IN Brief:
- Eiffage Métal is fabricating a 75m movable span weighing 625 tonnes at its Lauterbourg plant.
- The bridge replaces an end-of-life crossing over the Caen-to-sea canal for Ports de Normandie.
- Completed spans will travel by barge via Rotterdam, the North Sea and English Channel in early 2027.
Eiffage is assembling the replacement Colombelles swing bridge at its Lauterbourg fabrication plant in Alsace, where a 625-tonne movable steel span is taking shape ahead of a river and sea journey to Normandy. The structure will replace the existing crossing over the Caen-to-sea canal, which has reached the end of its operational life.
Eiffage Métal is fabricating both the movable and fixed spans for Ports de Normandie. The principal movable section measures 75m long, 16.8m wide and 7.2m high. Its dimensions required it to be manufactured in two major sections before the components were moved outside the Lauterbourg production building on 29 and 30 July for assembly.
The project also includes a fixed span measuring 35.2m long and 14.5m wide. Eiffage says fabrication of that element is approaching completion, while the movable span still requires final welding, protective coating and equipment installation before it can leave the plant.
The bridge is consequently being treated as both a fabrication project and a heavy-logistics exercise. Once work at Lauterbourg is complete, the finished spans are scheduled to leave by barge in early 2027. The route will take them from the port of Lauterbourg to Rotterdam before crossing the North Sea and English Channel to Colombelles.
Moving the main span largely intact avoids breaking an exceptionally large piece of structural steelwork into road-transportable elements for reassembly beside the canal. It also shifts part of the delivery risk into the transport operation, where lifting arrangements, temporary support, barge capacity, weather and marine sequencing all have to be coordinated with the final installation programme.
The existing Colombelles bridge carries a route across the canal linking Caen with the sea and has reached the end of its service life. Its replacement will remain movable so that vessel traffic can continue to use the waterway, while the new crossing will provide greater space for walking and cycling.
For the fabrication team, the movable function adds another layer of precision beyond conventional bridge steelwork. The completed span has to align with bearings, civil structures and operating equipment at Colombelles, meaning dimensional control during welding and assembly has a direct influence on the later installation and commissioning stages.
Carrying out that work at Lauterbourg provides access to permanent fabrication facilities, lifting equipment and controlled production processes before the bridge reaches the more constrained canal site. Large sections can be welded, inspected and coated before transport, reducing the amount of structural assembly required within the final construction zone.
That does not remove temporary-works requirements from the manufacturing phase. The two principal sections had to be moved from the production building and supported externally before they could be joined, with their size preventing conventional completion inside the plant. Final finishing must now continue around the assembled structure before the transport operation begins.
Eiffage Métal is working on the project alongside Eiffage Génie Civil, ETMF, Arcadis, Setec ISM and Lavigne & Chéron. The delivery team reflects the range of disciplines required for a movable canal crossing, where structural fabrication has to integrate with civil engineering, mechanical systems, highway arrangements and the operating requirements of the waterway.
The choice of Lauterbourg also illustrates how fabrication location can be determined by logistics rather than simple geographical proximity to the final site. The plant is a considerable distance from Normandy by road, but access to navigable waterways allows a span of this scale to travel substantially intact rather than being divided into smaller transport sections.
That makes barge transport part of the construction strategy rather than merely the final delivery method. Completing more of the structure within the factory reduces the number of high-value steelwork operations required at Colombelles, while marine transport provides the means of preserving those larger fabricated assemblies between plant and site.
The immediate programme remains focused on welding, painting and equipping the movable span, alongside completion of the fixed section. Early 2027 will move the project into its next distinctly different phase, when the structure leaves the controlled fabrication environment and the emphasis switches to marine transport, heavy lifting and final installation over the Caen-to-sea canal.
