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Re: Wood: Are you as confused as I?????

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In a message dated 8/17/99 12:48:20 PM Pacific Daylight Time, 
Eagonzal(--nospam--at)ENG.CI.LA.CA.US writes:

<< It could be that this is due to a statement regarding Section 91.2315.1 
about
 not considering torsion.  Apparently, this section is only intended to 
address
 open front buildings and modifies what is in the UBC.  I think Dennis may be
 able to expand on this much more.
 
 ed gonzalez >>


If I recall correctly, this section was adopted to compensate for soft-story 
failures where there was no lateral support provided at the open front. The 
original methodology allowed for the shear due to torsion to be redistributed 
to the three remaining walls which proved to be in inaccurate assumption 
considering the structure failed the same as would be expected from an open 
box with the support of the flaps. The deformation at the front caused 
considerable deformation to the point that the garage header / column or pier 
filed and the roof collapsed.
I also recall that the provision was intended ONLY for open front structures 
with living units above. Garages were still allowed to be designed by torsion 
since they were considered a low risk.

Someone still in Los Angeles may be of more accurate memory than I.

Dennis S. Wish PE