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Re: nailing zones in plywood diaphragms

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Ben Yousefi wrote:
>In many large diaphragms (i.e. tilt-ups) the nailing is divided into several
>zones with the nailing requirements increasing as it gets closer to the
>boundaries. My question is:

In tilt-up buildings you are most likely using a panelized roof diaphragm 
system that falls under Case 4 or Case 2,blocked of UBC table 23-I-J-1.  
Purlins spaced at 8-ft oc. in one direction and beams/girders at 20-ft or 
more the other.  

>At the transition from one zone to another, what type of nailing is
>required? Should the edge nailing of plywood pieces that cross over the
>transition line be:
In the case where loads are parallel to continuous edges or purlins(Case4) 
the transition occurs over a purlin and the nailing transition occurs on each 
side of the continuous edge.  In the opposite direction(Case 2, Blocked)  the 
transition should be laid out and dimensioned on the plans to occur at a 
panel joint.  Subdiaphragm analysis may  require the transition to be made at 
the first beam line.  I usually make the transition here.
>1.	The "boundary edge nailing" as required for the more restrictive
>zone. Yes on the side of the higher shear load. For Example: Draw a line the 
full width of the building.  The panel joint on one side is nailed at 3" o.c. 
and the panel joint on the other is nailed at 4" o.c.
>2.	The Nailing required for "other panel edges" for the more
>restrictive zone
Again, it depends on what side of the transition the "other edges" occur.
In Case 2 blocked diaphragm you are always at an "other edges" condition.
>3.	Other


Tom Jakaby, SE
Jakaby Engineering
San Jose, CA