Crude oil tank over old concrete foundation

API 650 is your go to specification here and Appendix B has lots of recommendations for foundations.

I don't think there is any "prohibition" which implies legislation, but it doesn't seem like a good idea unless you still have all the calculations for the foundations and the foundations themselves need to be checked for any settlement.

There is a lot of leeway for engineering judgement here, but you need to check your own company procedures and philosophies on reuse of things like foundations or the client if you're building it for someone else.

Most standards tell you how to do something, they don't list all the things that you can't or shouldn't do, so proving a negative sometimes gets quite difficult.

For the cost difference I would dig it up and renew it myself, but that's up to you. Your risk is foundation failure once you've built your tank. No one will thank you at that point for saving 5% of the cost of the tank if it needs to be torn down and re-built.

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More good advice from LittleInch !!! ... I agree ...

MJCronin
Sr. Process Engineer

In discussions about putting new bottoms in tanks, it has been mentioned that various contaminants in an existing sand pad may have negative effects on a new bottom. So even if structurally sound, you may still want to replace the upper few inches of sand pad.

True. Any leakage in the part won't be good news.

You may not be able to do inspection until the old tank is removed then it might cause issues if you then decide to build a new foundation.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

Dear Mr. LittleInch

I am very thankful for your help

Best regards

I think with the existing foundation, you do not want to create a 'hard' point in the support of the tank. This could have unintended and objectionable consequences.

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So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik