Maximum Number of wood studs in a built up column

[awest]

Hello everyone, I am trying to find some information regarding the maximum number of wood studs allowed for a built up column. I believe it is 6 but I cannot find any reference stating that. Lets say I need (6) 2x4, is that allowed by code or is there a max number of studs allowed for a built up column.
Appreciate your help. Thanks!

 

[TehMightyEngineer]

I've personally never gone beyond 4 plys in a built-up member because it's usually cheaper and easier to just size a larger member or go to engineered lumber at that point. What's the application that you need 6 studs for?

Maine EIT, Civil/Structural.

 

[TehMightyEngineer]

I took a look in the NDS and 15.3 doesn't seem to limit the number of plys but does state that 15.3 applies to built-up members of 2 to 5 plys. It then states that built-up members shall have the plys individually designed if you don't meet the preceding assumptions (which includes the 2 to 5 plys statement). So, for practical purposes you're probably best off just limiting it to 5 plys.

Maine EIT, Civil/Structural.

 

[EngineeringEric]

(6)2x4 seems rather unstable as well, for that level of load i would think the header or post would almost have to be a 5.5 wide member. But i agree that i limit it to 4 jacks with PSL Columns being the next path before steel pipes.

 

[SlideRuleEra]

There has been substantial research into proper design of laminated wood columns with up to 4 plys. With more plys than that, spacing the joints so that they don't overlap becomes an issue. IMHO, would not go with more than four plys. Here is a typical article on the subject, there are others:

http://products.midwestpermacolumn.com/Asset/Nail-Laminated-Column-Design-ANSI-ASAE-EP559.pdf

http://www.SlideRuleEra.net

http://www.VacuumTubeEra.net

 

[EngineeringEric]

I don't think i would accept a splice in a typical column at all... or at least not in a timber column that is less than 12' tall

 

[awest]

I agree with you all. I think a PSL post would be a better choice. I was looking at 6 studs because I was assuming that (6) studs would be cheaper than 1 PSL post. Thank you all for you response. Really appreciate it.

 

[wadavis]

At that point we typically start considering a telepost instead. It saves space, is simple, and you can insulate around it if it is an exterior wall.
wadavis
E.I.T.

 

[racookpe1978]

At that thickness, could the OP use four 4x6's aligned so they are at right angles to each other, then cross-bolted to tie the 4x6 together?

 

[boo1]

Built-up columns may be either bolted or nailed and contain two to five laminations. There has been some discussion on this forum about fasteners penetrating all laminations.

 

[msquared48]

I agree with the five lamination limit, with the exception as noted under the five design provisions in NDS section 15.3.1 saying that more than five laminations need to be designed under 3.6.3 and 3.7.

Mike McCann, PE, SE

 

[Archie264]

I think years ago I was involved in a project where we may have used six…I wasn’t aware of the limitation at the time. But, that said, these were continuous members in “simple” residential construction. I wouldn’t feel good about any splices in a laminated column, even if they are allowed. It sounds like the research is there to support it so I’m sure it works, I would just choose not to design a situation where that was required. At that point I’d consider going to steel pipe columns, er, round HHS sections, I guess they’re called now.

 

[msquared48]

Years ago, rather than add metal bearing plates where the sill plates were overstressed in bearing, we would just add more studs to increase the bearing area - got up to 8 studs at times as I remember.

Mike McCann, PE, SE