Return to index: [Subject] [Thread] [Date] [Author]

re:nailing zones in plywood diaphragms

[Subject Prev][Subject Next][Thread Prev][Thread Next]
         \'\                                                     __________
         / '|                From the Desk             ()_________)       
         \ '/                                                     \ ~~~~~~~ \ 
           \                          of                            \ ~~~~~~  
         (==)                                                     \____~~___\
         (__)                  Dennis S. Wish PE                    

Dear Ben, 

This is an interesting question. My opinion is that this is a transitory zone 
and the exact location of change from a blocked diaphragm to an unblocked 
diaphragm is only calculated and not exact. The fact that the panels are 
lapped (load case 1) for example, would place both boundary and field nailing 
in the same line of shear.
I would think that that the change in spacing and addition of blocking should 
occur in the zone of lesser shear for the panels that overlap this imaginary 
The real case will be how it is interpreted by the contractor in the field - 
more than likely he (or she) will change the spacing of the nail to the 
critical side of the zone line.

I would assume that it would be save to consider the imaginary line of zone 
change to be the blocked line and make it boundary nailed for conservativism.

In reality, the load is proportionally changed and therefore the change at 
the transition zone would seem less critical than a few feet further on the 
high side.

I hope this addresses your issue.

Dennis S. Wish PE
Structural Engineering Consultant