Slab Thickness For Water Taank

[okstate06]

I have to pour a slab for a 12,000 gal watertank which is 12 feet in diameter. What would my thickness have to be to avoid cracks in the slab? This will happen in Oklahoma and the soil content is mostly sandstone and clay. What I wanted to do was pour the slab and footings all at once by digging the outer perimeter extra deep. Lastly, what size rebar would I need and how close shouls I put them together?
Thanks for all of your help.

 

[civilperson]

A 9" thick slab, (f'c=3500 psi), with uniform subgrade capable of 2000 psf bearing with Woven Wire Reinforcement of 6" x 6", W8.9 x W8.9 will probably suffice for your use.