The $240 million bridge spanning the Hoover Dam has garnered one of the nation's top civil engineering awards. Officials say Monday that the Mike O'Callaghan-Pat Tillman Memorial Bridge won the Outstanding Civil Engineering Achievement award last week from the American Society of Civil Engineers. The 1,900-foot-long bridge built by the Federal Highway Administration is part of a four-lane bypass that reroutes traffic around the dam. Construction began in 2005, and the bridge officially opened in 2010.