Steel beam bear 4 feet on a masonry wall at end

[jdengos]

Instead of adding a steel column at one end, I want the beam to bear 4 feet long on a 8 inch masonry bearing wall. the bearing plate will be 7"x48"x5/8" with anchor studs embedded into the wall, 1/2" grout below plate, w18x46 weld on top of bearing plate. the load at this end is 22 kips, I want to make the bearing long enough, so the wall footing can take the load, soil condition is unknow, assumed 3ksf.

I know it looks crazy, and have never seen this before, anything wrong with the design?

 

[jayrod12]

Yes, I can't see a situation where the bulk of the load doesn't end up in the first few inches of bearing on the wall. At a plate of that thickness, there's no way it's going to spread the load over the 48".

If you are trying to ensure proper load spread at the bottom of the masonry wall, why not size an appropriate bearing plate, 7"x8"x5/8" or whatever you need to not overload your masonry at the bearing point. Locate the plate back from the edge of the wall enough to get the masonry wall to spread the load out as it goes down.

Most masonry codes have guidance for load spread angles.

 

[jdengos]

I did the bearing plate design, it doesn't even require a bearing plate per calcs, beam flange is good enough.
but I think typical bearing plate calcs doesn't consider localized load spread. so I need the bearing plate to spread the load on brick.

Actually it's brick wall. Brick wall load pressure is small if the plate can spread the load. I need it long only for the footing bearing purpose.

 

[JAE]

The bearing plate will not spread the load on the wall foundations - the wall does that.
The bearing plate will only make the concentrated beam load spread out over a very limited area to avoid masonry bearing failures at the top of the wall.

So making the plate long for the footing is not correct.

Check out Eng-Tips Forum's Policies here:
faq731-376

 

[jayrod12]

So put a small plate, say 7x7, and again put it back from the edge of the wall to avoid a stress riser right at the edge and then let the wall spread the load down.

 

[msquared48]

If you use the smaller bearing plate as suggested, set the plate 3 feet back.
Depending on the height of the wall, that should spread out the load to the footing to 6 feet or more.

Do not place grout under the beam between the edge of the plate and the end of the wall to allow the beam to deflect and the point of bearing to remain at the bearing plate.

Mike McCann, PE, SE (WA)

 

[Ron247]

I agree with the other posts in 'set a small plate back from the edge".

I think if you do what you are talking about, while attempting to spread the load, you are somewhat creating a fixed-end on your beam. If you do not tie-down your bend end, it rotates freely up and you are no different than had you not lapped it so far. If you tie it down to force bearing to occur, you have fixed-ended it to a large degree. Clamp 4' of a 14' beam between 2 heavy walls and it will act fixed ended.

 

[jdengos]

Thank you all for the great input! I am using 12x7x3/4 plate now, and off from edge of wall.

But I'm used to grouting the pocket, maybe I should just brick enclose it, and keep void under beam.

 

[msquared48]

Do solid grout and reinforce the vertical CMU wall cells directly under the plate all the way to the foundation, and from the plate, do not place drypack or grout between the bottom of the beam and the top of the CMU.

Mike McCann, PE, SE (WA)

 

[jdengos]

Thanks Mike
Grout solid, but keep void under beam.