Bridge Over The Rhône

The viaduct’s layout was to be rectilinear with a long, slightly convex profile. It would have crossed the Rhône, the Stockalper Canal, the Tonkin railway line and several roads, making it an important structure on the Transchablaisienne H144 highway.

The project developed for the tendering process was a cable-stayed bridge with access spans supported by continuous girders. The bridge had pylons located behind the dikes of the river and crossed the Rhône with a span of 111 m (364 ft.), providing a generous and open structure across the river.

To avoid structural bearings, the deck was supported monolithically on the piers and pylons similar to a floating bridge. It consisted of a deck slab stiffened by two longitudinal ribs. The ribs were located below the cables on the cable-stayed spans, and they came together above the piers on the side spans.

The H-shaped pylons were equipped with tie plates to accommodate using continuous cables. The stay cables consisted of a bundle of high-strength steel strands arranged in a 180 mm (7 in.) diameter sheath. The cables were arranged in a harp pattern and blended well with the site to give the structure a tranquil look.

The balanced cantilever method was to be used to install the cable-stayed span over the Rhône, eliminating the need for bank modifications or temporary pilings. This would have reduced the risks associated with installation across the river.