Tank Settlement after Moving

[kalluna]

Hi,
We have a situation where a 20 yr old tank was moved in order to replace liner. We had an API 653 on tank in old location in 2003 and it showed several locations (3 stations) with higher than acceptable edge settlement. This summer the tank was moved. We did hydrotest, and an API inspection. The tank has edge settlement now in only one location and not too much of it(2.4 inches versus 2 inch allowable. API report says to replace that one floor plate as it was under strain. We are wondering if this strain and continued deflection/settlement was caused by the move but we really have no way to find out, do we? We did not have an API done just before moving the tank in spring-perhaps we should have?

 

[apiguy]

Why not excavate the small area and jack the tank in that location ?

The APIGUY....

 

[FrCivEng]

Jacking is long and expensive, only for important foundation repair or replacement

When replacing the plate in the bulged area, you must repair the backfill underneath the plate, for instance by removing the existing up to 0,20 m deep and replacing by sand + 4 % cement compacted backfill prio to reinstall the new plate.

You should have perform an API 653 - Appendix B settlement outside survey on the tank in service in order to check the compliance of tank foundation in order to repair it (whether necessary) during the shut down period

 

[kalluna]

Yes we did do an API 653 appendix B inspection during shut down (when tank was moved into new location); the inspection results are those to which I referred above-indicating that the floor plate should be replaced as per appendix B4.2 .

 

[jimmoore]

I agree with apiguy ... and it is not really a big process to jack a tank. Especially if it is a small area. A few bottle jacks and some wood cribbing is all you need. Won't take long either. If your only talking one plate then thats only about a 15' span of over all jacking.

Now if you need to do the whole foundation then yes it is expensive.

 

[FrCivEng]

It seems more simple and cheaper to replace 1 plate than to locally jack the tank ; ask for a quotation ... !