The role of new technologies and new theoretical instruments
by Salvatore Di Pasquale
It is important
to make clear what meaning the term “structure” has been
acquiring over time. It originally comes from the Latin word struhere
that precisely means “to build”. We may find an exhaustive
answer if we consider the term “structure” in its abstract
meaning. The latter is reported in all vocabularies where it is defined
as the relation between various parts and, in particular, between various
elements of a building that have a static function. Viollet le Duc’s
vivid intelligence didn’t fail to observe that large stone buildings
reveal epochs that can be characterized by the relevance they assign
to the structural function and the way it is translated into clearly
identifiable symbols. Viollet le Duc understood that prior to any rigorous
structural analysis of a building it is indispensable to identify the
pressure curve linking the loads that help to find the best solution.
We shouldn’t forget though that Viollet’s education wasn’t
the least connected with the language of mathematics. And we may therefore
ask ourselves what did he possibly see to come to such an undoubtedly
true and striking conclusion: not the forces with which the pressure
curve is built since they are a mental construction, but rather the
effects they produce or say, the fractures that happen to be clearly
visible. The idea that such an analysis could be carried out even for
a structure made of material rather resistant to tensile stress, almost
unable to support this kind of efforts, was soon developed. At the end
of the 19th century, C.A. Castigliano made a first step in this direction
when he proposed the analysis of railway bridges built with dry stone
ashlars. The methodology, though undoubtedly valuable, failed to take
into account the stress to diminish tension regime. Although the way
was almost defined by then, the trend of theoretical and experimental
researches to focus on steel and reinforced concrete put immediately
an end to the newly opened chapter on the calculation of stone building.
Today, things are completely different. On the one hand, it is possible
to use new instruments of structural calculation that inform us on the
state of stress in any structure, whatever the shape. On the other hand,
innovative materials and techniques - acknowledgeable with the abbreviation
FRP (Fiber Reinforced Polimer) - offer many opportunities for the future.
