Dillinger heavy plate for the
Viaduc de Millau

The small town of Millau, in the South of France, is located directly on Autoroute A 75, the country’s second important north-to-south link, after the Autoroute du Rhône. The town achieved fame – or perhaps “notoriety” would be the better word – as a result of the gigantic traffic jams formerly occurring there in the summer months, as a result of the gap in the autoroute caused by the wide and deep valley of the Tarn. Since late-2004, these have been a thing of the past, thanks to a bridge of superlatives in every sense, designed by Sir Norman Foster. At 2,460 meters in length, and a height of 343 meters, this is the world’s highest such structure, topping even the Eiffel Tower. In addition, it is also the world’s longest multiply cable-stayed bridge.

For this now world-famous viaduct, Dillinger Hütte supplied the almost unimaginable quantity of 43,000 tonnes of heavy plate. The center box girder of the carriageway deck and parts of the towers, amounting, in all, to nearly 50 percent of the structure, were fabricated from DI-MC 460, a thermomechanically rolled fine-grained structural steel. The high mechanical strength of this material reduced the weight of the deck structure and thus facilitated the use of the place-and-thrust method for construction of the bridge. The excellent weldability possessed by DI-MC 460 made it possible to dispense with preheating of components prior to welding. DI-MC thus directly enabled the Viaduc de Millau to achieve yet another world record – an incredibly short construction period of only thirty-eight months, and costs of only 400 million Euro.