Photographs taken in June present our magnificent bascule bridges in raised positions, a rare sight except during boat runs during spring and autumn.
The substructure and part of the superstructure of the DuSable Bridge at Michigan Avenue shows the use of triangulation, the most stable of shapes. Triangles form trusses, brace sidewalks, and also brace the substructure. Underneath, massive counterweghts balance the 2,000-ton leaves during bridge lifts.
Bridges and infrastructures come with a unique language. Rivets, bolts, trusses, triangulation, sidewalk decks, roadway decks, dolphins, fenders, counterweights, wing walls and much more make up part of the lingo you might hear during a bridge inspection.
Bascule bridges come complete with their own special language.
Bridge Inspector’s Training Manual, 70. United States. Public Roads Bureau. United States. Bureau of Public Roads. Bridge Division. U.S. Department of Transportation, Federal Highway Administration, Bureau of Public Roads, 1970. https://books.google.com/books?id=dboCp5jgmuIC&source=gbs_navlinks_s. Length: 200 pages. GOOGLE Books. Accessed 18 June 2020. Also available in print at the Harold Washington Library, Chicago.