Anchor bolts with fire damage 1

[AZPE]

I have a town home project that was burned down by an arson after it was fully framed. I haven't been to the site yet but I know that they are going to ask. They will want to know if the anchor bolts are going to be salvagable. What issues would you expect from bolts that have been in a residential fire? I wouldn't imagine that the heat was very great, or at least not hot enough to alter the steel properties. I would guess that the bolts would be okay

Any ideas/thoughts/help would be appreciated.

 

[Lion06]

Wouldn't it be pretty easy (and inexpensive) to just drill and epoxy some new anchor bolts in? If the framing has been burned installation shouldn't be a problem either. It won't cost that much and you won't have to worry about whether the anchor bolts are ok.

 

[FSS]

Just load test a representative sample and go from there.

 

[sennafan]

AZPE

Our firm has investigated hundreds of fires over the years and I have worked on jobs where anchor bolts have been tested to verify capacity. We have rarely if ever seen anchor bolts themselves compromised by fire. Testing 1" diameter hold-down anchors at one site also showed no loss of strength in the steel. Demolition and cleanup is the usual cause of anchor bolt problems due to damaging the surrounding concrete. We have even tested badly bent bolts that were subsequently straightened and always found them to be strong enough.

The economics of slow demo/cleanup vs new epoxy anchors is usually the determining factor.

If the surrounding concrete is badly spalled or has turned pinkish color, then you need to look at whether the damaged concrete needs to be replaced.

sennafan

 

[AZPE]

Thank you sennafan,

Do you have any reports or reference material on the subject? Just wondering, but if the concrete has turned a pinkish color, what would be your next step? How exactly would you determine if the damaged concrete needs to be replaced? Why does the concrete turn pinkish?

Sorry for my inquisitive post but I finally got someone that knows something, not just speculating. Don't get me wrong, engineering is all about using the knowledge that we have about materials and the physical world to come to conclusions regarding situations that we haven't experienced, but it's nice to hear from someone that doesn't need to do that because they have been on the other side.

Thanks again for any information.