Widmann A.G., starting in the mid-
1920s.
In 1937, he began work developing
a prestressing system and designed
and built his first bridge. Then after
45
World War II, his major prestressing
work began, which he reported on in
His work since that time was so
broad and varied that it defies simple
characterization, except to say that
more than anyone else, perhaps, Fin-
sterwalder showed that prestressed
concrete can be a safe, economical,
and elegant solution to almost any
major structural problem that exists in
the modern world.
In a 1970 interview, Finsterwalder
mentioned that his favorite bridge was
the Mangfall Bridge, under design just
at the time of the Berkeley Confer-
ence. With this bridge, as in other pro-
jects, Finsterwalder sought to show
that prestressed concrete could com-
pete directly with structural steel, not
only in cost, but also in reducing the
structure’s depth.
In the Mangfall Bridge, built by his
cantilever method but made with open
truss-like walls, his idea was to dupli-
cate the girder depth of the steel
bridge built in the late 1930s and de-
stroyed in World War II. Not only did
he succeed technically, but in design-
ing a two-level bridge (see Fig. 8), he
provided the pedestrian with one of
the most spectacular crossings since
the Brooklyn Bridge in New York.
Like Freyssinet and Magnel, Finster-
walder came to believe in prestressing
after having a long experience in rein-
forced concrete construction and espe-
cially, like Freyssinet, in arch and thin
shell structures. Finsterwalder learned
mathematics while in a French prison
camp during World War I.
After the war, he put that knowl-
edge to good use in shell theory which
served as the basis for the many out-
standing thin shell concrete structures
designed and built by Dyckerhoff and
Finsterwalder had the idea of pro-
viding a prestressed concrete alterna-
tive to every steel bridge design in-
cluding those with very long spans
which had previously been the sole
province of suspension bridges. His
stress ribbon bridge, for example, con-
ceived at about the same time as the
Mangfall design, carried prestressed
concrete far beyond its previous lim-
its. Later, he made a design for the
Bosporus Bridge which would have
had a free span of 1500 ft (454 m).
47