This 1976 paper ended with a brief
reference to the Swiss bridge designer,
Christian Menn, and to his spectacular
Ganter Bridge then in design and since
completed in 1980. However, within
that time period of the essay, Menn
had completed already a series of
bridges using prestressed concrete,
some of which are now recognized as
the most elegant structures of their
type, especially the Tamins-Reichenau
deck-stiffened arch of 1962 and the
Felsenau segmental cantilever girder
of 1974 (see Figs. 12 and 13).
In both cases, Menn freely used par-
tial prestressing as a means for refin-
ing his design. This leads me to the
very fine discussion of my 1976 paper
by the distinguished Austrian-British
pioneer of prestressed concrete, Paul
Abeles. Abeles emphasized the sig-
51
nificance of partial prestressing and of
the role played by Gustave Magnel
and Pierre Lardy (1903-1958) in
amending Freyssinet’s insistence on
the clear separation of prestressed con-
crete from reinforced concrete.
It is now becoming clear that the
proper term, structural concrete, will
in the future be used to describe a de-
sign field that uses both mild steel re-
inforcement and prestressing steel in
varying combinations.
The idea of structural concrete led
Menn to designs now recognized as of
the highest quality yet achieved in
concrete. His teacher was Lardy in
Zurich, and another of Lardy’s stu-
dents, Heinz Isler, has created radi-
cally new roof forms in thin shell con-
crete construction, where the use of
prestressing has been essential (see
Fig. 14).
In 1999, I returned to Ghent, where
I had studied under Gustave Magnel
48 years earlier. While I was there, I
presented a paper on Magnel (and
Anton Tedesko) and four years later
52
organized an art museum exhibition
on the works of Isler, Menn, and
Lardy, along with the works of other
Zurich educated engineers including
Wilhelm Ritter, Robert Maillart, and
Othman Ammann.
In retrospect, it was Magnel that had
set me on my career and to him I owe
its beginning; this inspiration has led
to the discovery of structural engineer-
ing as a field that has created some of
the greatest symbols of the 20th cen-
tury and holds even greater potential
for this new century.