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Re: Wood structure with wood diaprhagm - question on disconntinuity

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In a message dated 9/30/99 11:11:22 AM Pacific Daylight Time, 
Seaintonln(--nospam--at) writes:

<<In the old flexible diaphragm design I would generally consider the beams 
be a hinge in the diaphragm and design some or all of the columns to be 
laterally restrained. However, in the new methods the roof should be 
considered monolithic in nature and capable of distributing shear to the 
extreme edges.
If I use the columns as I would in the past, I must penalize the structure by 
using an R of 2.2.>>


I have had situations similar to what you described. If you can transfer the 
shear through the pony wall (which should be minimal since the roof break is 
in mid span of your diaphragm) then all you have to do is develop your chords 
at the ends of the roof break (i.e., at the side shear walls) and you are 
done. I don't think you need the flag poles, but you do need to check the 
stability of the posts due to the diaphragm deflection.

You can model this with a calcpad backer. Just fold it the way your roof is 
and put it up right and support the ends and push the upper mid point gently 
and see what happens.


Oshin Tosounian, S.E.