Understanding the Millau Viaduct

The Millau Viaduct is the most spectacular link on the A75 freeway linking Clermont-Ferrant to Béziers. To date, more than 60 million vehicles have crossed the 2640 m of what is the highest motorway bridge in the world, resting on the Causse du Larzac to the south and the Causse Rouge to the north.
A look back at the birth of one of the major architectural structures of the 21st century.

Millau: on the road to vacation

For years, vehicles wishing to connect Northern Europe with Spain had little choice. To make the journey without leaving the freeway, they had to take the A6, the A7 and then the A9, making a detour.
To avoid this detour, there was only one solution! Take the A71 then the A75, but these vehicles agreed to do without the freeway at the Tarn, at Millau, and exposed themselves to interminable traffic jams, particularly during the vacations.

A desire on the part of the French government

So, to avoid traffic jams, the French government decided to complete the A75. So as not to isolate the town of Millau, the Tarn crossing was set very close to the Sud-Aveyron city, at a point where the valley stretches for up to 2.5 km.

A modern, aesthetic solution

With the state and local authorities involved, and the choice of location determined, all that remained was to define the nature of the project. The idea of a viaduct at Millau had been around since the early 1980s.
A call for tenders was issued by the French government, and the multi-hauban structure was chosen in 1996 from among four other solutions. Conceived by engineer Michel Virlogeux and designed by British architect Lord Norman Foster, the choice of elegance and modernism won over the public authorities. All that remained was to give shape to this extraordinary project.

The project’s completion: a major challenge

To successfully build the structure and put it under concession, the French government launched a new call for tenders. Numerous construction giants responded. But in the end, Eiffage’s combination of concrete and steel was chosen in 2001. Compagnie Eiffage du Viaduc de Millau is responsible not only for the construction, but also for the operation of the viaduct.

Construction of the structure was to be completed in record time: just 3 years.
A major challenge for the prime contractor.

“The adventure begins”

On December 14, 2001, trucks and cranes invaded the Tarn valley, and construction of the viaduct was launched. Several hundred workers were hired to meet the 3-year deadline.

Raising the piers

Before the “deck” could be laid, i.e. where the cars would travel, the 7 piers had to be built. In order to build them quickly, the number of crews and cranes was multiplied by 7.
The result was that in just a year and a half, all the piers were completed, including the famous “P2”, which set the world record for the tallest pier at 245 m high.

The North-South junction

While the piers were being built, the metal parts that make up the deck were transported to either side of the valley. In fact, the deck was prepared on both sides of the valley to meet above the Tarn at a height of 270 meters!
The “clavage” or junction of the North and South sections required the invention of new construction techniques, notably for the jetting of the deck.
On May 28, 2004, the junction of the deck was completed, no less than 18 jetting operations having been carried out to make the operation a success.

The end of the work

Three months later, the pylons and 154 guy wires were in place, and the loads were evenly distributed. All that remained to be done was to install the road signs, road surfacing, lighting and safety systems, so that on December 14, 2004, the President of the French Republic could come and inaugurate the structure.
The project was a success! Completed on time and internationally acclaimed.

Commissioning

On December 16, 2004, the viaduct goes into service. It now takes just 20 minutes to cross the Tarn valley.
But crossing the world’s highest bridge isn’t free!