Concentrated Loads on Plywood
Concentrated Loads on Plywood
(OP)
I have searched high and low for allowable concentrated loads on plywood of various thickness and joist spacing. Anyone know of such an animal?
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Concentrated Loads on Plywood
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RE: Concentrated Loads on Plywood
The APA (American Plywood Asssociation) has a specification that provides allowable stresses in plywood - both for stresses in the plane of the sheet and across the plane.
Most codes like IBC provide maximum spans based on uniform loads but that is not what you are looking for.
The only way I know to check plywood for a concentrated load on a span of plywood would be to get the APA specification and use basic statics, analysis, etc. to determine shears and moments in the plywood - get the stresses - and then check against the APA allowable stresses.
I got the attachment below from www.apawood.org
RE: Concentrated Loads on Plywood
RE: Concentrated Loads on Plywood
Perimeter of point load X Fvtv = Punching Shear Capacity
F sub v t sub v is the "Panel Shear Through The Thickness" value listed on Page 21, Table 4B in APA's 28 page "Panel Design Specification" dated 2008. The document he sent me was D510.pdf. It is also listed with respect to span rating on pg. 18, Table 4A. Table 4B gave the most conservative value based on thickness of 105 vs. 115 on Table 4A.
So for my floor with a 4"x4" square point load on 23/32" AC plywood the value is 16 in x 105 lb/in = 1680 lb! I assume this is for the max. support spacing of 24" since the product is rated 48/24. My joists are 16" o.c.
Other load cases such as bending and deflection certainly control this design. I guess this calc would be most applicable for small footprints like a 1" square.
RE: Concentrated Loads on Plywood
RE: Concentrated Loads on Plywood
RE: Concentrated Loads on Plywood
RE: Concentrated Loads on Plywood
To complete this post, I'll attach the document I was referring to above.
RE: Concentrated Loads on Plywood