For applications where hanging loads are desired for implementing fire suppression systems, catwalks, overhead cranes, mezzanines, or other significant and heavy features on the frames, those loads can be factored into the original rendering. Using finite element analysis, the size and thickness of each individual beam can be manufactured to match the building’s load factors. This precision makes it simple to strengthen the frame exactly – and only – where necessary, rather than over-engineering an entire structure at a higher cost. I-beam design is also tailor-made to combat external loads from forces of nature like wind and snow. Engineers can slope the roof and shape the sidewalls as necessary to withstand heavy snow loads, not to men- tion add ice breakers, gutters or other external roof features. For areas frequented by hurricane activity, buildings can be designed with wind ratings up to 240 miles per hour. Internal Use Factors It’s common for the structural steel frame of a fabric structure to remain exposed and visible within the building interior. Applications such as wastewater treatment, composting, fertilizer housing, and salt storage all create the added challenge of needing to protect the building frame from the damaging effects of corrosion. When web truss was the industry standard, it wasn’t even possible to always know if the frame had been compromised. The hollow-tube frames could corrode from the inside out for a long time out of sight, potentially weakening the structure behind the scenes. I-beam structures don’t experience that issue, of course, but are still vulnerable without proper treatment. Users have traditionally utilized hot-dip galvanizing to treat the steel. However, recognizing that the galvanized zinc is only intended to delay corrosion and not stop it, some companies have turned to epoxy paint as an enhanced corrosion protection measure. Epoxy coating creates a true barrier between the steel and any corrosive elements present, allowing for many more years of longevity for the building frame. Unlike a metal roof, fabric cladding itself is not susceptible to corro- sion, but it still must contend with weather and other influences over time. Polyvinyl chloride (PVC) fabric has been the preferred choice
for durable roofing and sidewalls. In recent years, some PVC offer - ings have been upgraded with additional coating layers, better UV in- hibitors, and cold cracking resistance down to -40 degrees Celsius. The expected longevity of the newer PVC is almost twice that of fabrics previously available. For applications like warehouse storage, fabric’s translucency allows users to take advantage of the natural daylight that permeates the roof, cutting down on the number of artificial lights needed inside. Fabric also moderates how outdoor temperature extremes feel inside the building, providing a cooler environment in the summer and warmer conditions in the winter. Rigid-frame fabric buildings are more airtight than comparable metal buildings, and the interior environment can be further controlled through the use of insulation and fabric liners. Insulated fabric struc- tures provide an ideal atmosphere for athletic and recreational facili- ties, where the fabric provides a soft reflective quality that lightens up the building and dampens echoes, contributing to a perfect ambience for sports and spectating. Optimal Delivery The process of installing a fabric building is also far more efficient than conventional brick-and-mortar construction. Aside from using materi- als that can be erected faster, some fabric structure suppliers can further expedite the process by handling every aspect of a project in-house. By employing their own design engineers, manufacturing I-beams and fabric panels in on-site facilities, and using their own professional installation crews – rather than relying on outside vendors for any of those steps – these companies can better stay on schedule, while also ensuring quality control for every component they touch. Today’s fabric building engineering, in combination with improved materials and processes, has allowed for the development of facilities that are cost-effective, custom-designed to the exact needs of the ap - plication, and of a much higher quality and longevity than the tension fabric structures of the past.
ERIC DONNAY is General Manager, Legacy Building Solutions
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csengineermag.com
October 2022
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