US-based construction company Granite has started rehabilitation work on the historic Lake Street Bascule bridge in Chicago, Illinois.
The rehabilitation project is valued at approximately $138m and was awarded to the company by the Chicago Department of Transportation (CDOT).
The project, which received its funding from CDOT, is included in Granite’s first quarter committed and awarded projects.
The Lake Street bridge, built in 1916, serves as a critical route for vehicles, pedestrians, and Chicago Transit Authority (CTA) buses on its lower deck, while the upper deck carries CTA’s Green and Pink Line trains.
The scope of the work involves a complete replacement of the double-decked trunnion bascule bridge over the Chicago River.
In addition to reconstructing the main structure, Granite will carry out substructure rehabilitation, replace CTA tracks on the upper level, and upgrade both mechanical and electrical systems for the movable sections of the bridge.
The project will also restore the historic bridge houses, retaining their original architectural features.
Construction methods for this project include building the new bridge leaves off-site.
Each leaf will be moved into position during separate “float-in” periods, requiring two scheduled service outages for the CTA Green and Pink Lines.
These outages are planned for autumn 2026 and spring 2027.
Throughout the construction phase, at least one bridge leaf will remain operational at all times to comply with federal and US Coast Guard requirements.
Granite regional operations vice president Michael Punches said: “This collaboration with CDOT to rehabilitate one of Chicago’s century-old, iconic movable bridges underscores Granite’s strategic commitment to the Chicago market.
“By leveraging our specialised expertise in movable bridge rehabilitation, we continue to deliver lasting value to the city’s infrastructure.”
Work on the project began this month, with completion anticipated in December 2027.
In July 2025, Granite obtained a $111m contract from the Utah Department of Transportation to carry out major infrastructure improvements in Salt Lake City.
