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Component Manufacturing dverti$ dverti $ er
Don’t Forget! You Saw it in the
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August 2022 #14277 Page #10
The Development of the Truss Plate Part 1: The Perfect Storm nearly perfect confluence of circumstances combined to create the truss plate in South Florida. The wartime home-building hiatus, the post-war baby boom, and the northward (from Cuba) and southward (snowbird) migration to Florida all combined to skyrocket the demand for new housing. But what made the most impact, literally, was the force of hurricanes, and the competition to design a system to withstand them.
By Joe Kannapell
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Four consecutive years of devastating hurricanes hit South Florida beginning in 1947 when 140 mph winds hit Miami-Dade County head-on. In 1948, a second one with 110 mph winds hit from the opposite direction, and in 1949 a third storm came ashore, continuing the carnage. If those weren’t enough, the worst one hit in 1950, the first year names were given to hurricanes. This one was appropriately called “King” and its 150 mph winds damaged some 21,000 homes. That’s why the Dade County building department had no choice but to raise roof loading to 55 psf, the highest in the country (while the state of Florida did not require adherence to a building code until 1974).
By the early 1950s, residents were retreating inland from the coast, onto the edges of the Everglades. There, foundations had to be more substantial than simply concrete slabs over sand, creating a strong incentive to avoid interior footings, and encouraging the use of clear span trusses. But Dade County Officials, in order to make sure these newfangled wood trusses (and their connections) would stand up to severe wind loads, developed a truss-testing criterion by working with Cal Jureit, the Chief Engineer at a local testing lab. As a result, building permit applicants specifying trusses were required to submit full-scale truss tests, certified by an engineer, to back up their design methods. Critical to passing truss tests were the connections. Continued next page
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