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Re: Twisted column

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Drew,

       As I see it there are at least two alternatives.

Plan A:
Either load test the column or find some fancy computerized (finite element, maybe?) to assess the adequacy. Either may be expensive and you may still have to carry out a repair.

Plan B:
Do a simple hand analysis to assess how much "safety margin" there is; and, if you are not satisfied with the results do a repair using the money you saved by not following Plan A. You said it was a pre- manufactured building, therefore, it probably has very little "safety margin". If so a repair may well be required.

My suggested repair would be to box it in using 1/4" or 3/8" plate (stitch welding should be OK but that's up to you) and fill it with concrete. The resulting column should be many times stronger and more torsionally rigid and be much more resistant to "dents and dings" from future impacts.

       Hope this helps.

Regards,

H. Daryl Richardson

----- Original Message ----- From: "Drew Morris" <dmorris(--nospam--at)bbfm.com>
To: <seaint-seaosc(--nospam--at)mail-list.com>
Sent: Wednesday, May 15, 2013 9:04 PM
Subject: [SEAINT-SEAOSC] Twisted column

I was called to a repair shop where a steel column had been hit. It is an interior built-up column for a pre-manufactured building, about 9" depth and 9" wide flanges made from 3/8 plate. Looking at the field measurements, I don't think the flanges arrived at the job site parallel.

The column has apparently been hit a few times. The column is about 18 feet high and at mid-height there is a frame welded to one flange that supports a lubricating hose reel and at about 3 feet above the floor, there is a steel table of 1 inch plate steel that has been fitted around the column on all sides and welded to the flanges. It hangs out about 2 feet from the flange. At the hose reel level, one can see the distance between the flanges increase from 9" to 9 5/8" and corresponding decrease on the other side. The variation exceeds the tolerances in AISC Table 1-22. There are no sharp kinks in the flanges, just a slow change in depth. Looking at the base, the column has been rotated a few degrees.

It appears that I have a column that has been slightly twisted and has suffered local bending around the web to make the flanges non-parallel.

Truncated 335 characters in the previous message to save energy.

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