[Porsche-O-Phile]

Yea, in a seismic situation I think the lip of the pool would help to restrain lateral movement of the joists, but I don't particularly like the bases of those columns. Those pre-cast bell footings seem pretty cheesy to me. They're not really spreading out the loads much and effectively you're point-loading the slab/pool bottom where the columns bear on it. If it were me I'd core through the bottom and sink an honest-to-goodness footing or pile in there. If the earth starts moving up and down (as opposed to side-to-side) those things can literally "hop" off their foundations and collapse. Other than that I like the concept overall. It certainly can work and it will create an interesting space when done, but I agree - the thing that's most concerning me is the vertical support columns. They just look kind of skinny and not very strong at their bases - certainly not a lot of lateral stability there.