We are doing some minor modifications to this hollow corrugated concrete structural system. The corrugations are used as ducts... so at the center of each of the corrugations, there is a penetration in the supporting concrete beam.
Span is consistent with a folded plate... main rfg at top and bottom 'points' with adjacent plate providing lateral support (like a series of arches). Matter of taking a look at the last panel to see how it is braced.
What does it look like from above? Does the roof follow the same ridge/valley pattern as the ceiling? Or is it flat roof, with a flat structural slab over the entire system? I have seen both.
Page 29 of the Dec 2009 Concrete International pictures a precast system like this. Prestressed, hollow box girders carrying mechanical services inside.