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Displaced Center of Mass Question

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The design examples from the Feb 1998 SEAOC Wood Seminar for the 97 UBC (and 
the draft of the ICBO Design Manual Volume II) note "by displacing the center 
of mass by 5% can result in the C.M. being on either side of the C.R. and can 
produce added torsional shears in all walls."

However, the Reinforced Masonry Engineering Handbook by James Amrhein (5th 
edition 1994 UBC compliant) simply adds the 5% of the diaphragm depth 
perpendicular to the direction of loading and adds it to the difference 
between the C.M. and C.R.. - leaving the displaced C.M. in only one location.

Which is considered the standard of practice in rigid diaprhagm analysis?  If 
the more involved method is applied in wood construction, has anyone been 
able to calculate a significant difference in added shear from torsion?  If 
so, how many of these buildings were residential (single and mulitple 
residential) etc.

Dennis Wish PE