Tank foundation

[Moersleutel]

We have a concrete tank foundation that is out of the flatness tolerance specified by API 650.

What remedies are commonly used? We are considering a sand and bitumen layer to bring the flatness into spec, any comments?

Further, due to the location of the site and availability of bitumen, would it be possible to use old machine oil instead of bitumen for this solution?

Any advise would be appreciated!

 

[IFRs]

Is this a newly poured foundation? Is it a slab or ring wall?

 

[JStephen]

Under the tank shell, grout would normally be used for minor adjustments.

If it's an existing tank, see API-653.

 

[IFRs]

If this is a new slab, I have found it practical to grind the high spots.

 

[Stl63]

Typically a grout ring is used around the perimeter (under the shell wall) and then a sand or fiberboard layer under neath the floor. Being that your foundation is not level, sand would be best. Clean dry sand is the only specifications here. Using machine oil in the sand is not an eco-friendly method. Search for this on other threads, it's been covered several times.
Also remember, depending on the unlevel condition, raising the tank elevation will affect pipe connections.