Millau Bridge is in southern France and crosses the River Tarn in the Massif Central Mountains. The central pillar is higher than the famous French icon, the Eiffel Tower. The bridge was opened by President Jacques Chirac. In his speech he praised the design saying that it was a ‘monument to French engineering geniuses and ‘a miracle of equilibrium’.
The bridge was entirely privately financed and cost 394 million Euros. It is the tallest bridge in the world with one mast’s summit at 343.0 metres (1,125 ft) above the base of the structure. It is the 12th highest bridge deck in the world, being 270 metres (890 ft) between the road deck and the ground below.
Millau Viaduct is part of the A75-A71 auto route axis from Paris to Béziers and Montpellier. The first plans were discussed in 1987 by CETE, and by October 1991, the decision was made to build a high crossing of the Tarn River by a structure of around 2,500 m (8,200 ft). During 1993–1994 the government consulted with seven architects and eight structural engineers.
In late 2001, the first stone was laid. By spring 2002, the first piers of the Millau Viaduct were raising skywards. At the same time, the anchorage points of the deck (the abutments) were appearing.
A few weeks were all it took to carry out the earthworks. The first work on the steel deck of the bridge commenced in the summer of 2002, and on March 25, 2003, the first deck section, which was 561 feet long, was driven out into open space. Seventeen others followed suit, at an average rate of one rolling out every four weeks.
The 3 year construction period had many unique challenges, the most significant being the unusual launching of the roadway. Instead of cantilevering the road deck outward in small sections from each of the 7 tall pylons, the deck was constructed on flat land on the north and south sides of the bridge in two large sections.
Hydraulic jacks on the tops of the piers were then synchronized to move the entire deck out over the valley in small increments of about 2 feet (600 mm). Both sides eventually met over the Tarn River.
To make this method work, massive temporary intermediate piers were built to prevent bending of the thin deck since the cable stays and masts above the roadway would not be erected until the entire deck was in its final position.
Before the bridge was built way down the valley, this created a huge line of traffic, and was one of the reasons why the bridge was built. At mostly it was 500 people in the work during construction. It was created a dedicated cement factory.
There were 9 building sites, one for each pillar and where the bridge began and ended. The 7 pillars of concrete were built first. They built four meters a day, and it was used sliding formwork.
When the 7 pillars were finished, it was set up temporary piers between the 7 pillars, so that it would be pushing out the bridge deck from each side. When the two bridge decks met in the middle, the tower was installed on top of the pillars and then the wires are attached. It was set up railing that was as tall as a truck.