主题: canted bar jois
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旧 2009-09-07, 10:33 PM   #1
huangyhg
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默认 canted bar jois

canted bar joist
i am framing a monoslope roof (5:12 slope). for lots of reasons i would like to orient the joists perpendicular to the roof slope. in this orientation, the bottom chord of the joist will be 5" out of plumb from the top chord. my concern is the stability of the joist. i would appreciate any advice. i suppose i could brace the joist bottom chord to prevent the joist from kicking out but i am not sure how to put numbers on the problem.
thanks in advace.
check out our whitepaper library.
i found it.
someone in my office had a book, "designing with steel joists joist girders steel deck". the book discussed considering the "downhill" load when designing the bridging and/or roof diaphragm for "significantly tilted joists". significantly was identified as 2:12.
i think i'll flip the joists.
it's easy to design 'skewed' trusses... used them 30degrees from vertical and alternating to give the appearance of a space frame... deck takes tension at top and bridging at bottom. crushed tubes for web diagonals welding into the fillet of the top and bottom chord angles.
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