If I read the report correctly on the dome posted last night, it said each piece of the dome is structurally dependent on the parts. The roof being one of the key parts. If I understood the report last night.
I haven't read the report, but I'd bet they were saying that each piece of the dome (i.e. the roof) is structurally dependent on the others.
There ARE buildings where the roof is an essential part of the entire structure (your home is a likely example)... but this is not such a structure (at least not from what I can see).