The project is jointly built by ETH Zurich, Zaha Hadid Architects, Holcim and In3D. The project is located at the Holcim Innovation Center in Lyon, France. The bridge is assembled from concrete 3D-printed components.
In 2021, a similar bridge was built in Venice, Italy. This is the iteratively updated second version. The completion of the bridge marks another step forward in concrete cyclic construction. The bridge's application of unreinforced masonry structural logic has made significant progress in 3D-printed concrete, mainly in terms of circular construction, reduced environmental impact, and structural robustness.
Compared with the first generation of 3D-printed concrete bridges, carbon emissions have been reduced by 25%, mainly due to the use of Holcim's new 3D-printed concrete mix ratio, local materials, and solid waste utilization. During the construction process, Reliance on disposable formwork or scaffolding was reduced and materials from the first-generation bridge were recycled.
The bridge's geometric design eliminates the need for steps, making it easier for walkers to navigate. The bridge also features a handrail system that is held in place by balustrade arches.
To improve assembly accuracy while minimizing disposable scaffolding parts, the bridge's assembly logic was completely redesigned. Modular formwork assemblies were developed integrating a minimal wooden grid structure with standard reusable steel beams to minimize the volume of disposable timber elements. 3-6 3D printed concrete elements are precisely assembled on each scaffolding module, which is then lifted onto a pre-installed scaffolding tower.
Assembly follows a predefined sequence, starting from the center towards the bracket, leaving a few centimeters of clearance from the foundation. This strategy was adopted to control manufacturing tolerances and assembly inaccuracies at mid-span and push them towards the final contact surface with the bracket so that they could be compensated for by filling the gap with mortar before demoulding.
