Tank Foundation, Steel Ring wall

[wilburfhh]

I am trying to repair the bottom of a tank (30 ft dia x 27 ft tall, API 653) but it has some foundation problems so we need to fix it. The owner does not want to use concrete ring wall because it is expensive or slab or crushed stone. My foreman told me that he has seen steel ring walls on tanks before, somewhere in West Texas, back in the 70's. He says that as long as the steel plate keeps the sand in place, it shouldn’t be much different.
Is there such a thing as a Steel Ring Wall? Has anyone seen it? Do you know if there is a paper or a book about that topic?
Thanks for all your help.

 

[bimr]

It is not really a ring wall. It is just a steel bottom tank. These are made with overlapping seams on the bottom. The edge of the tank is welded to the side wall. The tanks were typically constructed on top of an oiled sand base.

A ring wall tank may not have a bottom of steel, it may have a concrete bottom.

 

[JedClampett]

It's a very common installation in cases where the owner wants to save a few bucks. I would just design it for the same circumferential forces as the reinforcing in a ring wall (A=.00052xHxDxdxg) where H is the height in feet, D is the diameter in feet, d is the plate height in feet(I'd use at least 8 inches) and g is the specific gravity of the liquid. This limits the stess to 20,000 psi.
I don't have a reference for this. I'm positive someone else will.

 

[Unotec]

We put steel rings about 30cm tall and about 30cm larger diameter than the tanks. Then we fill them with gravel and set the tank on top.
Assuming the compaction of the tank farm is correct and that you did it when the ground was dry and not frozen, your tank will not move much if any at all.
The tank farm top layer is also gravel over sand over liner

<<A good friend will bail you out of jail, but a true friend
will be sitting beside you saying ” Damn that was fun!” - Unknown>>

 

[JStephen]

Usually called a retainer ring, not a ringwall. Just a cheaper way to build a foundation.