JimKSF
Structural
- Apr 21, 2008
- 9
Hi everyone and thank you in advance, I'm not sure if this question can even be answered.
We often run across steel piles in the marine environment that are experiencing corrosion in the tidal and splash zones. In some cases this has caused the (typically) epoxy coating to rupture or completely fall away, and in some cases the corrosion is evident beneath the intact epoxy coating because of visible blisters.
On most jobs we have commercial divers (professional engineer divers usually) do a full inpsection of the piles below the high water line and this includes removing the delaminated material and electronically measuring the remaining steel thickness on at least a percentage of the piles. (ASCE 101 calls for Level III, this, inspection on 5% of steel piles).
What I was wondering was whether there was a relationship between the height of a blister and the corrosponding amount of section loss that that would be the result of. I could start having the divers measure the height of the blisters or delamination before cleaning and see if I can develop a line (or curve) myself, but I was wondering if anyone has run across any papers addressing this.
It could come in very handy in preliminary investigations to be able to tell an owner that they have 3/4" blisters on their 1/2" wall thickness pipe pile and this will probably be proven to show a section loss of 1/16", 1/8", etc. We would still go through with the Level III inspection on some percentage of the piles, but if we could rapidly determine a likely section loss without having to clean, use NDT, and recoat the piles we could get a more thorough understanding of the scope of the problem much quicker.
There may be too many variables, but I was just wondering if anyone had seen anything on this.
We often run across steel piles in the marine environment that are experiencing corrosion in the tidal and splash zones. In some cases this has caused the (typically) epoxy coating to rupture or completely fall away, and in some cases the corrosion is evident beneath the intact epoxy coating because of visible blisters.
On most jobs we have commercial divers (professional engineer divers usually) do a full inpsection of the piles below the high water line and this includes removing the delaminated material and electronically measuring the remaining steel thickness on at least a percentage of the piles. (ASCE 101 calls for Level III, this, inspection on 5% of steel piles).
What I was wondering was whether there was a relationship between the height of a blister and the corrosponding amount of section loss that that would be the result of. I could start having the divers measure the height of the blisters or delamination before cleaning and see if I can develop a line (or curve) myself, but I was wondering if anyone has run across any papers addressing this.
It could come in very handy in preliminary investigations to be able to tell an owner that they have 3/4" blisters on their 1/2" wall thickness pipe pile and this will probably be proven to show a section loss of 1/16", 1/8", etc. We would still go through with the Level III inspection on some percentage of the piles, but if we could rapidly determine a likely section loss without having to clean, use NDT, and recoat the piles we could get a more thorough understanding of the scope of the problem much quicker.
There may be too many variables, but I was just wondering if anyone had seen anything on this.
