Vallourec provided the seamless steel tubes that support the new bridge of Mont Saint-Michel in north-western France, which opened to the public on 22 July 2014. The 760m long bridge was built using, among other things, some 400 tons of seamless steel tubes produced in Vallourec’s Aulnoye-Aymeries plant (France). These tubes form the 124 slender columns that anchor the bridge deep in the seafloor, rendering solid concrete piers superfluous. The tubes, up to 9.5m long, have a diameter of 244.5mm and wall thicknesses of between 40mm and 60mm. The thinner-walled tubes are used at the beginning and end of the structure, and the thicker-walled ones in the middle-section, where the load factors are greater. A special anti-corrosion coating protects them from aggressive saltwater.
The bridge, for which construction began late 2011, is part of one of the most elaborate French ecological restoration projects for the conservation of this national monument. The restoration project aims at letting the site revert to being an island some days a year and rendering the access car-free. The old road causeway has been replaced by a new dyke, and continuing from the end of this dyke is the bridge made of Vallourec tubes, which extends straight to the mediaeval abbey.