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
>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
J. Thomas Jakaby, SE
San Jose, CA
>Strive for accuracy, and don't worry about precision!
>A. Roger Turk, P.E.(Structural)