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Re: wood diaphragm edge / roof venting

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At 09:58 AM 06/15/2000 EDT, you wrote:
>continuous ridge vent is not an option because it would cause a diaphragm 
>discontinuity.  Is there any published information reagradingimpact on 
>plywood diaphragm strength of drilling holes in plywood at the ridge (say (2) 
>- 2" diameter at each space each side of ridge?)
The matter can be evaluated by resort to APA's Plywood Design Spec., from
which allowable in-plane shear stress of the sheathing material itself can
be calculated. For thicknesses typical of roof sheathing, this shear value
is approximately double code-listed diaphragm shear values obtainable with
the closest spacing of 10d nails. Sheathing strength is not remotely the
limiting condition in the assemblage.

Additionally, diaphragm shear at the ridge line is apt to be considerably
less than at other locations in the diaphragm.

Use of holes for venting would seem to be structurally viable.

Charles O. Greenlaw SE   Sacramento CA