Concrete Shell roof structure Kresge Auditorium look so elegant thin-shell structure, one-eighth of a globe growing to an elevation of 50 feet, and sliced away by vertical glass walls so that it comes to earth on only three points. 1200 tons weight of Shell roof structure made from composite concrete with innovative technology. This Concrete Shell roof architecture designed with conical at the edge of roof building, if looked from the top of building this roof structure just like a clam.