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Re: nailing zones in plywood diaphragms

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Roger Turk wrote:
>I don't see why changing the nailing zones of diaphragms would be any 
>different than what is done in changing the spacing of stirrups in concrete, 
>or stiffeners in built-up girders, or discontinuing reinforcing steel, or 
>changing cover plate sizes.  You take the closer spacing/greater capacity 
>requirements out **beyond** the point where larger spacing/less capacity 
>becomes adequate, and repeat as necessary.

I agree the transition should be made beyond where the higher capacity is 
required.  
>At the point that the change is made, the closer spacing/greater capacity 
>elements are already much stronger than is necessary for the force at that 
>location (unless, for example, the change in shear is the result of a 
>concentrated load) and the closer spacing/greater capacity elements are 
>(should be) slightly stronger than is necessary for the force at that 
>location.  To space nails differently on one side of a plywood joint than on 
>the other side is absurd.

It is NOT absurd to space nails differently on one side of a plywood joint 
than on the other!  This is exactly where the transition should take place.  
If not there, then where?  The next time you have the opportunity to look at 
a large diaphragm you may notice that the transition usually occurs at 
continuous panel joints and along other edges or collector lines.

Making the transition in a logical place provides the builder with accurate, 
precise information and satisfies the engineering requirement accurately and 
precisely.

J. Thomas Jakaby, SE
Jakaby Engineering
San Jose, CA

>Strive for accuracy, and don't worry about precision!

>A. Roger Turk, P.E.(Structural)
>Tucson, Arizona