12-04-2016, 02:35 PM
I did not cast a concrete base for my tank, merely screeded an level spot on an ample bed of sand. I do wonder what would happen in an earthquake. I do somewhat regret not putting the tank on a reinforced concrete base. I suspect the primary failure mode would be having the base of the steel ring pinch the vinyl liner or having the liner bulge out from underneath as the ring tilted. I am not so worried about the steel ring splitting down the side as they are supposedly strong enough and usually they rip because overflowing water has caused rust.