longest floating bridges in the world
How to Build the Worldâs Longest Floating Bridge. Hulking engineering projects built with 230,000 tons of concrete generally donât float. Washington state, however, knows a little about how to make so much mass actually buoyant. Washington owns the four longest floating bridges in the world. The longest, State Route 520, connects Seattle to points east over Lake Washington, which dips to 214 feet deep.