Built-up Wood Columns

[Engrman]

Hey all,

I've always assumed that wall sheathings such as plywood or OSB, if adequately nailed, laterally brace wood columns in walls. What do you guys think and is there a upper limit to that?

 

[civilperson]

Describe what you mean by a "wood column"? Is it similar to a 2 x 4 stud?

 

[theonlynamenottaken]

I personally agree with that. Especially if the sheathing is continuous across the member face (not a column next to an opening). If the column forms the edge of an opening I apply the old school "bracing capacity needs to be 2% of column axial load" rule and check the sheathing buckling and nailing. Of course, you may have blocking as well, which will only increase your lateral bracing capacity. Sometimes I specify where sheathing joints are NOT allowed to gain some flexural action from the sheathing if the panel width is small.

NOTE: Remember construction loads! I have seen wood axial members buckle prior to sheathing installation.

 

[msquared48]

Depends on the width of the OSB or plywood panel relative to the dimnension of the column you are trying to stiffen. If it's a four foot panel, no problem, but I would have a problem with only a foot.

I would consider gypboard the same way, but require a greater width of board to use as stiffening. This would apply to wood stud partition walls and bearing walls not used as shear walls.

Mike McCann
MMC Engineering

 

[UcfSE]

Would you still feel the same if the plywood or osb got ve'd out and replaced with gypsum board?

 

[msquared48]

UcfSE:

Not quite sure what you are getting at here, but, for any given width of wall, I would feel more comfortable with using OSB or Plywood than Gypsum for lateral restraint of the weak axis of the load bearing wall studs.

Mike McCann
MMC Engineering

 

[Lion06]

Mike-
I think that's the point he was making. If you design assuming you have plywood and then later on they decide to get rid of the plywood and forget to tell you.

 

[DaveAtkins]

And maybe this is obvious, but the sheathing will only brace the column in one direction. As with individual wall studs, buckling will still occur in the direction perpendicular to the sheathing.

DaveAtkins