Recessing bolts in built-up PSL column

[McSEpllc]

Hi All,

Using NDS-18, §15.3.2 and 15.3.4 (pages 149 and 150), and its commentary C15.3.4 (page 280), on bolted built-up wood columns: It does not seem to address whether it is permissible to recess the through bolts and washers.
Does anyone know?

I am hesitant to recess the bolts and washers without some code reference, considering how much the column stability factor Cp is reduced by building-up through-bolting already.

Appreciate it.

 

[KootK]

1) I'm afraid that I don't know of a code reference either so my help will be of limited value.

2) The recessing may affect your cross sectional checks, sans stability, owing to the material removed (obviously). This won't matter much, though, if your design is governed by stability as I suspect.

3) I would argue that bolt recessing will have little to no effect on your moment of inertia for the built up member which is the main thing for stability. As such, in the absence of a code reference on way or the other, I would be comfortable saying that the recessed holes do not affect buckling capacity. You know, unless there's truly lots and lots of bolts for some reason.

 

[McSEpllc]

Thanks for your thoughts KootK.
The Weyerhaeuser engineer thought the same about the recessed holes.
I am still pondering.