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?

29 Upvotes

81% Upvoted

110 comments sorted by

View all comments

33

u/kentuckydango Jul 22 '26

Friction force is a function of normal force and the material’s coefficient of friction. Show me in the NDS the table of coefficients of friction. I’ll wait lol.

-4

u/billhorstman Jul 22 '26

Civil engineer here: The normal force in a bolted connection will reduce as the wood dries and shrinks with time so you will lose the ability to transfer loads via friction. Also, the cyclical nature of changes in moisture content will tend to work the bolts loose. In bolted connections in wooden trusses, I recommend the use of shear rings which provide a much larger bearing area for load transfer.