connecting perpendicular lower steel beam to upper steel beam without post.

[lubos1984]

Good morning everyone,

I did an inspection where client was complaining about sagging floors. Turns out they had 2x8 joist spanning over 15'6"! Not sure how this passed inspection.
In any case the joists need to be supported.

The client does not want any additional posts. There is also a dropped return air you can see on the left which is why i'm proposing the below.
My question:

If I install a flush beam (left to right). On left side bearing on foundation wall, on right side bearing on top of the existing steel beam.
From there install a perpendicular dropped beam extending from the dropped beam in the back and towards the front of the house bearing on foundation wall.
Is there a way to connect the dropped beam to the flush beam without a post using brackets with welding ? I haven't come across a connection like this so was wondering if anyone can provide some recommendations?

Thanks!

 

[jayrod12]

Maybe a strap that connects to each side of the flush beam and is hung underneath the dropped beam. Not sure if the capacity will work out for you, but it may.

 

[milkshakelake]

Assuming you use W shapes, you can bolt the dropped beam top flange to the bottom flange of the flush beam. Besides typical checks, you'd check the beams for prying action. Stiffeners are probably not necessary but I like to throw them in for good measure.

 

[Enable]

I agree that bolts through the flanges would do the trick. But I must be missing something as I don't understand the point of the flush beam. Is there a specific line load between the joists at that location you are going to pickup? I cant imagine you'd need an extra support for the dropped beam because you could just size it for the span, and the parallel dropped beam existing appears to span the same distance.

The flush beam will also need to be field spliced or you'll have to have the mechanical contractor re&re the HVAC / plumbing to get the beam into place. Also, just placing a beam will leave the sag intact. If you want to remove it you'll need to jack up the floor and that is something that needs to be discussed with the owner given the possibility of existing finishes being damaged, etc.

CWB (W47.1) Div 1 Fabricator
Temporary Works Design

https://www.enable-inc.com/

 

[jayrod12]

The OP can clarify better, but the way I understand it is, he needs to cut down the floor joist spans by installing a dropped beam running the length of the house. a beam to span that entire direction without an interior support would be gigantic. Therefore he's looking at installing a flush beam to support the dropped beam to keep the sizing reasonable.

I also assumed they were talking wood instead of steel beams. That's where my strap idea was coming from.

Hopefully they can shed some further light.

Edit: I see the title indicating steel beams. So therefore I was wrong. I agree with the above posters that just flange bolts and appropriate stiffeners would be more than adequate.

 

[Enable]

I guess my confusion jayrod12 is that if the beam isn't sized to span from post to foundation wall, then the flush beam doesn't really do much as a support because the end bears on another steel beam that (seems to) itself spans that distance. I mean, unless you run the numbers and decide that the 6" (??) beam we are bearing on has excess capacity. But if it did, why couldn't we make an 8" (??) beam work for the full length?

Perhaps the plan is to put a post / footing underneath the existing beam at the pickup point. That would work.

I suppose it also depends on if the idea is to remove the sag or just stop future sagging.

CWB (W47.1) Div 1 Fabricator
Temporary Works Design

https://www.enable-inc.com/

 

[jayrod12]

Interesting point. I wonder what those two 6x6 wood posts are doing beside the staircase.

 

[lubos1984]

apologies for the confusion.
some clarifications:
- the proposed beams are steel
- the flush beam is required to avoid placing an intermediate column for the proposed dropped beam. since then span would be over 25'.
- the flush beam (W6) needs to be flush because a return air duct is in the way at the left support. The right support would sit at the beam at stairway (there is actually a post on the right side but you can't see form the pic)
- the proposed dropped beam would thus have three supports 1. existing steel beam 2. support form the W6 flush beam 3. front foundation wall.
Thank you for your comments

 

[XR250]

... If you are trying to jack up the existing floor, you will likely have to kerf the joists at the beam location in order for them to actually sorta straighten