Subject: Re: Rigid vs Flexible Diaphragms - Some Comm
Date: Fri, 7 May 1999 15:35:50 EDT
For those who asked, the ICBO Seismic Design Manual in Volume II in the Wood
Framing example number I (the last draft version) indicated that the APA is
working on an easier method to calculate the deflection of a flexible
(unblocked) diaphragm, however, it is assumed to be 2 to 2.5 times the rigid
diaphragm calculated deflection as noted in Volume III (or the Standards).
The example recommends that the engineer use 2.5 times the calculated blocked
diaphragm deflection and I believe this is considered the standard until
something more exact comes along.
Dennis S. Wish PE