Mont-Saint-Michel Access Bridge
Designed by the architect Dietmar Feichtinger to be the thinnest possible link between the peninsula and the main-land, the Mont-Saint-Michel (Manche) footbridge, built by Eiffage Construction Métallique and Eiffage Travaux Maritimes et Fluviaux, a subsidiary of Eiffage Travaux Publics, is light and elegant.
In fact, although the steel deck with its 124 beams, 267 spacers and 510 brackets, weighs 1,600 tons, it is less than one metre thick, including concrete slabs and surfacing. The 134 supporting posts spaced at twelve metre intervals are just 24.4 centimetres in diameter and appear as thin as stilts. The 1.2 metre thick concrete piles in which they are embedded are invisible being anchored 42 metres below ground level in the sand, so as to withstand the wind and tidal forces.
© Raphaël Schaeffer.
The various sections of the metal frame were prefabricated at the Eiffage Construction Métallique factory in Lauterbourg (Bas-Rhin) and installed at a rate of two per week. Eiffage Travaux Maritimes et Fluviaux was then responsible for installing the 257 concrete slabs that are 3 metres wide and 25 cm thick, varying in weight from 9 to 12 tons, which line the platform. Site workers also installed the two abutments at each end of the access bridge, i.e. the solid foundations of reinforced concrete in which the metal frame is embedded and that ensure the transition onto dry land, a wastewater pumping station and fire emergency reservoir.
Operations prior to reception of the access bridge took place in early June 2014. Access was granted by the owner, the Syndicat Mixte de la Baie du Mont-Saint-Michel, to the company responsible for the shuttle service - Transdev – in mid-June 2014, and the bridge was opened to pedestrians in late July 2014.