The Jefferson Street and McDonough Street Bridges in Joliet, Illinois provide access across the Des Plaines River. They are among the busiest bridges along the Des Plaines River, averaging 28 openings and closings a day. IDOT initiated this project due to concerns over the effect of the large numbers of bridge openings on the mechanical and electrical components.

Both structures are Scherzer double-leaf rolling lift bascule bridges built in the early 1930's. The rolling lift bascule movement is caused by two rack and pinion set which, along with counterweights, roll each leaf along tracks.

Modjeski and Masters, Inc. provided the following engineering services for the condition inspection and summary report of the structure:

Phase I

• Inspection of the electrical components

• Inspection of the mechanical components

• Strain Gage Balancing Study

Phase II

• Maintenance Recommendations and Report