How to repair a HSS steel column in a warehouse 2

[mlevario99]

Hi, I have a client that ask me to look at a warehouse he is renting. Some of the columns have been hit by a forklift, some of them have a hole due to the impact. Other columns have a bent on one of the faces of the tube. Has anyone done any repair on something similar, the columns are 8X8X1/4. Do you guys cut the damage area and use plates welded to the existing columns?

Thanks for your help.

 

[SteelPE]

I've seen engineers who will encase the column in concrete.... Helps with the damage and with protection in the future

 

[TehMightyEngineer]

Yep cast them into concrete, easiest and cheapest way to protect the columns and simultaneously help with the damaged sections.

Maine EIT, Civil/Structural.

 

[paddingtongreen]

Usually, I found such columns to be slender and as such, I could usually write off local damage, since normal compressive stresses rule locally rather than the reduced values used for slender column design. The effect on the column such as reduced capacity can be checked by iterative means, by hand calc or by computer.

Using a reduced stress instead of using a reduced column capacity has always annoyed me

Michael.
"Science adjusts its views based on what's observed. Faith is the denial of observation so that belief can be preserved." ~ Tim Minchin

 

[Ron]

Repair/replace the column first, then encase in concrete or install bollards.

To repair the column, shore the area, straighten the bent section or cut out and replace. Check the connections above to see if compromised and for badly damaged columns, check welds for all members that are supported by that column....impact damage can crack weld at joist-to-beam or beam-to-column connections. Check all connections for displacement and make sure that the roof surface slope is restored to drain properly, if low slope or "flat" roof.

If you splice a column, you should use a complete penetration weld or provide reinforcing plates on partial penetration welds.

 

[dik]

Add temporary support and cut out or repair the offending areas and using plate, reinforce the columns. Some columns have a higher Fy than the plate material, and also the damage isn't normally in an area affected by slenderness so you may be able to use a greater design capacity for the steel.

If the new operation does not require protection, then encasing in comcrete may cause some problems with operation and takes up floor space. I've used 'elephant feet' for numerous projects but generally only where forklift is used.

Dik

 

[SteelPE]

"elephant feet" I can guess what this is but could you elaborate?

 

[msquared48]

Renta Elephant:

http://havetrunkwilltravel.com/

Mike McCann
MMC Engineering

 

[ztengguy]

I think some bigger HSS sizes bigger can be sliced down middle and patched onto the existing column with pretty good success. Then put up a cone with caution sign, or encase in concrete. Be sure to dowel into slab, so you get a bit more shear resistance too.

 

[msquared48]

http://cdn2.elephantplasterboard.co.nz/U-EnTCB-columns.pdf

Mike McCann
MMC Engineering

 

[paddingtongreen]

The different answers exhibit the difference in point of view. The last half dozen that I looked at were abandoned mill buildings from back in the days when they used a mix of trussed columns, "I" shapes and wide flanges. In each case, they were looking to use the floor for sorting recycling materials without using the building structure. If it required money spent they would move on to try another. They just wanted to know that the roof would not fall on them.

Michael.
"Science adjusts its views based on what's observed. Faith is the denial of observation so that belief can be preserved." ~ Tim Minchin

 

[dik]

Elephant feet are just large circular cylinders cast at the bottom of columns for protection against moving traffic... they work well, but are intrusive on floor plans that don't require them.

Dik