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Re: Plywood Floor Diaphragm Shear Values

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Also, consider that the minimum nail embedment in many i-joists will not be acheived, as many 'i'-joists have flange thicknesses of between 1-5/16" & 1-1/2".  Therfore increases due to 10d and larger diameter nails will be questionable.
Pat Clark, P.E.
From: George Richards P.E. <george(--nospam--at)>
To: 'seaint(--nospam--at)' <seaint(--nospam--at)>
Date: Monday, February 18, 2002 10:45 AM
Subject: RE: Plywood Floor Diaphragm Shear Values

Paul, The APA has a publication for this.  There is no discussion in it regarding slightly wider giving slightly more.  Also thicker PW will not necessarily give you more load since the nails will govern the design.
George Richards, P. E.
-----Original Message-----
From: Paul Crocker [mailto:paulc(--nospam--at)]
Sent: Monday, February 18, 2002 10:03 AM
To: 'seaint(--nospam--at)'
Subject: Plywood Floor Diaphragm Shear Values

Does anyone have any experience or a good reference regarding calculating plywood floor diaphragm shear values for conditions other than those listed in UBC Table 23-II-H?  I was reading the table recently, and it occurred to me that the largest diaphragm values are for 19/32" plywood, while I typically call out 23/32" plywood.  Also, on at least one project I am using TJI 250s, which are slightly wider than 2x member but not as wide as 3x members (the only two sizes shown in the table).  I would assume that I could use slightly larger values for these conditions compared to 2x members and 19/32" plywood, but I am not sure how to go about calculating this since there are quite a few mechanisms that could control, and I would guess that most of these are based on testing.  Any suggestions or references would be appreciated. 
Paul Crocker, P.E.