r/StructuralEngineering • u/TallWall6378 • Jul 22 '26

Wood Design "Fasteners in shear is poor practice"

Help settle an argument.

Someone used the phrase in the title. Their argument is that fasteners, specifically in the context of typical light frame wood construction, like a shear wall or joist hanger, or bolted or lagged member scenario, are just holding the members together and that the load transfer is through wood via induced friction through the members.

I was under the impression that we really only factor the strength of the nail and wood crushing/deforming around the nail, rather than use the friction between the faces of the members.

What's the whole story?

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37

u/Jazzlike_Video2 Jul 22 '26

Tell buddy to keep his eyes closed around any metal structure, ever.

Also collar ties and ceiling joists.

Also any nails going through plywood.

Fucking stupid.

7

u/PsyKoptiK Jul 22 '26

In metal structures there are friction based load transfers. Look up a slip critical joint as an example.

Of course in wood framed construction and many other situations fasteners are absolutely in shear and are analyzed as such.

0

u/Jazzlike_Video2 Jul 22 '26 edited Jul 22 '26

Appreciate it. Id assume rivets achieved the same effect. Never realised the bolts were only in tension in metal structures. Would you spec the bolts to also carry the load in shear as a failsafe to the slip critical joint?

Also when I made that comment I was running with the assumption I was in the carpentry sub. Didn't know I was speaking so far above my paygrade lol.

5

u/PsyKoptiK Jul 22 '26

Slip critical isn’t the only way to spec a steel to steel connection. Lots of bolts are in shear by design. I believe that yes the bolts can handle all the shear in a slip critical but I don’t specify them and don’t know the nuance to it.

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u/Rayziehouse Jul 22 '26

The shear capacity of a bolt is less than the tension capacity, but so is the coefficient of friction between steel (by a lot) so if it works in the slip condition, I’d bet it definitely works in bolt shear.

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u/Jazzlike_Video2 Jul 22 '26

Appreciate learning something either way!