I have a client that has a very large number of dents in the floor of a storage tank due to stalactites falling. Most if not all of the dents fail the API-653 Annex B, B.3.3 criteria for internal bottom settlements or bulges. There are no leaks and the roof geometry that created areas for the stalactites has been corrected.

I'm having a hard time condemning this floor to repair because in my opinion the dents do not fit the criteria for Annex B, they haven't been created due to settlement and the foundation has more than likely been compressed and is still providing support. We were able to get a few UT readings in the centers of some of the larger dents and the thicknesses are still nominal (there is some thinning at the edges of the dents due to forming of course).

I've also looked at section 8 in API-579 but that also doesn't seem to apply.

Any thoughts ? (possibly an FEA analysis provided I can get detailed enough dent profiles then check to see if the plates are over stressed ?)....with almost 200 dents it may be cheaper to just repair the floor.