Repair Method - structural column 5

[razanvd]

A 10x10x0.25 HSS Building column with 35'high ceiling got a forlift impact about 2" from the bottom floor which caused an approximately 6" dia dent (caved in) on one face while adjacent face bulged about 1" out, see attachment. Could some one advise me the best possible method to fix this? Thanks

 

[MiketheEngineer]

Obviously replacement is the best and likely the most expensive solution.

Check the numbers - maybe it was designed to only 30 or 50% of maximum. It might be OK as is.

Or weld plates around it to re-inforce the column.

Might want to add barriers around columns.....

 

[DaveAtkins]

I agree with Mike--I would do a finite element analysis of this portion of the column. I bet it will work--you are near the bottom of the column, so overall column buckling is not an issue. When you don't consider overall column buckling, the column capacity goes way up.

DaveAtkins

 

[JLNJ]

Do a simple analysis whereby you set the bottom (or keeping it symmetrical the top AND bottom) few feet of the column to the reduced stiffness. I bet you'll find that the column works OK as it. You still might want to install a fix so that the NEXT whack doesn't take it out.

 

[frv]

Tell the fork lift guy to ram it from the other side to see if it evens out

 

[civilperson]

Weld some jacking ears to the face above the damage, jack up to relieve load on bottom, cut out damaged fraction and weld back replacement piece for dented area. Add bollards for collision protection on all sides.

 

[SteelPE]

The damage to your column is minor compared to mine.

http://www.eng-tips.com/viewthread.cfm?qid=215858&page=1

In this particular building, we ended up replacing the column shown. Other columns that were not damaged as bad were encased in concrete and reinforcing (down to the footing). The concrete extended up few feet above beyond the damage.

 

[rb1957]

i wonder if your airport rd is anywhere near my airport rd (in case i should be worried) ???

 

[DWHA]

Have you considered incasing the column in concrete? You could drill a couple of holes through the column and add thru bolts to develope the concrete.

 

[Tomfh]

I'd use a fine tuning hammer to flatten the bulge, and then weld on some plates.

 

[honat]

I would do one of two things.
1) I would detail a pedestal made from 4-L4x4 angle iron on top, 2-1/2" thick plates with holes for 4-3/4" HIT anchors on bottom and 4-HSS3x3x1/4 legs above the plates. Weld the angles of this entire assembly to the column just above the dented portion of the column. Then fasten it to the foundation using the HIT anchors. To prevent future damage I will recommand that bolards be installed.

2) I will simply encase the bottom of this column and others in the area in protective concrete with minimum reinforcing. I am sure the damage is such that the remaining section is quite capable of carrying any of the original design load!

 

[Teguci]

I don't think I'd want to mess around with the buckled side of the column without unloading the column. Therefore, I'd side plate the column and box the dent with 3/8" (bent?)plate (including top plate).

I'd give two justifications:
1. Its already been hit, might get hit again
2. Didn't want to do a more expensive option.

If the client is interested in selling the building in the near future, this would not be the right answer. However, that answer would be to unload the column, cut out the damage and replace in kind.

 

[csd72]

Teguci,

your proposed fix sounds fine in principle.

Just do some numbers on it to make sure your decisions are based on science and not pure judgement.

 

[msquared48]

Try drilling a couple of small holes a couple feet above the damage and filling the tube with non-shrink grout to that level. This should stabalize the section. Weldint additional plates to the outside would helop too.

As an alternative, you could install plastic explosives in all the columns to be set off upon impact. Great way to catch the offenders here.

Mike McCann
MMC Engineering

 

[dik]

Push the bulge in and weld a cover plate over the indent. Damage is near the base and will likely have little effect on a slender column as far as buckling strength.

Dik