The Bridge That Changed the Map of Europe

Video hosted and narrated by Fred Mills. This video contains paid promotion for Odoo.

THE MILLAU VIADUCT should not have been possible. 

It is the tallest bridge in the world. In fact, even today in all of Europe there are only four skyscrapers taller than it. It soars 340 metres above the Tarn valley and stretches for 2.4 kilometres.

To celebrate the 20th anniversary of the bridge’s opening, back on this very day - 16 December - in 2004, we sat down with renowned architect Lord Norman Foster in a special interview to trace the viaduct’s journey from impossibility to icon.

Above: The bridge was higher than any skyscraper in Europe at the time.

Lord Norman Foster is one today’s most accomplished architects. You may know some of his other projects: the Gherkin, the Reichstag, and nearly every famous Apple store, including of course Apple Park.

His practice continues to define the skylines of America, London, and Europe.

But it is this project that may be his most breathtaking.

This is the bridge above the clouds. The Millau viaduct.

France divided

France has a problem and its name is Massif Central. It is a beautiful, rugged mountainous terrain that covers about 15 percent of the country.

It also severs France in two. These same gorges, rivers and forests make it an incredibly hard landscape for anyone to cross coming from the north to south of the country, or from northern Europe to Spain.

For centuries this divided Europe and meant that central France could not develop due to a lack of adequate transportation links.

The roads and trainlines that did exist were mostly single lane and would have to dip and rise into these steep valleys, or make massive detours. Many villages did not have proper connections to the outside world at all.

Above: Massif Central cut France in half.

In the summer months those travelling from cities like Paris to the south of France would have to come through Millau, a picturesque village surrounded by beautiful countryside. During this time it became the worst bottleneck in Europe. The congestion would add 5 hours to any journey and extend 20 kilometres in both directions.

In the 1980s the French government wanted to solve this problem. Massive freeways were built through the region, but the question remained: what to do about the worst bottleneck. What to do about Millau?

Should the village be bypassed altogether? Should a bridge be built over the Tarn river? But where?

A bridge, not over a river but the entire valley

Geologists and specialists worked for years to figure out where on earth this bridge could go. The valley was wide and steep and prone to landslides. It was a nightmare.

Engineer Michel Virlogeux and his team then had a lightbulb moment: what if the road didn’t go into the valley at all? What if the bridge went over it entirely?

It was an incredibly bold idea and something that had never been done on such a scale before. The French government thought Virlogeux was insane and the bridge was put to rest… for the time being.

If it hadn’t been for the success of another bridge, miles away, the Milau Viaduct might never have happened.

Virlogeux was working on the Pont de Normandie which was completed in 1994. It is an incredible cable-stayed bridge that crosses the Seine right before it empties into the ocean. Seeing this bridge convinced the French government that the Milau Viaduct might just be possible after all.

Virlogeux had one condition. If this bridge was going to cross the Tarn Gorge it would have to add to the landscape, not take away from it. It would have to be beautiful.

This is where architect Lord Norman Foster came in.

A marriage of architecture and engineering

“You only get one first impression. And it was just a meeting of minds. I mean, when we started to engage with each other and talk about the idea of the competition,” Lord Foster told us of his first meeting with Virlogeux.

“It's rare that you engage with somebody. And when you're talking issues of structure or aesthetics that you find you're on the same wavelength.

“The chemistry was and is fantastic.”

An international competition was held to decide on the design for the bridge. It was not especially common for architects to be involved in massive national infrastructure projects like this. Lord Foster would have to prove his worth.

Above: Foster and Virlogeux's design won hands down. Image courtesy of Nigel Young / Foster + Partners.

“I think it's very rare. I think the government agency that was tasked with the idea of the competition.

“They realised environmentally it was so sensitive that there should be from the outset a visual aesthetic coupling to the engineering.”

It was decided a cable-stayed bridge would be chosen over other types of bridges, like a more traditional suspension bridge. Cable-stayed bridges are more efficient at carrying heavy loads, and they can support a much more slender deck so it’s much better to look at.

Everything about the viaduct was to minimise its visual impact.

Lord Foster even reduced the number of piers to seven from the nine that Virlogeux initially proposed.

When it came time to present their design to the jury the team decided to lead with Lord Foster. This was very unusual for a civil infrastructure project, especially in France where engineers are often more famous than architects.

“Interestingly, the engineers in the team insisted that I present the project. Now, obviously the bridge is a work of engineering and I don't pretend never could profess to be an engineer.

“But the idea that I presented it perhaps came out of the shared philosophy, to reinterpret the bridge over the Tarn as being a bridge connecting two plateaus across the entire valley.

“Celebrating the heroic proportions of this great landscape valley, that was really a philosophical decision shared by all the team.”

Foster and Virlogeux’s design won hands down. They proposed something more than just a bridge. They proposed an extension of the natural beauty of the valley itself. A philosophical concept, not just a bridge.

Now the real work began.

The invisible bridge

Once plans for the bridge were officially announced there was an outcry from locals and environmentalists. Like Lord Foster, many feared the natural beauty of the landscape would be ruined by a colossal bridge taller than the Eiffel Tower.

There were also fears that while the bridge would assuage the bottleneck, it could negatively affect the economy of Millau.

There was now more pressure on Foster and Virlogeux than ever before.

This enormous, record breaking bridge would also need to be invisible.

Above: The bridge beginning its "launching" operation. Image courtesy of Nigel Young / Foster + Partners.

At this time, these piers would be taller than any building in Europe, and they would be sitting in open fields with no other structure around them for scale, they would look even more gigantic. To balance this, Lord Foster wanted them to disappear into the sky.

“The idea that the column is faceted and is like a tuning fork and you can see through it that was simultaneously visually slimming it, but at the same time responding to the expansion and contraction in a more economic way. So performance, economy, integrity, optimize structure all go hand in hand.”

The towers would get more slender as they rose, dividing into two prongs, more or less halving from 24 metres wide at the bottom to 11 metres at the top. While this is aesthetically pleasing it served another purpose as well.

Fighting the wind

The Millau Viaduct had another obstacle to being built: the wind.

Wind speeds could blow through the Tarn Gorge at more than 130 miles an hour. The two prongs in each of the piers allowed for the deck above to move but be stable while the wind could pass through the gaps. It also allowed for the deck to expand and contract as metal does on warm days.

This was another example of the harmonious relationship between engineering and architecture that this bridge required.

The colour of the bridge

But there was a pressing issue that kept Lord Foster awake at night: what colour should the bridge be?

It sounds simple enough, but the choice could make or break the entire project. The viaduct couldn’t exactly be bright red like the Golden Gate Bridge.

Above: The colour of the bridge was one of the most important decisions in the design process. Image courtesy of Nigel Young / Foster + Partners.

“That's not a cosmetic decision. It has enormous visual impact.

“If you decide the landscape is the protagonist is the main player, then that will lead you to doing those cables dark because.

“They would disappear into the landscape, but they would be dominant against the sky. If you make them light. They would disappear into the sky.”

Lord Foster realised most people viewing the viaduct would be looking at it from below, either from the village or from the deck as they drove across it. The bridge would need to blend with the sky. Not with the valley around it.

In the end he chose grey.

“I was absolutely terrified. I was physically sick with apprehension. Was it the right decision? It's binary. There's no halfway.”

Building it from the ground up

Spacing the piers was its own challenge. They would have to be equidistantly spaced, but also structurally efficient, buildable, and economical.

“There's a trade off between the cost of a span because the longer the span generally, the more expensive it becomes, but then the shorter the span, the more piers. And each pair has four deep piles and each pier obviously has a cost.”

Excessively long spans would create difficulties and extra costs when constructing the deck, yet each pier represented a massive cost in itself. In the end, the team compromised with a span of 342 metres in between each pier.

The piers, each one taller than a skyscraper, then began their construction. GPS technology was used to place each one. Project engineers sunk these deep into the valley bedrock and covered them with reinforced concrete.

The deck was made from hollow steel and was prefabricated in sections at the Eiffel factory at Alsace in eastern France - yes, that Eiffel.

Above: Each tower was placed using GPS. Image courtesy of Foster + Partners.

Each section was then floated down the Rhine, to the Mediterranean, to the French coast, and then driven by road to the construction site.

The deck was then slid across the completed towers using enormous hydraulics that pushed them across the valley a little bit every day. They were launched simultaneously from both sides over temporary structural supports.

During this time the weather had to be closely monitored, strong winds could damage the deck before it reached the next supporting tower as each “launching” operation would take up to three days.

Even with the GPS technology it wasn’t a certainty that the deck would meet in the middle, the piers would line up, or that the colour was the correct one.

“Whether it's a bridge or whether it's a building, we now have more sophisticated means of visualisations. I mean, I've just come from a design session and I'm wearing these goggles and I can see everything three dimensionally. But the truth is, until you actually see the real thing, you really don't know.”

The day the two halves were due to meet was a nervewracking one for everyone involved.

A champagne bottle was placed between the deck and smashed in celebration when they met. In the end it was with millimetre precision.

An icon completed

It was only now the architecture and engineering teams could view their bridge and see if it was a success.

“The relief. I can't. I can't tell you.

“It's only when you come on the approach road.

“Then wonderfully, you realise it was the right decision.”

From the beginning Lord Foster did not want the road to be a simple straight line. He wanted it to curve over the valley, so that as you drove across it you could get a true sense of the bridge’s scale.

“It's on a 20 kilometre arc. And when you drive over that bridge and it unfolds, so you're seeing the alignment, you're seeing the pillars disappearing in perspective.

“I think without question, it's a more beautiful expression than literally a one liner. There is an extraordinary subtlety.

Above: The bridge rising above Millau. Image courtesy of Nigel Young / Foster + Partners.

“The sides are transparent and it's very, very difficult to find a bridge where you can drive over and you can actually see, you feel you’re on that shelf. So you've got all the safety, all the protection. But you can see across. So it's the closest you can get to fly to when that is literally above the clouds.”

Far from destroying the economy of Millau, the bridge became an instant icon and tourist attraction in its own right. Visitors come far and wide to see the bridge and the village, but now there is no congestion.

“When I was last there, somebody came up to me and said something along the lines of, When you were doing this project, I protested.

“This individual said, I just want to tell you we were wrong. You know, we just love this building and everything that it's done for the community.

“I would like to think that the response, the way in which it's almost a gravitational magnetic pull where people want to come see it from a distance, view it experience to drive. I think in a way that's a kind of vindication of the all the hard work.

“When you see it's like the tip of the iceberg. What you don't see is all the stages, all the long, hard work, long hours that's gone into that process.”

The road opened up this area of France and changed the map of Europe. Within three years the bridge paid for itself.

The detour also saves around 40,000 tons of CO2 emissions from heavy goods vehicles alone, the equivalent of 40,000 trees absorbing emissions over 40 years.

The viaduct illustrates, perhaps more than any other, the importance of good design and of the power of involving architects in infrastructure projects. That architects and engineers can achieve remarkable things when working in harmony.

“It's really important to break down the barriers between the different parties because in the end, all of these things are in the public domain. And in my experience, the more views, the better.”

Because of its beauty the bridge does not detract from the landscape around it, it only adds to it, and elevates it to new heights.

“When you look at it. It's not a work of architecture, not a work of engineering. It's a work of infrastructure.

“It transcends the function of just getting from one side of a river to the other.

“It starts to take on a symbolic quality. It becomes emblematic of the place.

“It's unique. You can't compare it with anything else. I mean, you can talk about buildings and you can say this building or that building, but there's only one Millau Viaduct.

“Twenty years later it is still just as breathtaking.”

This video and article contain paid promotion for Odoo.

Video narrated and hosted by Fred Mills. Additional footage and images courtesy of Foster + Partners.

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