Asphalt Base Under Tank 1

[dik]

We have a 100' dia steel tank sitting on an asphalt base. The asphalt mix design that has been submitted is a good quality mix and ample for the loading.

Are there any special API requirements that the asphalt has to meet?

Thanks, Dik

 

[Ron]

dik.. My concern would be that even small amounts of petroleum product leakage will affect the asphalt.

 

[dhengr]

Dik:
I second what Ron said, leakage or spillage. Asphalt, to what avail, except increasing the floor base cost? It’s just a slightly harder (flatter?) working surface during tank construction. Otherwise, it isn’t worth much more than its base below or any other compacted base that you might use. You certainly can’t count on the asphalt alone out under the tank wall, as a ring beam or foundation, can you?

 

[dik]

I agree... The tanks do not hold petroleum products. They hold other liquid, not injurous to asphalt. Partly for containment. Design by others. I just got the question.

Dik

 

[dik]

Should have added...tank and supports to API Specs.

Dik

 

[Ron]

dik...if you have no potential solvent activity, then my next concern would be creep under the load; however, there is probably enough flexibility in that size tank to handle a reasonable differential. If there are internal columns with a roof structure, you might want to check the potential creep load under those, particularly if a floating roof.

 

[dik]

Creep shouldn't be an issue from a load point of view. I've done a few tanks, but they have been contained in a perimeter foundation wall with compacted granular fill and sand bedding. This is also contained in a similar fashion. I've also used waterproof membranes for this purpose.

Dik

 

[dik]

Steve has brought up a good point regarding cathodic protection. I'm going to suggest they revisit the use of an asphalt base.

Dik