STRUCTURAL GLASS FACADES - USC School of Architecture

2.3.3.2 Rods
Design innovations are often the result
from the borrowing of a developed
material or process from a related or
unrelated industry, and applying the old
technology to a new problem. Highstrength
tension rods were developed
Table 2-2 Hayden Planetarium, New York; Polshek
Partnership architect, glass fixing by TriPyramid
Structures (TriPyramid 2005).
for use on racing yachts. Tim Eliason
had founded Navtec, a company
providing rigging systems to the
yachting industry, and had played a key role in the development of rod rigging systems. He
got the opportunity to transfer some of the technology when invited to participate on the
Pyramid at the Louvre. Subsequently, Eliason started TriPyramid Structures to pursue
opportunities for cable and rod rigging systems in the building arts. TriPyramid has been one
of the leading innovators in the evolution of structural glass facades, producing some of the
finest design and fabrication work the technology has produced.
The end terminations for rods present a different problem than that presented by cables,
which can be swaged or soldered, techniques that will not work at all on rods. Rods can be
threaded at the ends to receive threaded end fittings. Alternately, threaded fittings can be
placed on to the rod, and the end of the rod upset by a process called cold-heading,
whereby the rod end is compressed in a hydraulic press so that it mushrooms. The end
fitting is thus affixed to the rod.
The design of these connections is a subtle art. There are a number of factors to balance,
including the intent to conceal the threads in the installed work. The fittings must have
enough tolerance build in to the design to accommodate field conditions of the installed
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