STRUCTURAL GLASS FACADES - USC School of Architecture

from the yachting industry and used initially on the Glass Walls and the Pyramid at the
Louvre structures discussed previously).
As any builder knows, there is risk in doing anything he has not done before, and when the
doing involves something that no one has ever done before, the risk escalates a rough order
of magnitude. The best way to mitigate this risk is to incorporate a rigorous and
comprehensive mockup and testing program as part of the project execution. This was
precisely the strategy employed by Paxton, the designer-gardener-builder, in the execution
of the Crystal Palace. Fabricated components were test-assembled to assure fit-up in the
filed. Iron was a relatively new material, and no reliable means of calculating component
capacity existed at the time. Lacking sophisticated testing equipment, iron assemblies were
field-tested by regiments of soldiers marching in cadence over a stepped testing fixture
supported by the iron assemblies prior to installation in the structure. The successful
completion of this nearly 1 million square foot structure in a mere 6 months time had much to
do with the adoption of these strategies.
Nonetheless, such measures add time and cost to project execution. These measures,
however, become increasingly unnecessary as the behavior of the structures and capacity of
materials are proven out over a series of completed projects. Innovators and early adopters
of the structural glass façade technology have now born much of the development costs.
The UBS Tower in Chicago features a cable net enclosure at the ground level public area of
the building, the first such structure to be designed in the US (Sarkisian et. al. 2007).
Concern among the design and developer teams regarding the use of such new and
unfamiliar technology prompted them to require full-scale mockup testing by the design/build
contractor. The test was useful in demonstrating predictable deflection behavior to the large
group gathered to witness the test at a curtain wall testing facility in Florida, and to validating
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