“When by chance, they approached
this domain, the absence of a directing
idea prevented the drawing of conclu-
sions that were of any practical conse-
quence.”
This directing idea, for Freyssinet,
was, in general, that simplification of
forms and economy of means so char-
acteristic of his artisan heritage; or as
he said once to a group of young engi-
neers:
24
“I loved this art of building which I
conceived in the same way as my arti-
san ancestors, as a means of reducing
to the extreme, the human toil neces-
sary to attain a useful goal. . . from the
bridges of Septfonds and Le Veurdre
to those of the Marne and Caracas”
(two of his best-known post-World
War II bridge projects). Fig. 4 shows
the Luzancy Bridge, one of several
prestressed concrete bridges Freyssinet
built across the Marne River.
More specifically, this passion he
felt for prestressing went on to define
prestressed concrete as an entirely new
material with the widest possible ap-
plication. For Freyssinet, “the fields of
prestressed concrete and reinforced
concrete have no common frontier.”
Either a structure is fully prestressed
or it is not to be called prestressed
concrete.
We do not need to accept that rigid
definition today to recognize how es-
sential it apparently was to Freyssinet
to have this idea of prestressing as a
new material in order to direct his en-
ergies into practical applications. It
was to be crack free, a structure in
which the elongation of the high
strength steel was to be independent of
the strain in the concrete.
One has only to read his writings to
realize that Freyssinet was more an
advocate than a teacher, more an origi-
nator of ideas than one who explains
them to others. In his writings, he can
even now communicate clearly to us
his passion but not so well his techni-
cal concepts.
It took another sort of person to
make clear the simplicity of prestress-
ing and especially to bring it to the
United States. Without question, the
most influential engineer to do this
was Gustave Magnel.