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Component Manufacturing dverti$er
Don’t Forget! You Saw it in the
Adverti$er
April 2019 #11237 Page #44
Steps to Minimize Snow Load Failures
E
arly every year, the National Frame Building Association (NFBA) holds its annual Frame Building Expo—where thousands of postframe builders, design professionals, and vendors meet for three days filled with break-out sessions, guest presenters, and, of course, a trade show.
By Mike Momb The Pole Barn Guru
In 2015’s Expo, one breakout session was, “Avoiding Common Building Failures in the Post-Frame Industry,” presented by Ryan Michalek, P.E., of Nationwide Insurance®.
The “trailer” for this session was, “Would you find it surprising that Nationwide Insurance’s loss experience with post-frame buildings is disproportionately represented by newly constructed facilities? The company’s loss history is full of buildings that are less than 5 years old and that fail when subjected to their first moderate wind or snow loading event or to a modest commodity-loading cycle. This presentation discusses the common oversights in post-frame building design and construction which lead to building loss and offers strategies to eliminate these oversights.” I quizzed Mr. Michalek myself as to how many of these failures were subjected to a structural plan review by a Building Official. His opinion was few, if any, failed buildings were designed by an RDP, registered design professional (registered engineer or architect), as they are nearly exclusively “agricultural” structures, exempted from Building Permit processes in many states. My personal belief—every building should be designed by an RDP, as well as be subjected to structural review by a Building Official. Knowing the Insurance Industry size, I questioned why it was Nationwide and other insurance companies were not lobbying for stricter rules for these now permitexempt buildings. Mr. Michalek minced no words in stating the United States agricultural lobby has far more power than the insurance industry lobby. I just don’t understand the thought processes of those who would invest in buildings which will underperform or fail structurally, all for saving a few dollars. Considering many failures come from poultry industry buildings, it seems costs and cleanup of a million dead chickens or turkeys would trump a few dollars saved on construction. What was surprising to me was an analysis of actual most-prevalent failures—although column size and embedment always seem to be big concerns from informed purchasers, this wasn’t a contributor to three major causes of failures: lateral bracing of trusses, purlin to truss connections, and unbalanced and snow drift loads on trusses. Typically, builders, when they do install bracing, will just run it laterally from building end to building end. This results in all trusses bending together, as loads being placed upon bracing are not being transferred to a very stiff surface—like a roof diaphragm. By utilization of properly designed “X” braces, lateral loads can be transferred into roof plane, and keep trusses where they are happiest—upright. Continued next page
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