Striatus 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. The bridge, developed by the Block Research Group (BRG) at ETH Zurich and ZHA Computation and Design Group (ZHACODE), in collaboration with incremental3D (in3D) and made possible by Holcim, 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.

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’.