i need ideas how to expand the room...

i need ideas how to expand the rooms out on the outside of the ring the ring is 83by83 on the outside (the purple ring) and it goes down to the under levels whihc have rooms, but before that its the top of those rooms where u can see the builds, i want to expand out onto the outter bit of the rings with big pillars and rooms that are grand for the size of the open space to the top of the dome, the outter room carved out is 113by113 and to the ceiling before the dome starts is 61 high maybe we can have two floors between those blocks