Timber bearing wall supporting 2 different depth joists 1

[jie5]

Working on a timber framed structure and the architect is requesting 14" i-joists in certain areas and 9.5" i-joists in other areas. At some of the interior bearing walls both the 14"& 9.5" joists are to bear on the same wall. Looking for thoughts/input on the most practical way to frame/detail this joist bearing condition. See attached sketch.

 

[msquared48]

Well, you need a double top plate for the bearing wall, and the (3)2X4 should be (2)2X6 ripped.

But aside from that, I think I would consider using a 1.5 X 16" ripped microlam rim joist over the bearing wall and hang the 9.5" TJI's from the side of the rim joist, bearing the 14" joists on the top of the wall.

Mike McCann
MMC Engineering

 

[jayrod12]

I like mike's detail, but why wouldn't you just use an 1.5x14 rim joist? why bother ripping a 1.5x16, or use a 1.75x14 if you have to depending on availability of the others.

 

[jdgengineer]

I also would probably proceed with hanging in the smaller joists. I would personally use an LSL rim instead of an LVL rim. They should be cheaper, and are stronger in shear than an LVL. They should come in a 14" depth, so you wouldn't need to rip.

 

[jdgengineer]

Keep in mind though that when you are hanging into a 1 3/4 x rim you'll need to reduce the allowable hanger values to account for the shorter nail.

 

[msquared48]

jayrod12:

Yea, you're correct. 1.5 X 14'a. My typo.

Mike McCann
MMC Engineering

 

[OHIOMatt]

I do not design much with wood so do not take my idea as having any validity, but I am wondering if you could extend the bearing wall to the bottom of the subfloor and then use top flange hangers?

 

[msquared48]

I thought about that too, but you would have to watch the level of load to the double top plate. The use of the rim joist will avoid that problem.

Mike McCann
MMC Engineering

 

[jie5]

Thanks for the input. I an going to go with the rim board and joist hanger the 9.5" joists.

 

[OHIOMatt]

Thanks Mike. I never thought about using the top plate in bending, my standard note (when I do wood design projects) is to have the joists align with the wall studs. Maybe I am being too conservative. I will run through the numbers next time and potentially relax that criteria.