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Roof diaphragm


From this plan of a simple wood frame structure (1-story height), what is the maximum chord force at the east and west edges of the roof diaphragm if 110 lbs/foot lateral wind load is exerted as shown?

A. 18,340 lbs
B. 367 lbs
C. 3,670 lbs
D. 4,600 lbs

AnswerD. 4,600 is correct. The lateral wind load here is similar to a uniform load acting on a simple beam turned on its side. To find the maximum chord force at the edges of the diaphragm, use the equation for maximum moment wl²/8 ÷ building plan depth. 110 lbs per foot x (100 ft)² / 8 ÷ 30ft = 4,583.33
ARE 4.0 exam prep: SS

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