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# Re: More questions about rigid plywood Diaphragms

• To: seaint(--nospam--at)seaint.org
• Subject: Re: More questions about rigid plywood Diaphragms
• From: Seaintonln(--nospam--at)aol.com
• Date: Sat, 3 Jul 1999 14:17:46 EDT

```There is a design example of solving a plywood shearwall with an opening in
the seminar notes from the February 1998 '97 UBC Seminar" conducted by
SEAOSC. The example came from Ron Nelson and Doug Thompson and I would
recommend that you contact SEAOSC (seaos(--nospam--at)aol.com) for a copy of the notes or
see if Ron Nelson can provide you with an example at no cost.

Dennis S. Wish PE

PS. We are all in the same boat as you are an probably more confused:>)

In a message dated 7/2/99 7:04:23 PM Pacific Daylight Time,
jbotch(--nospam--at)isp1.blissnet.com writes:

<< I hope you all have a nice independance day holidy.

I'm going to try to ask the same question to this topic that I did last
week, different wording maybe.  We're still all into the discussion of
rigid plywood diaphragms vs flexible.  A little more to the point this
time.  IS THERE A RATIONAL METHOD FOR CALCULATING THE DEFLECTION OF A
PLYWOOD SHEARWALL WITH OPENINGS?  Is the reason there was no reply to my
last message, a stupid question, maybey ignorance on my part, or are the
rest of you in the same boat as I?  Calculating loads to shearwalls
assuming a rigid diaphragm, is not an overwhelming task.  Most of us
have either been given a spreadsheet to do this or we've produced our
own.  Calculating loads to walls for flexible diaphragms is also no big
deal.  My problem (once again) is how to determine the rigidity of a
plywood shearwall with openings.  Maybe the rest of you design buildings
with nice neet walls of discreet height and length.  Frankly in 15 years
I've yet to see it.  Once again, my opinion is if you can't determine
the wall deflection, hence its rigidity, THE ARGUMENT BETWEEN FLEXIBLE
VS RIGID IS BOGUS.  You can't make the "rigid"  assumption of a rigid
diaphragm and then distribute the loads by an arm-waving assumption at
the walls.

Come on people, tell me I'm crazy, tell me why I'm crazy, give me
something more than unsubstantiated emotion.

Joe Grill
>>

```