistic and rigorous approach taken by ZHA and the wider team, the bridge’s reinterpretation of a simple but highly efficient compression system and the project’s ‘ambition to reach beyond what it is now’.

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