Connecting a Steel Beam to a Concrete Column - Unique Connection 1

[zjr5273]

Hello,

I am researching a means of connecting a cantilever steel beam to the vertical face of a proposed concrete column. The attachment of the steel beam to the concrete column will occur at a much later date. I am avoiding threaded anchor rods as the projection of the threaded rod from the face of the concrete column is undesirable. I am also avoiding post installed anchors for the risk of damaging the column reinforcement in addition to lower allowable strengths compared to cast anchor rods. I was hoping to locate the invert to a threaded anchor rod with a threaded coupler of sorts that attaches to the formwork and casts into the concrete leaving a threaded plug for which to install bolts into. Has anyone come across or used something like this before?

Thanks,

rzoppa

 

[bones206]

Something like EM-Bolt embed plates?

https://em-bolt.com/

 

[jjl317]

Depending on the loads, precast spot inserts could be an option (i.e. Dayton Superior F57 style), or even Halfen channel embeds.

 

[gte447f]

Why not a flush embed plate with headed stud anchors welded to the back? The beam/endplate or whatever can then be welded to the embed plate later, right?

 

[KootK]

First inclination would have been an embed plate as gte447f proposed. It's a minor thing but my preference in this would be to replace the top row of studs with hooked deformed bar anchors. As far as tolerances go, you could make the future connection with discrete flange and web connector plates to allow the construction team to tweak the yaw and pitch of the beam.

 

[phamENG]

gte - I seem to recall reading something where the thermal stresses can potentially damage the concrete. Maybe I'm making it up, though? Don't recall exactly. Probably depends on the size of what you're welding. If you need to pump a bunch of heat in to weld a 3/4" flange to a 1" embed plate, it could get interesting. Probably not an issue on a little W6 that'll be used to hang a bathroom sign.

 

[zjr5273]

gte447f - Thank you for the suggesting. It was considered prior to my post but the future connection happens repeated and the labor for a field welder would be too great.

 

[gte447f]

phamENG, I don't know if heat from welding is an issue with the concrete or not. Surely not for smallish fixtures, since this sort of thing is pretty common, but maybe it could be an issue with large welds. I'm not aware of any concerns, but my experience has been with pretty smallish fixtures welded to embed plates.

 

[KootK]

Maybe I'm making it up, though?

That may have been me. I once transferred a heavy steel column to the end of a concrete wall this way and it took an embed about the size of man. The heat of welding did spall the concrete around the embed due to thermal expansion and, for future work, we started breaking plates up into smaller junks (better for handling anyhow). That said, modest sized embeds that receive welds are ubiquitous and don't generally seem to cause problems.

It was considered prior to my post but the future connection happens repeated and the labor for a field welder would be too great.

I'd have a conversation with your contractor about tolerances. I would expect that:

a) a welded solution will often be better for tolerances and;

b) the savings in having easy tolerance adjustment would offset the cost of welding.

This is why most renovation work goes welding. And, in many respects, this will resemble renovation work.

 

[gte447f]

rzoppa, after having a look at the em-bolt product linked upthread by bones206, I reckon that's about exactly what you were looking for, right? I wasn't aware of this product, but I must admit, at first glance it looks pretty neat.

 

[structSU10]

We had them install a compressible filler similar to a sill gasket all around embedded plates to be welded to help mitigate potential thermal expansion issues in the past.

 

[bones206]

I spec'd em-bolts on a project last year that is in the shop drawing phase now. The contractor wants to substitute regular embed plates because they really want to field weld the shear tabs for whatever reason. (I assume they have little confidence in their ability to meet tolerances). At the same time, on another project, another GC requested em-bolts by name as a substitute for the regular embed plates we specified.

I mentioned em-bolt plates in a thread a while back (thread507-485541), so it probably looks like I am on their marketing team at this point. But they do seem like a useful product.

 

[HTURKAK]

If i were in your shoes, i would consider future through bolt connection. I would leave sleeve pipes casted with column similar to the item 2.6 Steel Beam to Concrete Wall ( but for moment connection) of the following doc .










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