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RE: "R" Value

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Since nothing is set in stone these days, my opinion is that the smallest R
should be used that represents the most flexible system acting in each
direction of applied loads. In a box system where only plywood shearwalls
are used, an R of 5.5 is allowable. However, in some areas this will yield a
base shear of around 14.7% which is not enough for some of us who designed
in the previous code using an Rw of 6 rather than 8 to compensate for
possible deficiencies in construction. Using R of 4.5 may be more
conservative (in a plywood box system) but should be  left to the discretion
of the engineer of record.
The problem, in my opinion, is that the current code tries to make these
determinations for us rather than letting us decide when it is appropriate
to add strength.

Dennis
-----Original Message-----
From: FSRahbar(--nospam--at)aol.com [mailto:FSRahbar(--nospam--at)aol.com]
Sent: Tuesday, December 14, 1999 2:57 PM
To: seaint(--nospam--at)seaint.org
Subject: "R" Value


The big "R". Where a building has bearing wall system in both direction, can
different "R" values be used for different directions. For example R=4.5 for
N-S direction and R=5.5 for E-W direction. The building is rectangular in
shape.

Thank you,

F S Rahbar