Heat Treat Pre-engineered building column 1

[ahunt]

We have a building that has been hit by an excavator. The web of the building wide flange column has been buckled, and the flange displaced out of it's plane.

Anyone ever use heat straightening to fix something like this? AISC claims it's more of an art than science. I'm not sure if this is the technique to try, or just cut the column and weld one a new section.

A.

 

[youngstructural]

There are accepted methods for heat straigtening steel members, however AISC is quite right to call it an art. The real concerns are the speed at which the member is heated, the temperature at rebending, the rate of cooling, and also you need to be very certain that no cracking had occurred.

Not something I have ever tackled, however as long as this isn't a moment resisting frame member, or another "harder" working member type (or zone of a typical member) I would have no problem trying it; With instructions I was confident in and understood completely.

To that end, go have a look at:

http://isddc.dot.gov/OLPFiles/FHWA/009569.pdf

The file is very big, but comes from:

http://www.fhwa.dot.gov/bridge/heat.htm

Looks like something that might be quite useful to you.

Good luck!

YS

B.Eng (Carleton)
Working in New Zealand, thinking of my snow covered home...

 

[hokie66]

I think it is more trouble than it is worth. I would just prop the structure, cut out the bent part, and weld in a prefabricated replacement section. I have seen the bottom section of columns rotated 90 degrees by impact, and always just cut out and rebuilt. May want to consider some protection if this is a high traffic area for heavy equipment.

 

[Zhuge]

agree with hokie66 here. temperature treatment after heating would be really difficult to be done.

 

[gerhardl]

Also agreeing, apart from difficulties doing the job, how could you ensure that the material had the right metallic structure and necessary strength?

 

[SperlingPE]

Agree - replace the damaged section

 

[ahunt]

Thanks for all the help. Replacement seems to be the only real way to go.


A

 

[dik]

Pre-eng buildings don't have a lot of redundancy... In addition, the repair will likely void any warranty... you might want to talk to the building supplier.

Dik

 

[271828]

dik is right. Try to get with the original manufacturer, or at least someone who's very familiar with how MBs are designed. Replacing it correctly might be easier said than done.

 

[DaveVikingPE]

I agree. I don't recall anything from the MBNA manuals discussing repairs. Metal Building Systems are a lot trickier than one would think and the moment (pun intended) you change something you are now responsibile for the building's behavior.

 

[271828]

Dave, we now know who you have your credit card with, LOL. I've typed that before too.

I'll add that MB guys will take a look at situations like this. I heard a while back that Star looks at retrofit, etc. applications from time to time. Those guys are top notch, in my experience, when it comes to really doing things "right."

I've worked on a lot of both, and it is truly amazing how much more analysis goes into these than a typical steel bldg.

 

[dicksewerrat]

If the footing and footing connections weren't damaged, I'd go to the original manufacturer for a replacement of the entire column.

Richard A. Cornelius, P.E.

http://WWW.amlinereast.com

 

[civilperson]

Overkill to replace column. Straighten with heat and then add plates for any additional strength you need to sleep good.

 

[youngstructural]

I honestly love being corrected by more senior engineers. Mental note: File under "When to say no/When to go with a simple, non-technical, solution".

Good luck,

YS

B.Eng (Carleton)
Working in New Zealand, thinking of my snow covered home...

 

[dik]

Rookie... your comments are OK for an existing 'old' building... but for a new one under construction, there is no manner of repairing a damaged column, except as undertaken by the building supplier... else they will void the warranty and the general is on the hook... if acceptable.

Dik

 

[hokie66]

Who said anything about this being a new building? An excavator can hit an old building, and skinny metal buildings have been around for a long time.

 

[dik]

My mistake... dik