Steel Column supported by Beam
Steel Column supported by Beam
(OP)
I have a structural steel column that will be supported directly on a beam flange. I know that this is not an uncommon situation. What do I need to check for? Buckling of the beam web? Required spacing of stiffeners etc? Is there an AISC design guide or similar that shows how to detail that connection? Any guidance would be appreciated.






RE: Steel Column supported by Beam
Check to see if you need a web stiffener
When I am working on a problem, I never think about beauty but when I have finished, if the solution is not beautiful, I know it is wrong.
-R. Buckminster Fuller
RE: Steel Column supported by Beam
RE: Steel Column supported by Beam
The design checks are identical to those that you would do for a truss web/chord joint connection. The base plate is really extraneous when it comes to the design of the supporting member unless you choose to omit the stiffeners.
I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.
RE: Steel Column supported by Beam
RE: Steel Column supported by Beam
When I am working on a problem, I never think about beauty but when I have finished, if the solution is not beautiful, I know it is wrong.
-R. Buckminster Fuller
RE: Steel Column supported by Beam
www.SlideRuleEra.net
www.VacuumTubeEra.net
RE: Steel Column supported by Beam
RE: Steel Column supported by Beam
I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.
RE: Steel Column supported by Beam
RE: Steel Column supported by Beam
If web crippling and yielding is not an issue then technically no stiffeners are required however I tend to just include them at all times.
We generally provide two stiffeners on each side, one under each column flange.
RE: Steel Column supported by Beam
An additional check that you'll need to do is web yielding and crippling on the column web. That will likely work but, if it doesn't, see below for another option that could help to address that.
It's great that this beam is there. It will help to brace and stabilize the whole assembly where that stability is needed most. In an unstiffened scenario, I'm sure that your common framing connection (double angles etc) would help out with web crippling. It might be tough to quantify however. In a stiffened scenario, you'd need to ensure that the connection allowed for the installation of a stiffener of something quite like it at the beam to girder connection.
I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.
RE: Steel Column supported by Beam
KootK, thanks for the sketches. From a design or construction perspective, does it matter which way the column is oriented? I know that this way, the 'N' for my column base plate is not the same 'N' used for the beam web checks.
Why would orienting the columns this way mean that I have to also check web yielding and crippling of the column web? If it's an issue, I think I can turn the columns the other way.
RE: Steel Column supported by Beam
If there's a compelling reason to orient the column web perpendicular to the girder then I wouldn't hesitate to do that. It'll work. If there isn't a compelling reason for that orientation, however, then I would align the column web with the girder for two reasons:
1) That's what's conventionally done in my experience. All else being equal, I trust in the collective wisdom of our profession.
2) If you orient the column web parallel to the beam and use the two pairs of stiffeners that have been mentioned, the entire column cross section (flanges and webs) will bear on stiff supporting elements (beam web and stiffeners). This just feels good to most engineers and obviates the need for any plate yielding and crippling checks in the column.
With the column web parallel to the beam, the uniform compressive stress in the beam can stay uniform as it passes into the beam via direct bearing on the web and stiffeners. With the column web oriented perpendicular to the girder, the compressive stresses will leave the column flanges and flow in a more concentrated fashion through the column web and into the girder web stiffeners. That's what I was getting at with the hatched area in my sketch above.
I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.
RE: Steel Column supported by Beam