Cables, Rods, Castings, and Machined Components
In addition to the glass and structural systems that comprise structural glass facade technology are the components that in turn comprise these systems components quite unlike those typically used in exterior wall systems.
The use of tensile elements in the form of steel cables and rods is a primary design strategy to dematerialize the structure and enhance the transparency of a facade design. Compression elements are frequently minimized or eliminated, and where present are crafted from cast and machined components in an elegant expression of exposed structure. The fittings and components that tie these structural members together are similarly crafted.
Here an entirely different set of material and process considerations come into play. The Enclos design team has mastered these materials and processes as a necessary prerequisite to their appropriate application in component design. We can develop and provide custom designs of remarkable diversity in response to your particular project needs. Where appropriate, we can also source off-the-shelf components from a variety of suppliers, all carefully qualified to Enclos Corp standards and subject to our uncompromising quality assurance program. All this, from concept design through installation, as part of a single-source package from the largest national specialist in structural glass facade technology.
Cables
Bridge builder and engineer John A. Roebling first manufactured wire rope in America in the 1840’s. These materials ultimately found their way into the vernacular of architecture through such stunning works as Mathew Nowicki’s Dorton Arena of 1952 and the Ingalls Rink at Yale University of 1958 designed by Eero Saarinen. Structural glass facade technology has embraced these tensile materials as a means to minimize the structural profile of the support system.
Wire rope composition, material type, finish, and end terminations are all important considerations in specifying these materials, which are available from a relatively limited number of manufacturers and specialty fabricators.
Enclos Corp has put many of these manufacturers through its rigorous qualification process, resulting in several exceptional vendor/partners that have successfully provided materials on various structural glass facade projects that we have completed in recent years.
Casting
Casting is an ancient process with a longtime role in the construction industry, including the naming of a “cast-iron architecture” during the industrial revolution resulting from a dramatic increase in the availability of low cost cast materials. Castings were much later used to spectacular affect in the gerberettes and other components for the Center Pompidou by architects Rogers and Piano. The casting of structural components however demands a high level expertise in both the design and fabrication process. Cast nodes for the space frame structure on the Javits Convention Center in New York were famously discovered during construction to contain cracks, requiring the disassembly of nearly half the structure and a project delay of nearly two years. An intimate knowledge of the materials and processes of casting is critical to the development and implementation of a custom cast structural component. Among components appropriate for casting are spiders and glass-fixing devices, spacer struts and anchor assemblies. Various options for material and finish must be considered depending upon component design application.
Rods
The use of steel rods as a substitute for cable in the design of structural glass facades was a practice borrowed from the yacht racing industry, and popularized in the Louvre Pyramid designed by IM Pei. The rods are most commonly fabricated from ASTM A316 stainless steel because of the material’s combination of strength and corrosion resistance. In high load applications or when super thin profiles are desired, there are other higher strength stainless options. The rod terminations are often custom designed and can be quite refined, with the intent of minimizing or eliminating any exposed threads, turnbuckle or other tensioning mechanism. Rod fabrication typically involves slipping the end fittings over the rod and upsetting the rod ends through a process called cold-heading. Alternately, equally elegant threaded fittings have also been developed. Depending upon the design of the structure, cable systems can have significant advantages over rod systems, particularly with respect to cost. However, some feel that the refined appearance of a rod system is worth a premium cost
Machined Components
In many respects, structural glass facade technology is more closely akin to the automotive industry than it is to conventional construction. Spider fittings are about as far from the brick as a building component can be. Structural glass facades are highly engineered structures built to very high tolerances. There is also an important visual aspect to the components because of their use in exposed structural systems. Despite a widespread pursuit of facade transparency, many designers choose to express this exposed structure in dramatic fashion, sometimes even at the expense of ultimate transparency. These factors and considerations make the use of machined components a frequent and effective choice. We design custom components or specify off-the-shelf parts as appropriate, and source both from our network of vendor/partners.
