Observation boxes at Chicago's Sears Tower, which opened last week as part of an extensive renovation of the tower's observation deck, are among the most recent, and more outlandish, projects that use glass as load-bearing elements. But all glass structures have at least a bit of daring about them, as if they are giving a defiant answer to the question: You can't do that with glass, can you?
You can. Engineers, architects and fabricators, aided by materials scientists and software designers, are building soaring facades, arching canopies and delicate cubes, footbridges and staircases, almost entirely of glass.
Full story from New York Times.