Pont de Normandie - Pushing the Limits: New Adventures in Engineering - page 35

As is not unusual with novel engineering projects, an independent review panel was established
to assess the safety and practicality of the structure and to recommend changes in the design.
However, in his 1993 report on the design and construction of the Pont de Normandie, Virlogeux
made clear his control over the project by writing that the panel's recommendations were “con-
sidered” rather than adopted. The fact that the chief engineer's extensive report was published while
the bridge was still under construction was noted by other engineers to be unusually welcome, for
such reports typically follow by years the completion of a project, by which time there is naturally
less interest in them. The report's publication itself was thus a further indication of Virlogeux's high
degree of confidence in himself and in what could fairly be called his bridge.
Although Virlogeux did not diminish the contributions of the members of his design team or the
benefits gained from the reports of the bridge projects of other engineers, it was clearly his person-
ality that dominated the Normandie operation. Colleagues, coworkers, and associates over the years
remarked, some more euphemistically than others, that in their dealings with Virlogeux they found
him to be “very direct” and, in fact, sometimes “to speak his mind too readily.” He was recalled by
engineers at SETRA to be an “exciting, stimulating person, who is nevertheless difficult and dog-
matic at times,” and to be one who “doesn't listen very well.” According to the German bridge de-
signer Jörg Schlaich, a member of the review panel, Virlogeux was “happy to have what he thinks
confirmed, but not to have people come up with alternative proposals.” Although this clearly made
him difficult to deal with, at the same time “this is his strength.” Schlaich further understood that
with bridge building generally, “If you listen to too many people, you will never come to the point.
This self-confidence is what you need” to design a world-record bridge. In this regard, Virlogeux is
in the tradition of great bridge builders such as John Roebling.
The site of the Pont de Normandie is a major shipping channel, and introducing piers into the
water not only would have posed obstacles to oceangoing vessels but also would have promoted the
accumulation of sand, a further obstacle to shipping. This led Virlogeux to look to piers in excess
of eight hundred meters apart, which at the time put the projected central span well beyond cable-
stayed experience and into the range of suspension bridges, such as the one upstream at Tancarville.
Thus, a suspension bridge would have been the expected form to adopt at Le Havre. However, Vir-
logeux found that, although the pylons or towers of a cable-stayed design would be more expensive
because of their additional height, stay cables could be installed at less cost than suspension cables,
and there would be a significant savings in not having to construct massive anchorages. On the other
hand, the cable-stayed solution did entail construction in a realm that was unknown. To counter this
uncertainty, Virlogeux did what engineers before him have long done—that is, he pointed out that
in the past great bridges had successfully been built with spans that went well beyond experience. In
1931, for example, Othmar Ammann's George Washington Bridge was completed with a 3,500-foot
suspended span, which nearly doubled the previous record 1,850-foot span of Detroit's Ambassador
Bridge.
Because Virlogeux knew that he was designing in a new realm, he looked carefully at suspension-
bridge technology for guidance. In particular, he studied the deck designs of two British suspension
bridges, the Severn, with a span of almost one thousand meters, and the Humber, with a span in
excess of 1,400 meters, then the longest in the world. These streamlined hollow box-girder decks
were developed in the course of conducting wind-tunnel studies after the Tacoma Narrows failure