By Divi Logan, Photographer and Author
These are among the best of over 380 photographs taken October 19, 2019, during boat runs and bridge lifts along the Main Branch of the Chicago River. Photographs of the structure follow the bridge’s title.
Lake Shore/ Outer Drive Bridge. Conditions for the lift included glare from waterways and buildings along the river (lesson takeaway will be to purchase a high-quality circular polarizing filter and also challenge myself to try more manual focus fine-tuning). Structures shown include the deck truss web, inspectors, inspection equipment, bridge houses with tenders inside, and elements of bridge substructures and superstructures. As each bridge lift, the boats, collected between bridges, sail under the massive spans, some weighing 2,500 tons.
As the morning was on the chilly side I went for a fresh, hot coffee. By the time I emerged the Columbus Drive Bridge was already up and glassy glare was evident, so I took a few pictures of it and then positioned for the raising of the DuSable Bridge at Michigan Avenue. This best of the Columbus Drive pictures is the south leaf.
The DuSable Bridge at Michigan Avenue is a magnificent double-deck, double-leaf bascule with four bridge tender’s houses; you can see their bridge operators. During each lift, crews of CDOT inspectors staff each bridge to ensure everything runs efficiently.
The Wabash Avenue Bridge was open before the DuSable Bridge closed.
Features of bascule bridges include double-leaf spans, navigation lights, floor cantilever beams for sidewalks, elaborate floor bracing systems with lateral crossings, and in the case of many seen here, pony truss superstructures.
Divi Logan. Chicago, October 22, 2019.