Wood Column Supporting Steel Beam

[cuels]

I recently inspected a residential home that was being framed. The structure is a wood framed structure except for a steel beam that was supporting the second story floor. The contractor originally intended on placing the beam in a wood beam pocket with several 2x6 studs nailed together as the column. However, they decided to move the beam up into the floor (joist) space. To correct the height issue of the column/beam pocket being too short, they stacked several plies of 2x6's (flat) across the top of the column to build up the column to the right height to bear the beam. This column is located in an exterior wall, so the column will be tied to the plies of 2x6's with the exterior wall sheathing (OSB).

Also, as a result of placing the beam in the floor joist space, they had to discontinue one of the top plates. However, there is only about 2' of lap on the top plates on one side of the beam.

The beam is a W10X49 which supports a trib. width of 15' of residential floor. The column in question is located in an exterior 8' wall.

I am looking for advice on whether anyone thinks that these situations are an issue. It is in my mind, but if anyone has comments and/or solutions to correct the problems, I would appreciate it.

 

[msquared48]

1. By filling the gap with 2X flat, there will be vertical shrinkage issues that would not have been there if the column studs were full height. You need to shore the beam and replace the studs full height, adding the tab plates mentioned in #3 below.

2. The cut plate and splice can be remedied with a steel strap across the 2' splice - something like a Simpson MSTI48 or equal, with the center of the strap aligning with the splice. The single stud plate should be able to transfer any drag forces.

3. There should have been tab plates welded to the W10 to nail thru to the wood column. Otherwise, the steel beam could pull out from the wall.

Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask

 

[hokie66]

Agree with Mike that cross grain shrinkage is an issue. Also perhaps bearing stress perpendicular to grain.

 

[cuels]

The beam has been attached to the column by drilling a hole through the bottom flange and lag bolting the beam to the column. Is this an okay way of fastening the steel beam to the column?

My concern with the column is that the flat 2x's create a hinge point in the column, therefore, creating an unstable structure. Am I trying to overthink this, or is this a valid point? I know that the column is tied together on one side by the wall sheathing, but the other side will only be connected by sheetrock (of course assuming that cross grain shrinkage is ignored and the column is left in place as is). In my mind, if there are ever any eccentricities or other random events that cause the column to move out of plane with respect to the hinge point, the hinge point will become a concern. So, with the nature of wood framing, would there be enough connections holding things together that this wouldn't be a valid argument, or are there too many variables to make a good judgment? I guess, if the contractor says that they don't care about the cross grain shrinkage, would this column still bear the weight for the life of the structure (minus a few cracks in the sheetrock)?

 

[msquared48]

With the blocking, definitely no.

With a full height column, this would be lagging into the endgrain, a definite nono.

So, no.

Yes the column would bear the weight, but the connection of the beam to the column is not, and cannot, be good. As I said before, the column needs to be replaced with a proper connection installed.

No compromises here.



Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask

 

[demayeng]

The hinge is a valid point, but you can check if it is an issue or not by doing a rough check of the bending from wind (or from an assumed eccentricity of vertical load) at the junction between the column and the first ply and check how much tension there may be in whatever connection (eg nail) is there.

If the connection is not up to the job, you could use metal straps looping over the top under the beam and nailed down the face of each column to assist it.

 

[msquared48]

cuels:

Considerng further on the column flat blocking, I do not think that the blocks could be installed without splitting due to the short length, considering the nails that would be needed to keep them together. Plus, they would have to be nailed into the endgrain of the column, a nono. Lags tghru the flange into this assembly would only make matters worse.

I also agree on the hinge problem.

Just tell the contractor, and owner, to do it right. Don't gerryrig it.

Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask

 

[BAretired]

I agree with Mike. It is unacceptable as is.

BA