Bearing Plates for Tank Columns 1

[JES1812]

We are in the process of repairing a storage tank. We added a secondary floor and trimmed the columns to suit. So we have new floor plate and new column bearing plates. API 653 has rules regarding minimum overlap for patches on a tank floor. A question came up re: overlap of the bearing plates, and whether we need to adhere to the same minimum overlap criteria. Since this is new floor plate and new bearing plates it seems reasonable to look to the API 650 code, but this code does not address this issue (as far as I can tell).
Is there guidance for overlap of column bearing plates with new construction?

 

[JStephen]

See Section 9.10.3.1 in API-653.
I would take this to include wear plates or base plates welded to the tank bottom, but not loose bearing plates that are not welded to the tank bottom.

 

[IFRs]

Not related to your OP but if you used sand under the new bottom, over time it may migrate and allow the column to settle, affecting the roof structure. Think of walking on the beach and stepping on a pile of sand. Ringwall foundations have hoop rebar for this purpose - to contain the soil under the bottom. Again, not responding to your question but one of my pet peeves...