Offsetting basement beam from 1st story load bearing wall

[jimtheengineer10]

A contractor asked me if he could offset the beam in the basement about 4" so it is not directly under the 1st story load bearing wall. The reason he asks is that he wants to run his plumbing down the wall but if the beam is directly under the wall he can't. He said he always ends up building basically a 2x8 wall so he can run his plumbing down and have it pass besides the beam.

So the load bearing wall would sit on the floor joists about 4" away from the beam. Would I need to just add a point load at this location to the floor joist and see if it works or are there other things I need to be thinking about?

 

[msquared48]

Just see if the floor joists can take the additional shear.

In that the NDS allows uniform loads to be ignored a distance "d" from the end of the joist, you will still need to consider this as it is a point load to the joists.

However, usually shear will not control for the initial sizing, so, at only a 4" offset, this should work. Do the math.

Mike McCann, PE, SE (WA)

 

[jayrod12]

No you have the gist of it. Provided the floor joists are sized appropriately for the line load I wouldn't see that being an issue. 95% of the pre 1990 houses I've looked at it's been anywhere +/- 18" on either side of the main floor beam.

 

[KootK]

Two additional considerations:

1) If it's a transferred shear wall, there would be additional things to worry about.

2) Your single, sometimes spliced, bottom plates now span between floor joists if the joists and studs do not align.

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 to either change it or adopt it.

 

[wannabeSE]

Also, remember to check the joist to beam connections for the added load.

 

[XR250]

Kootk makes good points. This may not apply in this situation, but I see it in crawlspaces all the time, the additional load can wreak havoc on ledger strips that are used to support the joists.