Bridges

Bridges are such ubiquitous features of the built environment that we cross most of them barely acknowledging their presence. Certain bridges, however, command attention: for their utility facilitating travel from here to there; for their size, setting, beauty, or historical associations. Ordinary or spellbinding, every bridge is a response to a problem--the spanning of a river or other obstacle, solved more or less elegantly. This visual sourcebook surveys American bridges from coast to coast in terms of four fundamental structural types (beam, arch, truss, and suspension) and the special category of movable bridges (swing, lift, and bascule) showing how similar structural ideas have been addressed by different designers, refined over time, and rendered in various building materials. A special feature is A Call for Preservation of the American bridge engineering heritage by Eric DeLony, formerly chief of the Historic American Engineering Record, National Park Service.