Decarbonizing Concrete Construction : Case of the Phoenix 3D Printed Footbridge and Learnings for Engineering and Architecture.

Traditionally conservative, the construction sector must now demonstrate innovation given the climate emergency in order to reduce the carbon footprint of structures. 3D printing of concrete appears to be an emerging technology with an immense potential to address sustainability challenges in the modern construction sector. It offers significant advantages and can play a key role in the decarbonization of building structures. The Phoenix 3D printed footbridge presented in this study, built in Lyon, France, in 2023, introduces further sustainability and circularity benefits resulting from applying traditional unreinforced masonry structural logic to 3D concrete printing. It is the second of its kind after Striatus exhibited in Venice Biennale in 2021, thus building on key learnings from Striatus to push further the boundaries of innovation. It combines the creative and innovative design of architects and engineers according to the rules of the art to save materials, reduce carbon footprint, boost circularity, and extend service life. The authors' goal at large is to show the feasibility of this innovative footbridge and to share learnings over the whole construction process that will help engineering, architecture, manufacturing and construction sector in general to accelerate progress towards net zero.