Civil Engineering Reference
In-Depth Information
shaping appropriate both to providing efficient load resistance and shedding of
precipitation. Membrane covers may in turn be categorized as ones that are open-
sided or that enclose space. Open sided structures are perhaps the most common
application of tensioned fabric, as they take advantage of the material's ability to
provide protection from sun and precipitation, while maintaining almost unlimited
ventilation and visual transparency to the exterior. Their application is limited by
their inability to control temperature and other environmental factors, or to provide
security. Common open structure applications include stadium grandstand covers
(Riyadh, Figure 1-9 and Seoul, Figure 1-19), amphitheaters (Woodlands, Figure 1-10;
Chene Park, Figure 1-11; and Pier Six, Figure 1-13), and entrance canopies (Hampton
Roads, Figure 1-22).
Enclosed structures provide the opportunity to create complete interior climate
control. The energy efficiency of such structures (discussed in Section 8.3) is highly
dependent on local climate, fabric optical properties, and whether multiple fabric
layers, insulation, or other special measures are used. Applications for enclosed
structures can range from greenhouses using transparent film membranes to
convention or theater facilities that employ opaque fabric to provide complete interior
lighting control. Examples include recreation facilities (La Verne College Student
Activities Center, Figure 1-7), exhibition buildings (the U.S. Pavilion at the Osaka
World Fair, Figure 1-5), airport terminals (Denver Airport, Figure 1-14), and
stadiums (Georgia Dome, Figure 1-16).
A few designs have taken advantage of the light weight and flexibility of fabric
membranes to provide “convertible” structures where the fabric membrane can be
opened or even removed, thereby realizing some of the advantages of both enclosed
and open structures. Sometimes the membrane slides along its supporting cables to
open and close the roof, as is the case with the Commerzbank Arena (Figure 1-26)
and the Kufstein Canopy (Figure 1-28). In other convertible structures, the membrane
is supported by a rigid structure which moves or articulates to convert from closed to
open form. This approach avoids membrane stress or strain associated with the
conversion, and the associated risks of fabric damage. Finally, some convertible
structures employ cables and framing members that fold or disassemble along with
the membrane. These designs require careful attention to erection and disassembly
mechanisms and to material choice, in order to avoid damage during deployment. At
the Carlos Moseley Music Pavilion (Figure 1-12), for example, vinyl-coated polyester
fabric and Kevlar cables were used because of their ability to accommodate the tight
bends associated with packaging the structure between deployments.
8.1.3 Attached Membranes
Attached membranes are covers which are supported at least in part by adjoining
“hard” building construction. Attached membranes may serve several important
architectural functions. Perhaps most important, they provide a “soft” transition
between interior and exterior that is characterized by protection from precipitation,
transparency to the exterior areas adjoining the building, and lighting levels that are
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