Heavy snow accumulations on the roof of an elementary school in central Oregon in January 2017 caused structural damage to six wood roof trusses that span approximately 75 feet. The trusses were found to have some bolted connection failures at the heel plates as well as three split and fractured web elements associated with their bolted connections. The snow load on the roof was reportedly around 40 pounds per square foot, while the trusses were initially designed for 30 pounds per square foot. Despite the significant snow load imposed on the trusses with compromised heel connections and fractured web elements, they did not collapse or exhibit excessive deflection. After an initial assessment in January 2017, other engineers designed and directed temporary repair and stabilization for the trusses to allow for continued occupancy until a permanent repair could be determined and implemented.
This article was originally published in the February 2018 issue of STRUCTURE magazine, exclusively published for the practicing structural engineer.
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