Steel Beam to Concrete Column Moment Frame Connections

[RFreund]

I have a situation where we have steel roof beams connected to concrete columns and we need to create a rigid frame. The loads are fairly light and EQ is SDC B. I thought about doing end-plate moment connections to the column, but I have a few concerns.
Major concerns are:
1. Developing the vertical column bars at the top of the column. If I can develop these bars (maybe hook/hairpin) based the bottom flange of the beams, I should be "ok", right? I thought about possible welding hooked bars to the side plates almost like a corbel design, but maybe that is unnecessary.
2. Constructability - Having welded end plates doesn't leave much tolerance for length. Maybe I cast in plates and use top/bottom plates to weld to the beams.

Sketch with a couple ideas below. Any feedback is appreciated.

 

[canwesteng]

I think you need to do some kind of strut and tie layout to prove it works. For length you can just grout between the end plate and the column to avoid all the field welding. I would think something like this, with a rebar terminator, or you could extend the column and add a hook.

 

[KootK]

Getting predictable capacity out of such a connection will be difficult. What prevents you from doing something like this? Are there concrete beams running the other way?

 

[KootK]

With both of the original details, I have concern that you'll deliver your top flange compression forces in a concentrated fashion at the top of the column that that will cause the top of the column to crack off pretty much no matter what you do for reinforcement.

 

[bones206]

Watch out for potential thermal effects with highly restrained connections: thread507-508732

 

[GC_Hopi]

Check the PCI details

 

[RFreund]

Getting predictable capacity out of such a connection will be difficult. What prevents you from doing something like this? Are there concrete beams running the other way?

This was my first idea, but it just doesn't seem as stiff. I guess that's the way to go.

Appreciate all the input.

 

[KootK]

This was my first idea, but it just doesn't seem as stiff.

With the DBA's right below the column stub flanges, I would think that it would be the most stiff of the available options since it avoids the two primary sources of flexibility in this situation:

1) Load transfer via steel plates in flexure and;

2) Load transfer via local concrete compression bearing.

Basically the Holy Grail of connection detailing.

 

[KootK]

My biggest concerns with a lot of these details are really:

1) Ability to get quality concrete into the column and;

2) Ability to accommodate construction tolerances.

In that spirit, another proposal... You'd have to ensure that the bolts are detailed in such a way to achieve the requisite shear transfer.

 

[RFreund]

This is actually really good too. Love when you push your ideas to the limit.
In some cases there is a steel beam perpendicular that also needs to be a fixed connection, so that muddy's the water, but otherwise, this is another feasible configuration.