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Before you read this, you might like to look at a presentation of photographs depicting the stages of construction. There are some very good pictures. Pick on this link and then save the file to your computer. When loaded, pick the open option. Pick on each picture to advance the presentation. Here is another. Save it to your computer first, it is much the quicker option.
the Millau Viaduct,
got built as he wanted it, only to be overshadowed by architect Lord Norman Foster. Andrew Mylius met him in Paris for the engineer’s angle. The following report by Andrew was published in The New Civil Engineer 10 February 2005. Michel Virlogeux’s business card says a lot about how he sees engineering - or at least his role as a designer. It declares him as an “engineering consultant and ‘concepteur’ for works of art”. Immodest the proclamation may seem, but with design of the dazzling Millau Viaduct (NCE 16/30 December 2004) and Pont de Normandie (NCE 12 November 1992) among the 100 or more bridges on his curriculum vitae, it would be hard to dispute. In the flesh, though, this dapper 58 year old is anything but assuming.
Ensconced in a shabby room loaned out
to him by cable stay specialist Freyssinet in the industrial southern suburbs of
Paris, Virlogeux explains in rapid-fire English and with a good deal of
gesticulation that he sees himself in an 18th century tradition of French
engineering. Design offices are having aesthetic creativity squeezed out of them by increasingly slender fees, he believes. “They don't have enough time to work, not enough money to develop ideas - and in the long term it means we’re losing the best engineering students.”
He also lays much blame for the loss
of art in engineering on the use of computers. They dehumanise the design
process, he argues. And their ability to crunch the numbers involved in any
problem, however bizarre or inelegant, actually stops engineers from asking
fundamental questions about form and force.
Virlogeux offers the maxim used by the
western world’s first known engineer, Vitruvius, as a guiding principle.
In seeing the Millau Viaduct through
from conception to completion, Virlogeux has set out to exemplify the synthesis
of engineering with art. He claims to have been unruffled by the widespread
misapprehension, even in France, that UK architect Sir Norman Foster designed
the leggy, multi-span cable stay wonder. And lately the balance of attention
has swung heavily towards Virlogeux, to the extent that the half to full day a
week he is giving up to radio, TV and magazine interviews is becoming a cause
for concern.
Even so, he admits he has been
overshadowed by a man who played second fiddle throughout the whole design and
construction process.
Yet Virlogeux is emphatic: He could
not have made the Millau Viaduct the triumph it is without Foster. He backtracks to the inception of the Millau project in 1988, when as head of state transport agency SETRA’s bridges department he started looking for an alignment for this section of the Paris -Barcelona auto-route. Virlogeux decided to cross the valley by descending to the River Tarn from the north. He would leap it with a bridge with a fairly impressive 700m span - the length was important “to limit the height of the piers”. The road would then continue up the steeper southern side of the valley on viaduct before entering a tunnel through the valley wall to reach the plateau above. “Though it was not beautiful it seemed to me the only practical way. But as soon as the idea was fixed, a road engineer asked: ‘Why do we have to go down [into the valley]? Why don't we go straight across on a viaduct?’ It was absolutely clear, that was the solution,” Thrilled by his colleague’s radical alternative, Virlogeux sketched various multi-span cable stay options and within a few months selected a seven pier design as his favourite. His department worked up 20 or so alternative designs, “some of which were absolutely ugly, absolutely stupid”, to make sure there were no better ideas “and to prove that the multi-span cable stay viaduct was the best”. The list was winnowed down to seven. But Virlogeux’s plans were to be hijacked. Design of the Millau Viaduct coincided with construction of his first really big bridge,
the
Pont de Normandie,
and
with a change at the head of SETRA: The director through the 1980’s, an
engineer “who was interested in everything technical”, was replaced by a
politician.
Those fears were realised with
Virlogeux’s unwitting help. Seven designs, including Virlogeux’s multi-span cable stay brainwave and two other SETRA options, were short listed. But the upbeat public announcement was accompanied by a blow. SETRA’s director declared that the internal design office, Virlogeux’s team, would be taking the project no further. The project would be let to external engineer-architect teams. With 20 years at SETRA, Virlogeux was torn. However, “I had not developed such a beautiful solution to hand it over to somebody else. I believed it to be the best design, and I wanted to get it built.” He prepared to jump from SETRA and set up on his own to take his design forward. After that, the partnership with Foster came naturally, Virlogeux says. “Foster had been selected [as one of the seven short listed designers] because he liked this [Virlogeux’s] SETRA solution the best - he was convinced of the solution. He made some drawings which we could not build - the columns and deck were too slender - but were expressing something very simple, straight, light, transparent. This was exactly what I wanted.” They joined forces.
Their working relationship followed a
pattern tried and tested on most of the projects he has undertaken.
The tables then turn. Virlogeux asks
his architects to sculpt his structures so they best express the forces at play.
At no time, however, did Foster’s
input infringe on structural good sense, though. “Foster understands
structures. There’s big fashion for architects to do crazy things, and engineers
feel obliged to make them work, or to do big and striking things themselves to
compete with architects. Some are taking risks. One of the great things about
Foster was he did not try to push us in a dangerous direction technically.”
Foster's contribution to Millau is
measured by its invisibility rather than by any obvious stamp of authorship,
Virlogeux says. The bridge’s efficiency is laid bare through looking very
simple.
The architect’s touch can be seen in
the way the columns rise apparently straight from the ground. Foster insisted
that the viaduct’s colossal pile caps be invisible. Finding the ideal form for
the columns themselves involved an evolution through 40 scale models.
Millau’s box girder deck flows seamlessly into the hillside at either end.
Foster also eliminated intermediate
piers from the first spans of the viaduct.
On the Pont de Normandie Virlogeux
applied a principle successfully tried on a small cable stay bridge he designed
in the 1980s. Intermediate backspan piers were used to provide rigidity,
acting as additional anchor points and so stiffening the main span.
If any doubt lingers about the
engineer’s feelings for the architect, Virlogeux dispels it. NEW CIVIL ENGINEER 10 FEBRUARY 2005
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Last Edited : 22 August 2008 00:03:26 |