Jeff Smith wrote:
> If this is the case, wouldn't a concrete shearwall or braced frame be even
> stiffer relative to the diaphragm compared to a plywood shearwall and
> therefore justify a flexible diaphragm?
It would most of the time. My differentiation was based on the fact that there
is an absolute drift limit (1630.10) for non wood vertical elements of lateral
systems and this requires you to check diaphragm deflection to assure that it is
more than 2x story drift. In a long narrow building a diaphragm could be rigid
one way and flexible the other. At least the code thinks so.
I believe Frank McClure's post on the subject was right on the mark.
I have contacted Jim Hodges at ICBO. They really need to address this issue.