STRUCTURAL GLASS FACADES - USC School of Architecture

eing used as a structural element of the enclosure as a stressed skin. These innovators
were far ahead of their time in using glass as a structural element, even before the advent of
glass-strengthening techniques. (Wigginton 1996, pp.34-37)
While the building form represented by the conservatory structures quickly transcended its
early botanical applications to become an important public structure type, perhaps as best
represented by the Crystal Palace, there was no real integration of this building form with the
conventional architecture of the time. (There are certain relevant exceptions, primarily
involving the glass roofs of train halls and shopping arcades such as Pennsylvania Station,
New York, 1905-10, McKim, Mead and White, and the Galleria Vittorio Emmanuele II, Milan,
1865-7, Giuseppe Mengone, but these represent unique building forms themselves that
typically interface rather than integrate, with the adjacent architecture.) The great
conservatories were all free-standing, autonomous buildings. Certainly they inspired, as they
continue to inspire new generations of designers even today. Equally certain they fueled a
continuing increase in the desire for and use of glass in architecture. (Wigginton 1996,
pp.47-48)
Meanwhile, in the great cities of Europe and America, density and land values were creating
pressure to build upwards, pushing the limits of the predominantly masonry building
practices of the time. By the end of the 19 th century, a Chicago engineer named William
Jenney had devised a method of steel framing and thus gave birth to the technology of highrise
buildings. Exterior walls became functionally different in a quite significant way; as with
the earlier iron framing systems used in the conservatory structures, they were no longer
load bearing, carrying only their own weight over a single story span. They need no longer
be masonry (although masonry remained the predominant wall material for years to come);
in fact masonry was an inappropriate material for most of these new applications because it
was unnecessarily heavy. (AAMA n.d.)
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