Oral+Presentation

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The Millau Viaduct is an enormous cable-stayed road-bridge that spans the valley of the river Tarn, near Millau in southern France.



Designed by the structural engineer Michel Virlogeux and British architect Norman Foster, it is the tallest vehicular bridge in the world, with one mast's summit at 343 metres (slightly taller than the Eiffel Tower and only 38 m shorter than the Empire State Building)



The Millau Viaduct consists of an eight-span steel roadway supported by seven concrete pylons. The roadway weighs 36,000 tonnes and is 2,460 m long, measuring 32 m wide by 4.2 m deep, making it the world's longest cable-stayed deck. The roadway has a slope of 3% descending from south to north, and curves in a plane section with a 20 km radius to give drivers better visibility.



For nearly thirty years prior to the construction of the Millau Viaduct, the A75 autoroute had remained unfinished. Before the bridge, a crossing of the River Tarn was provided by a bridge situated in the valley bottom, in the town of Millau. Millau was then known as a ‘great black spot’ of motoring. Kilometres of congestion and hours of waiting to transit the town recurred each year with the great surge in traffic in summer months. These slowdowns meant that the advantages of the autoroute were lost. The A75 was meant to be a positive example of spatial planning, a modern, direct highway entirely free along its 340 km length. As it was, the traffic from the autoroute brought pollution and danger to the town of Millau.



Construction began on 10 October 2001 and was intended to take three years, but weather conditions put work on the bridge behind schedule. A revised timetable aimed for the bridge to be opened in January 2005. The viaduct was inaugurated by President Chirac on 14 December 2004 to open for traffic on 16 December, several weeks ahead of the revised schedule.