French bridge master: Michel Virlogeux

Virlogeux addressed a packed room of architects and engineers, revealing the design story and construction process behind Millau, the world's tallest bridge. The exhibition, which runs until 20th September, showcases a number of contemporary bridges of all scales with models, images and commentary from leading designers.

KA: You're not a fan of computers. Why is that?
MV: I don't use any computer at all – just a little calculator, just like one you would use for college. Of course, there is computer work done but you see, designing a bridge is something that is done by steps. We begin with a concept, in fact concepts, and we then try to select the best. The designer is organising the material to take the flow of forces - you can make very simple analysis and you can do that on a very small calculator. Of course, after that you have different levels of design. There is preliminary design to detailed design and at all stages there is computation -  which becomes more and more accurate - but at the beginning there is no computation unless it is a very, very sophisticated structure.

Virlogeux at the opening of the Span exhibition (photo Agnese Sanvito)

Do you feel then that design at the early stage is at risk of being driven by the computer?
It is my opinion yes. I think that it is a mistake to go too far and too quickly with the computer. For me it is much better – and I am not alone you know – it is much better to make some drawings which are very simple, even out of scale (because we can add scale later) and you can go from that to detail. 
And what is very important when you are designing is to be extremely rigorous… sometimes, when you develop a design you discover that there is something not working in the concept. You must not solve the problem by editing, you have to re-concept, globally, the structure, so that at the end you have something that is very pure. 
We are in a very controversial period. We have different types of structure. You have structures that are coming from fantasy, imagination and those from an artistic concept. This is not the way I like. I like structures for which the architecture is completely guided by the structural forces and the Millau Viaduct is a good example of that. 

Millau viaduct - architecture guided by structural forces

The architect Lord Foster never tries to pass from this idea to another one. It was great to work with him and his team because it was our goal to find a solution that was elegant, beautiful and totally in the structural concept. So, may I say, he has modestly accepted to follow the structure but that is not to say he did nothing– that would not be true at all. It is absolutely clear that without Foster the bridge would not have been as elegant and he had some ideas completely different from that, for example he wanted the piers to emerge from the ground so that we don't see the pile caps.
The piers really now, when they are finished (the surroundings have been re-shaped) simply appear out of the ground. He [Foster] wanted also for the bridge to give the impression of penetrating the hill at each side. That was a nightmare because, although it has been very easy to design the abutment (we have made a very narrow supporting element and on top something that takes the shape of the bridge to create the impression of penetration) the nightmare came with the safety barriers, with the windscreens, because they had to adapt the expansion joint. You know when you have an expansion joint of one metre, you can imagine that adding a safety barrier which is able to resist that is a nightmare.  For classical abutments it is not a problem because we have a massive abutment…
 
Chris Wilkinson of Wilkinson Eyre has said that he would like to see more bridges over the River Thames because bridges have the ability to regenerate areas and indeed, your Millau viaduct has regenerated a whole area. How do you think bridges manage to do that? What is special about bridges?
They are big structures. And they are very symbolic. If they are poorly designed of course they can be a disaster so we must be very careful… I will quote something from an architect who worked on the Millau project: 'working with the scale of the Millau viaduct, we are working with geography' and it is also something that Foster said also.

A bridge like the Millau viaduct can play a major role in regeneration

Foster came onto the project and he had looked at it and developed it very well. And he had a word – you see, that is one of the advantages of architects, they find good words - this was already the idea but he said 'We are not crossing the Tarn Valley, we are flying from one plateau to the other plateau.' This is the same image… that scale. You know, I am also the designer of the Normandy bridge which is the same. The landscape is not the same today. I feel lucky to have designed two bridges of this scale.
 
Would you like to design a bridge for the River Thames? 
With pleasure, yes of course! It is a drawing by someone somewhere. You see there is a competition each time, each new project. You are losing more frequently than you win. We have lots of competitions with Lord Foster.
 
What are you currently working on? 
Well, firstly you must know that this is very long term work. The Normandy bridge took 19 years, for Millau it was 17. So of course it is not full time – a project stops for a year or so and then comes back, and sometimes there are big problems…

Virlogeux' Normandy bridge took 19 years from start to finish

So today we are finishing a mobile bridge at Rouen – a very big bridge, a lift bridge, with a lifting span of about 20 metres. And it is almost finished. I have designed a curved cable-stayed bridge in French Brittany – a very striking project with a big span of 1,292m. I am also beginning the design – we won the competition, a design and build competition – for a mobile bridge in Bordeaux – practically the same span, 1 m less but in my opinion more beautiful.

Virlogeux' lift bridge in Rouen under construction

And we have a project in New York but this is very difficult because in America they are too much concerned about cost. Sometime you have a suitable project and you have a value engineer coming and he says 'oh, you can reduce cost there and reduce cost there' and then it is not so beautiful.
 
Have you ever worked in the UK? 
No, I have never designed a bridge in the UK. I have worked slightly – I tried to take part in the competition for the new Forth Bridge – it was eight years ago? – but it was cancelled. The competition was to double the Queensferry Bridge and I think it is now been re-launched but no British team called for me! 
 
And you always work with an architect? 
Yes. You know I have been working for a long time. Since 1976 I have always worked with an architect. We do have to be careful with public money. We are not supposed to make our reputation with public money. We have to make something elegant but we have to remain reasonable.
But at the same time, I like working with architects – I think we are very much concerned with the issues of safety and strength but sometimes we are not considering all of the product. Take for example the idea of Foster's to have the piers emerging from the ground. It is not something we considered really, for me it was a minor problem. Of course, I am not reducing architecture to that but they came with another eye and with a different approach and it is clear that when, at the end of the conceptual stage, the architect and the engineer are really both satisfied it is a good sign. 
For another example, we worked with a French architect Charles Lavigne who sadly is no longer here. We were working on a competition for a small bridge at Limoge. We were working on an arch bridge. I wanted to design an arched bridge because in this city all the bridges from the Middle Ages are arches -  all of them. So we made sketches and we improved the sketches and suddenly, in one of our meetings Charles said: 'We are out of touch. The city of Limoge wants us to incorporate the river banks of the city. The bridge is not incorporating the river banks of the city.' I found a solution but I would never have thought of it in that way. And immediately Charles made sketches and it was wonderful.

Through worling with architect Charles Lavigne, Virlogeux found a way to incorporate the river banks in the Limoges bridge

What we have done, we have done with Charles again – another arch bridge. So we were designing a big arch, 200m span in Brittany. And the local authorities said: 'OK, each side there is a route for pedestrians and joggers. It would be good to make a path for them.' So I imagined to put the pedestrians on the arch itself and so we worked with the architect to make something elegant.
So for this bridge in Limoge I wanted to pass the pedestrians over the arch but we did not have enough space and so we put them through the bridge. We widened the bridge and they come through, walk on the side walk and come through. I should have never thought of that. We won the competition because we were the single ones to think of that. So I think really, it is good to work with architects on condition that the architect does not want to make something completely crazy. Honestly, I have withdrawn from competition teams because the architect wants that and I say: 'OK, do it but without me.'

Visitors to the SPAN exhibition (photo Agnese Sanvito). The exhibition, which runs until 20th September, showcases a number of contemporary bridges of all scales with models, images and commentary from leading designers. For details of the exhibition, click here

 
  
  
 

 

 

 

 

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