Triangular steel pylons frame views of the Rhône and the Alps. The Illarsaz competition proposal brings existing and new structures together through a cable-stayed system with a shared pylon on the island.
The competition proposal ‘1 + 1 = 1’ brings an existing footbridge and a new one into a continuous structural strategy. Rather than treating the existing cable-stayed crossing as a separate object, it becomes part of a phased transition towards a new crossing of the Rhône. A shared central pylon on the island connects the two bridge sections.
The cable-stayed system is designed to remain stable during asymmetric construction stages, allowing the crossing to evolve without elaborate temporary supports. The triangular steel pylons also shape the experience of the bridge: their orientation frames the river, the island and the Alps. Exposing the structure makes the path of forces legible while opening views towards the surrounding landscape.
co-struct developed both architecture and structural engineering for the 2025 open competition. The entry was not awarded a prize and is documented as a competition proposal.