Tank Farm Dike Concrete Liner - Expansion Joints

[horuhe00]

I'm in charge of designing a concrete liner for a fuel tank farm. Base material is clay, the concrete liner is going to be 5 inches with wire mesh plates. I'm thinking of contraction joints every 10 feet and expansion joints at the toe of the dikes and pipe supports.
I'm not sure of the spacing between expansion joints though. I have clay as a base which might buckle the liner with the inherent expansion/contraction of the clay, but I must also make the liner with as few joints as possible to maintain the integrity of the liner in case of a leak and/or fire.
Anybody have any advice?

 

[JedClampett]

I'm not sure what a liner at a fuel tank farm entails. Is it a horizontal slab with sloped walls? We line hopper bottom potable water reservoirs with 8 inch slabs and cast in place walls (poured on the slope) 8 inches thick. We don't use any of that mesh junk, but reinforcing bars spaced at 8 or 12 inches. Our construction joints are spaced at 20 to 30 feet on center with EJ's spaced at over 100 feet, if at all. At the toe of slope we put in a contraction joint with a 9 inch centerbulb waterstop.
If you're worried about clay swelling, ask your Geotechnical Engineer how to mitigate that.
A 5 inch slab with mesh sounds like a dressed up sidewalk.

 

[horuhe00]

It's realy a dressed up sidewalk, the clay being the actual secondary containment. The tank farm's been there for 60 years and the new owners want to save on the maintenance cost by covering all 32 acres with concrete. Go figure.

My question is if expansion/isolation joints would only be needed on the toe of the dike or a minimum spacing between them or none at all?

 

[dik]

Can you do a quick sketch of your proposed perimeter containment?

Dik

 

[msquared48]

"The tank farm's been there for 60 years and the new owners want to save on the maintenance cost by covering all 32 acres with concrete. Go figure."

What about the provision for increased runoff from stormwater? Has the present system been designed for this scenario already?

Mike McCann
MMC Engineering

http://mmcengineering.tripod.com

 

[dik]

Any pre-existing environmental issues?

Dik

 

[horuhe00]

The perimeter containment is an earthen dike with a 1.5:1 slope and a 3 foot walking path on top. The toe of the dike goes stright into the 1.5:1 slope without a gentle transition.
There's no increased runoff since the clay doesn't let the water percolate and the dikes need to get drained after every rain. Anyway, the effluent plant has more than enough capacity since that was the design parameter.