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Need some advise on Rigid Diaprhagm Analysis Results

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Subj:   HELP - Rigid Diaphragm Analysis - need advice.
Date:   8/25/99 3:15:18 PM Pacific Daylight Time
From:   <A HREF="mailto:Seaintonln";>Seaintonln</A>
To: <A HREF="mailto:seaint(--nospam--at)">seaint(--nospam--at)</A>

I just completed a fairly simple (but irregular) 4000 square foot single 
story wood framed residence. The flexible diaphragm analysis yielded 
predictable results that were no surprise.

I compared the results of walls to the rigid (torsion) analysis and came up 
with values that are unreasonably high. One line of shear yielded a capacity 
of 3,595#  from the flexible analysis and 13,108# from the Rigid Analysis. 
All other walls appear to be relativly close to the flexible results except 
this one. 10,267 pounds of it were due to torsion. The diaphragm is only 50 
feet deep and the wall is about six feet from the back wall of the garage and 
then 29 feet to the next line of shear. In the three lines of shear, the 
walls are all about the same length and the same capcity or stiffness based 
on the flexible analysis. 

I don't trust these results. Is there any shortcut check that I can apply to 
verify the results?  Can anyone offer any suggestions or advise me as the 
best way to circumvent the potential problem of the plan reviewer 
interpreting my results and making me comply with a result I don't feel is 

The wall is 12 feet long and 10 feet high. There are no cutouts in the 
diaphragm which is essentially 110 feet wide by 40 feet deep (with some jogs 
to reduce the area of the diaphragm to 4000 square feet).


Dennis S. Wish PE