Largest Inverted Shell Houses Two Theaters

A meeting center in Albany, New York, has such a complex shape that it took months just to design its surface mathematically. Perched on a pedestal, it is nearly elliptical in plan. From the side, it looks like a giant devilled egg. The shell is 200 ft wide, 280 ft long and 80 ft deep. It is of reinforced concrete and has a posttensioned ring girder to minimize deformations. It was designed three times; first, by analyzing a series of slices, then by a method of similar shells to check the first design. Later, to cut construction time, it was redesigned using finite elements to incorporate a steel truss-and-deck roof in place of the original concrete slab-and-girder design. The structure took seven years to build.