American Scientist

Civil engineering structures are usually designed to remain as they are built, where they are built. Thus a bridge becomes a fixed crossing of a river, and a tall building a familiar beacon in a skyline. There are exceptions, of course, as when the bascule span of London's Tower Bridge opens to allow tall ships to pass, or when the brise soleil of the new addition to the Milwaukee Art Museum unfolds to shade its atrium from the sun. Such exceptions fall into the category of deployable structures, those that have more than a single appropriate configuration: open and closed, folded and unfolded, stored and deployed.