State Street bridge, Chicago visit

This bridge is among the newer of Chicago's deck truss bascule bridges with a 1949 construction date...The bridge is an example of the unique Chicago design which raised the position of the deck truss up just far enough so that the top chord is above the deck like a pony truss, where it can act as a guardrail and also increase both the clearance under the bridge and the streamlined aesthetics of the bridge. This design is known as the railing height truss...

Chicago visit for IIDA and Neocon

Today Chicago boasts somewhere over 40 movable bridges. At least 20 of these are in the downtown area. During Chicago's boating season, which runs from April 15 through November 15, over 52,000 boats pass through the Chicago River, and the bridges are opened close to 30,000 times a year.