W Beam supported on.... 1

[RareBugTX]

Hello all:

Want to know your take on the topic of steel beams supported on wood columns or built up wood columns. I know it is generally not recommended, though allowed by some codes the support of masonry on wood. I know my wood column will be just fine, but want to know your practice and opinions. Applicacion is a residential rehab. Span is 16' and dead and live loads are residential. Axial loading only.

Look forward your feedback

RareBugTX

 

[XR250]

I do it all the time...

 

[KootK]

I have no problems using steel wide flange beams in wood construction so long as the important, mixed materials considerations are addressed. Some of those would include:

1) Bearing stresses where the steel beam bears upon wood. Oftentimes, stresses can be higher than they would be with a typical wood beam.
2) LTB bracing of the steel beam. There needs to be torsional restraint either along the beam at intervals or, at minimum, at the ends where the beam frames into the columns.
3) Shrinkage compatibility. Depending on the situation, I may add wood plates to the top and/or bottom of the steel beam. This is more of a new construction thing.
4) Moisture. Depending on the application and building envelope details, steel beams can be magnets for condensation which doesn't play well with wood systems.

My understanding is that the code prohibitions on supporting masonry with wood are mostly about stiffness compatibility. I've taken some liberties with those rules when I've felt that I've provided a sufficiently stiff supporting system. In your case, that may well be why you're using a steel beam. You should also consider any deformation that may accrue from top and bottom plates etc as well.

What manner of masonry support is your steel beam going to be providing? Often, steel beams are used in wood stud walls to support brickwork positioned eccentrically to the shear center of the steel beam. That induces torsion in the steel beam and can get ugly if the rotational restraint details are properly tended to.


The greatest trick that bond stress ever pulled was convincing the world it didn't exist.

 

[msquared48]

I would have no problem with the wood column considering vertical shrinkage compatibility.

Mike McCann, PE, SE (WA)

 

[jayrod12]

Like excel, I do it all the time, do your bearing checks as KookK mentioned. Sometimes, depending on the situation, I will specify LVL studs below the steel beams to help with the latter two issues of KookK's list.

 

[Triangled]

Don't see any problem either. I've placed bar joists on wood framed walls. Sometimes tradesman may feel a bit challenged, but careful detailing and notations can be sufficient.

 

[KootK]

@Triangled: did you ask for the studs to be located under the bar joists? Or was the top plate able to get the job done as a distribution member? I've only tried that scheme with light gauge.

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough that I want to either change it or adopt it.

The greatest trick that bond stress ever pulled was convincing the world it didn't exist.

 

[Triangled]

@KootK: I've used this scheme when the loads were a little bigger than what I'd typically utilize a wood truss for, and, consequently, the truss reactions being bigger, I inevitably specify that joists be located directly over post or multiple studs.