The Illinois River Bridge was originally built as four 154-foot fixed through truss spans. About 1932, Span 2 was converted to a vertical lift span and the adjacent spans fitted with lifting towers, counterweights, and an electro-mechanical operating system, providing a 120-foot clear opening. Under the provisions of the “Truman-Hobbs Act” of 1940, the USCG is funding alteration of the bridge to provide a 300-foot marine opening. The replacement vertical lift span will be 348 feet long and have a maximum lift vertical clearance of 56 feet.

Modjeski and Masters, Inc. has performed the following engineering services:

Phase I: Project Outline and Design Criteria Collection of relevant data, evaluation of alternatives, establishment of design criteria, cost estimates and preparation of a project report.

Phase II: Final Design Final design with preparation of contract plans and specifications and apportionment of costs.

Phase III: Construction Engineering Office support and field monitoring of construction of the bridge alteration.