Originally Posted by The Grand Architect
Not for a long time. Like RoadCruiser said, the underground work must be completed before the "ribs' are installed. The ribs are attached and supported by the underground steel.
One step at a time.
No, while half of the ribs will get attached to B1 ceiling and half to the B2 ceiling, the two steel arches surrounding the skylight will be the responsible to carry and spread every load of the ribs, until that happens they'll have to be guyed.