Screw Connected Plywood Diaphragms 2

[brph94]

I have been looking for load tables for screw connected plywood diaphragms
connected to wood framing. Does anything like this exist, I have seen some proprietary
things by fastener manufacturers.

 

[StruteK]

I would take it as the capacity of a nailed diaphragm with nails of the same diameter as your screw. Ensure the lateral resistance of the screw is greater than the nail.

 

[msquared48]

... And the embedment of the screw is equal to or greater than the nail.

Mike McCann
MMC Engineering

 

[dhengr]

We know what an 8d or 10d common nail is, and we can (or the AF&PA has) tested these at various spacings with various plywoods and OSB’s, etc. In your area there are probably only 8261 different types of screws, so that testing is likely going to have to come from each screw manuf’er. To many over driven nails start to reduce the shear strength of a plywd. shear panels, and this will be true of screw too, which are notoriously over driven.

 

[Gumpmaster]

I don't think there's a 1 to 1 comparison with screws/nails for the same diameter and embedment, especially for seismic diaphragms. Nails provide ductility through both the steel yielding and pullout of the nails. Screws have neither ductile yielding or pullout. You get a much more brittle, sudden failure. Some of the major screw manufacturers may have testing that provides diaphragm capacities, but I wouldn't just assume that they're equal to the nailed capacities.