Steel Beam to residential exterior wall connection

[Brobocop]

Looking for clarity on a long span wide flange beam connection to a wood frame exterior wall with a flush ceiling finish (attached very professional sketch lol). Beam will need to rest above the wall top plates. FYI, there will be truss joists 16" O.C. framing into the beam laterally.

Is there a best practice connection here? I thought to maybe lag bolt the bottom flange into the top wall plate on either side of web?

Also, is there a target TL deflection limit y'all like to use? I've seen L/600 for LL, but maybe L/460 or L/500 for TL?

I appreciate the help.

 

[BAretired]

I would prefer a steel post supporting the steel beam, but it can be done either way.
The contractor might prefer a timber beam which he can install when he is ready.
Deflection limits are specified in the code...usually L/360 for live load and L/240 for total load.

 

[Tomfh]

Yes fix it to the top plate. Make sure your nailing plate is properly bolted to the beam too, and joists likewise fastened to the plate. That way the whole floor plate including beam is locked together.

 

[Brobocop]

I would prefer a steel post supporting the steel beam, but it can be done either way.
The contractor might prefer a timber beam which he can install when he is ready.
Deflection limits are specified in the code...usually L/360 for live load and L/240 for total load.

My only issue is one of the two beams is 21'. If I do L/240 for total load, that's 1.05"... I assume there would be a noticeable sag or "bulge" in the center of the ceiling. I'm trying to tighten up my tolerance, so there is minimal deflection for the drywall.

 

[Brobocop]

Yes fix it to the top plate. Make sure your nailing plate is properly bolted to the beam too, and joists likewise fastened to the plate. That way the whole floor plate including beam is locked together.

Perfect. Thanks.

 

[Eng16080]

My typical detail for this sort of condition is to support the steel beam directly with a wood post. I'll have a couple vertical steel tabs welded to the bottom of the beam with holes for 1/2" though bolts. I usually have a 1/4" plate welded to the end of the beam as well.

With that said, I think your detail may be fine. You should check bearing perpendicular to grain where the beam is in contact with the wall top plate. I would expect that could be an issue if the loads are high.

For a longer span beam, I often limit total deflection to an absolute limit, like 3/4". It really depends on how the space is going to be used though. If this is for a super high end home, you may want to go less.

 

[cliff234]

Is this beam supporting any bearding wall loads? Since deflection is a serviceability limit state (versus a strength limit state), I think you could consider using a reasonable live load that may be less than the reduced live load computed per ASCE 7 for the purpose of checking deflection. I would also add stiffener plates at the end of the beam where it bears on the wall (as recommended in figure 2-1 in the 16th edition AISC Steel Manual).

 

[XR250]

Honestly, I rarely make a connection to the wall for a flush beam. Where is it going to go? The floor system will hold it in place.

 

[lexpatrie]

SDC A requires a positive connection for 1% of the load, doesn't it?

Bearing onto the perpendicular to grain wpod top plate is going to make that top plate pretty unhappy, a steel bearing plate could be used to reduce crushing, or land on the end grain of a post which probably interrupts your diaphragm chord.

 

[jerseyshore]

99.99% of the time I use a steel column with a steel beam, but in the two cases that I specified wood posts, it's always a PSL column (no perp to grain plate in between) with tab plates & bolts similar to what Eng mentioned above. I know some inspectors around here won't pass a steel beam to wood post detail without some sort of angle/ tab plate bolted connection.

 

[XR250]

SDC A requires a positive connection for 1% of the load, doesn't it?

Single family dwellings in our area are exempt from seismic. Again, where is it going to go? The floor diaphragm perimeter connections will dwarf a few lag bolts into a top plate. If the beam is being used as a collector, I would make a positive connection.

Bearing onto the perpendicular to grain wpod top plate is going to make that top plate pretty unhappy, a steel bearing plate could be used to reduce crushing, or land on the end grain of a post which probably interrupts your diaphragm chord.

Depends on the load and bearing area. I always check that.