Possible to have, Structurally, A Dome Garage first floor living on the second floor?
Yes. Dome of a Home and Eye of the Storm are two examples where the bottom floor is the garage and completely open. The main living floors are suspended via cables anchored from the dome shell. There are no bearing walls in the garage spaces.
The purpose of this design is to allow storm surge, during hurricanes, to flow through the garage, without damaging the living spaces.