how do you reduce the capacity based on corrosion?

[delagina]

Some of the members but most importantly the Anchor bolts are corroded.

This structure is sort of abandoned for sometime where they removed all the equipments but now they now want to use it again and add another level.

Grating is actually heavily corroded but that doesnt concern me.
I am concerned with some anchor bolts.

Also there is water leaking at the upper level and this set of anchor bolts are always wet and is now corroded. The column is corroded also but not that bad.

I wanted to post pics but cannot. Company Policy is strict.

 

[JedClampett]

I personally would be very conservative in evaluating this. If the bolt is noticeably corroded, I would completely ignore its capacity. For one, it will be almost impossible to determine how much bolt is left without cutting into it. Plus, the corrosion might be oriented such that there are stress concentrations at the interface and fracture is likely at lower stresses.
If that means that the whole structure is unable to sustain loads, that is what I would say. If it needs major repairs to get it up to code, sometimes we have to convey bad news.

 

[JedClampett]

That's what I would do. You might want to get a little mirror and check the back side of the "good" bolts.
Plus, I would state that whatever I can't see (below the concrete surface) is of unknown quality.

 

[frv]

It may be an optical illusion, but the other two bolts seem to have corroded at the base plate interface.

 

[delagina]

should i request to have water leak fixed as soon as possible to prevent further corrosion? structure currently not in use so nobody cares, i guess.

other structures in use are just as old but well maintained (minimal corrosion).

 

[kelowna]

In the great scheme of things, replacing a few anchor bolts is a negligible expense on the refurbishment of a structure. I suggest it is considered as an alternative to estimating (or guessing) remaining capacity.

 

[delagina]

kelowna, thanks..

i have no experience about replacing anchor bolts. i have done adding new anchor bolts.

so how is replacing done? can i just say remove these anchor bolts then replace new hilti bolts?

 

[rscassar]

I don't know how you can cut the existing bolts and replace with new chemical anchors. The new chemical anchors will need to be offset from the existing which would require modifications to the existing baseplate.

How are you going to treat the corrosion at the base of the column and is the structure located in a corrosive environment.

 

[kelowna]

Sorry delagina, I should have been more specific, you are right, of course, much easier to add new anchor bolts than to replace existing ones.

 

[BAretired]

The middle bolt seems to be more corroded than the others. Why would that be? It might help to sandblast the steel to get a better look, then measure the circumference of each bolt. If it seems okay, then protect the steel with galvicon paint or similar coating capable of resisting the chemical environment present in the building.

There isn't much you can do about the part you can't see.

BA

 

[delagina]

thanks.

it's probably because it's abandoned for sometime and it was not galvanized. also if you look at the way it was moment connected to the base plate (no plate washer) the oversize holes caused dirt and water to go inside.

anyway i'll just add more anchor bolts and have the base plate repainted.

any more inputs and advice will be appreciated.

 

[csd72]

For replacement of bolts I would suggest you look at the AISC webinar 'steel fixes', it goes into a variety of ways that you can replace bolts.

 

[rscassar]

Is there any non-destructive testing equipment which can be used to determine how much the embedded items have corroded?

 

[a2mfk]

I'm with kikflip, I would be worried about what I CAN'T see in the concrete... Don't stick your neck out too far on this one.