Using Wood Sheathed Wall As a "Deep Beam"

[cal91]

I have a 52'-0" long wall on a second story. It has 30'-0" of roof trib (12 psf DL). The owner needs the space below that to be open. I try supporting the wall with perpendicular joists but they get killed. I would need a W24X62 steel beam at the roof level, and I don't know if they can ship a 52'-0" long beam out anyways.

Can I not simply use the wall as its own beam? I'd find the max shear and design the sheathing accordingly. I'd design the top and bottom plate for the chords forces. Has anyone ever done this, or is this crazy sauce?

 

[cal91]

I've pushed the architect / owner on aligning the walls but this is how they need it.

 

[CANPRO]

If you use the steel beam option, be sure to specify some sort of deflection track/connection between the wall and beam. With the wall bearing on the joists so close to the supports, they’ll end up taking significant roof load that was meant for the steel beam.

 

[KootK]

Got it. At the risk of being obstinate, I still feel as though my 2 ply, 24", 1/4 PT LVL solution should work. In what way does it fail? The load is only 4' from the end so, unless it's shear, I'm having a tough time seeing it.

 

[CANPRO]

Sorry, didn’t see that you had already mentioned you’re using slotted clips under the beam.

 

[CANPRO]

If KootK’s idea fails just on shear, this might be a good use of a flitch beam. The steel plates would probably only have to be on the last 6’-8’ of the beam.

Alternatively you could put larger beams at 1/4 points and turn your joists the other way. Cuts your joist span from 32’ to 13’ and savings pay for the beams.

 

[cal91]

Are you guys talking about the same idea?

 

[cal91]

The problem is the owner doesn't want solid web members. That' why I'm using Red-L joists. I do appreciate the ideas and suggestions though, if it weren't for open web requirement I'm sure that would be a superior option.

 

[KootK]

Pretty close.

You don't need LVL at the far sides of the 52' width do you? I'd have thought that could be bearing wall.

I like what you've shown if it works but another way would be to move the three shorter beams up to the roof level supported on posts that hit the LVL below. That way you could retain the original joist direction and take less load on the LVL.

If it works with the joist direction you show, however, I like that a lot. Should be a solid system that deflects compatibly together I think. Maybe your joists could be 12" and you could run MEP below.

 

[KootK]

Gotcha. You could probably do the same thing with prefabricated truss girders. 2' is lot of depth to work with.

 

[cal91]

For the sake of simplicity and moving forward I think I'll go with the steel beam, the owner and architect are fine with that anyhow. Thank you all very much for your help and discussion.