15000 g Emergency Water Storage Tank

Hello all, I am a parent volunteer involve in planning to build a (wood) shed and maintain an emergency water storage tank (Polyethylene Plastic; 92" dia x 60" h; 15,000 gallons & approx. 13,000 lbs when full) at my son's elementary school outdoor playground area. We are looking at different exterior locations for the tank that is safe and out of way where the shed will keep the tank from the weather and other physical damage of an everyday play yard. Most of the areas in question are currently concrete or asphalt paving (play yard material?) and the shed has not been designed.

I have some design experience but not an engineer. My thought is that with all that weight of the water, a structurally reinforced concrete foundation may be necessary for the tank? If so, is it necessary to secure the tank to the foundation? I would like to make sure that this is not going to roll off in an event of an earthquake (we're in N. California, a very likely event). Is there anything else I should be concern about structurally? I realize we may need to consult a structural engineer but any help or suggestion would be greatly appreciated!

-Catherine

 

I think you might have meant 1500 gallons? As 15000 would be closer to 125,000 lbs.

 

I am sure someone here can come up with some dandy construction tips for your shelter.
However, considering that you are responsible for the safety and well being of other people's children you really need some professional guidance on this.

Also, in addition to the construction of the building you need to ensure the tank and water itself meets your local health standards.

 

I suspect the project will have to go through the local school board bureaucracy as well.

 

Tanks like that are quite often just sat on the ground. Almost any concrete pad should easily handle the weight as long as the tank has a flat bottom that evenly spreads out the weight. Now, if you are trying to elevate the tank off the ground all bets are off. You will probably need an Professional Engineer.

Here's my math:
Water is about 8.35 pounds per gallon so the 13'000 pound weight and tank dimensions point to 1'500 gallons. The tank is 96" diameter which has an area of about 7'238 square inches. Divide the 13'000 pound weight by the tanks bottom area of 7'238 square inches and you get a ground pressure of about 1.8 pounds per square inch (psi). The average mid sized man has a ground pressure of about 8 psi to keep things in perspective.