The Phoenix bridge: Improving circularity of 3D-concrete-printed unreinforced masonry structures

Dell’Endice A., Bhooshan V., Lombois-Burger H., Megens J., Bodea S., Eiz H., Chen T., Regnault de la Mothe L., Nana S., Sanin S., Bürgin T., Bhooshan S., Van Mele T. and Block P.
FABRICATE 2024
UCL Press
Copenhagen
2024

This paper describes the design, fabrication and construction of Phoenix, a permanent 3D-concrete-printed (3DCP) unreinforced-masonry (URM) pedestrian bridge built in Lyon, France, in 2023. The design of Phoenix starts from the experience and knowledge gained in the realisation of Striatus, the 3DCP URM bridge prototype built in Venice, Italy, in 2021. The combination of 3DCP and URM principles enables the design of discretised compression-only structures and represents a strategy to increase sustainability, reduce material consumption and allows reusability and recyclability of the structure. Due to the rapid growth of large-scale 3D concrete printing in academia and practice and the industry demand for the robustness and durability of this structural system, this project attempts to solve some of the criticalities encountered in the realisation of Striatus, aiming to improve several aspects including circularity and carbon footprint. Research has been conducted at different levels: the concrete ink's sustainability, which uses aggregates recycled from the disassembled 3DCP blocks of Striatus, the overall structural performance, the 3D-printing process, material waste reduction and assembly strategy, which maximises the usage of standard off-the-shelf falsework components instead of custom-made single-use parts. This project represents a further step in the research field of unreinforced-masonry structural logic applied to 3D concrete printing. It shows promising strategies to reduce the environmental impact of concrete, increase the circularity of small infrastructures such as footbridges and push the boundaries towards the industry.