Rigid Frame Column w/ Boxed-In Flange
Rigid Frame Column w/ Boxed-In Flange
(OP)
I encountered something this week I had not run into in nearly 40 years of practice. Please refer to the attached file for the column section specifics. This is from an old (1968) industrial metal building frame. The columns have the “boxed-in” angles added to the inside column flange only. The reinforcing angles extend to the column haunches, but do not follow the bottom flanges of the rafter beams; i.e.: they are column flange supplements only.
Has anyone ever encountered these before? What is their specific purpose (I have some theories, but that is all they are at the moment.)? I have not yet had an opportunity to contact the manufacturer for their information (it’s Sunday!).
Any and all experiential insights are appreciated. Thanks.
Has anyone ever encountered these before? What is their specific purpose (I have some theories, but that is all they are at the moment.)? I have not yet had an opportunity to contact the manufacturer for their information (it’s Sunday!).

Any and all experiential insights are appreciated. Thanks.
Thaidavid






RE: Rigid Frame Column w/ Boxed-In Flange
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RE: Rigid Frame Column w/ Boxed-In Flange
Here's the attachment.
Thaidavid
RE: Rigid Frame Column w/ Boxed-In Flange
BA
RE: Rigid Frame Column w/ Boxed-In Flange
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: Rigid Frame Column w/ Boxed-In Flange
Another idea is that the angles were added just to reinforce the columns against impact. Industrial buildings take a lot of abuse, particularly columns near doors.
RE: Rigid Frame Column w/ Boxed-In Flange
The remainder of the structure is oddly typical of what you would see everyday - except for this. From a structural standpoint, I don't understand why they would reinforce just one flange as they did, since it makes the column very eccentric, and it no longer matches the rafter profile. My thinking was along the same lines as yours - this was simple "armoring" to reinforce the flange against forklift impacts. However, for what ever good it did them, the bottoms of the columns still look like hell anyway. These columns have no girts to brace the compression flanges when in reverse bending, so that could have been a reason also, as you suggested. However, that seems an expensive way to get additional allowable compressive stress and column height, when simply going to heavier flange plates would have worked just as well - and without the expense of all those welds!
Thanks for your inputs thus far, guys.
Thaidavid
RE: Rigid Frame Column w/ Boxed-In Flange
It makes the column asymmetric but probably more concentric with the applied load.
From the outside, it's often hard to say what makes sense with a manufactured product. Maybe their fabrication process didn't suit flanges as wide/thick as they needed to be. Maybe they just had some of these columns laying around the yard from a job that went south.
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: Rigid Frame Column w/ Boxed-In Flange
Thaidavid
RE: Rigid Frame Column w/ Boxed-In Flange
RE: Rigid Frame Column w/ Boxed-In Flange
Now I have seen this type of detail printed in TWO places!
Dave
Thaidavid