Steel Exposed to Fire

[TRAK.Structural]

Looking for folks with experience evaluating steel structures that have been exposed to fire/heat. I've read some reference material/articles about general evaluation processes but its a bit of a mixed bag. Some say more or less that if it hasn't deformed than its generally ok. Others say that coupons should be taken for testing. Is there more recent info out there that is generally accepted that offers an evaluation procedure?

Additionally, when looking for deformation, is the standard of care just a visual inspection or are we talking about Lidar scanning to detect miniscule variations?

For reference, I've been asked if I want to evaluate a local auto body shop that had a recent fire. Its a couple bay PEMB structure so nothing super crazy.

 

[ANE91]

We do this a lot. You end up paying less attention to the steel and more attention to everything else. You can get a good spatial idea of how hot the fire burned by examining all involved materials. Cable jacketing melts at one temperature; concrete can turn pink at another. There have been times we used LiDAR, yes. It just depends on what you’re seeing out there and how critical the member is in terms of redundancy. Most recently, we were setting up to scan after a major fire in a trash warehouse when the thing collapsed. (We wanted to monitor ongoing movement.) Haven’t had to take coupons yet. The steel is usually spaghetti by the time I get out there, so who cares what the material properties are at that point.

I’ve read something or other about how a fire can accelerate corrosion, but I defer to the corrosion experts for the veracity of that claim. I’ve only ever seen coating damage.

 

[mfgenggear]

Wait is this illegal thermal treatment?

 

[dik]

Spagetti beams look so neat... If the structure has not deformed, it is likely OK. Take some coupons and do some tests to confirm.