cantilever a steel beam from concrete wall

[Structures33]

Hey all - I have a renovation project where I need to support a chunk of concrete up in the ceiling space (don't ask) with a steel beam cantilevered out from an existing 18" thick concrete wall. The load is not too substantial (<1000#/ft on the cantilever) and the cantilever distance is 3'-10"
I'm thinking that the best way to achieve a "fixed" connection for the steel beam is to embed it in the concrete wall. I could design a plate w/ anchors to take the forces and then weld the beam to the plate but I'm just not sure how secure this will be.
Does anyone have any experience w/ a situation like this? If so, what would your recommendation be?
Thanks

 

[PEinVA]

You could just design it like a post. Use Appendix D/similar resource and treat it as if it is a post with a lateral load on it.

That is what we've always done here.

RC
All that is necessary for the triumph of evil is that good men do nothing.
Edmund Burke

 

[Structures33]

If I want to embed the beam, how do I determine how far it needs to be embedded?

 

[jike]

I would probably just have a beam shop welded to an end plate bolted to the wall. Embedding it in the wall would be difficult to form.

 

[faromic80]

Definitely, I would also design it as a cantilevered post and weld it to a base plate bolted to the wall. Use as many bolts /configuration as necessary.

 

[tngolfer]

I agree with Jike. In addition, I would recommend using through-bolts (if you have access to the other side of the wall). You could also use a plate on the back side of the wall if your tension force is very high (although with a normal compression/tension couple it doesn't sound so in this case).

I don't like the embedded beam idea because you are going to run into the wall reinforcement and your connection will be dependent on how well the concrete patch work is.

OT: If it was new construction I would recommend an embed plate.

 

[youngstructural]

It needs to be embedded as far as you need to have:

1. Factored triangular stress distribution assumption be less than your factored concrete capacity. (Be very careful to ensure you are confident of the original concrete design strength & that it's still in very good condition).

2. Deep enough for whatever anchoring you're going to add to be effective. I have never seen a design procedure for a lateral load on something like this, but I would suggest a pull out load of 10% total supported load would be appropriate. Would further suggest not relying on friction between your encastre beam and the concrete as concrete shrinks.

Good luck,

YS

B.Eng (Carleton)
Working in New Zealand, thinking of my snow covered home...

 

[youngstructural]

P.S. I too would prefer another solution as has been suggested by other contributors; I've offered by suggestion only in case the situation makes their (more robust and preferable) solutions impossible.

Regards,

YS

B.Eng (Carleton)
Working in New Zealand, thinking of my snow covered home...

 

[slickdeals]

The other thing which maybe an option is to use a through bolt with plates on both sides, in case you are worried about the concrete strength. This would be similar to many bollard connections on a deck.