Granite Construction has kicked off a $138 million rehabilitation of the century-old Lake Street Bascule Bridge in downtown Chicago — a structure recognized as the world’s first double-deck trunnion bascule bridge. The project, awarded by the Chicago Department of Transportation, marks a major modernization effort for one of the city’s most critical transportation assets.
Built in 1916, the bridge spans the Chicago River and supports multiple modes of transit. Its lower deck is used by vehicles, pedestrians and CTA bus routes, while the upper deck carries CTA’s Green and Pink Line trains — making it a vital, everyday connector for commuters and visitors.
The California-based contractor will fully replace the double-leaf span to extend its lifespan and improve safety and mobility. The work includes replacing CTA rail tracks on the upper level and upgrading the bridge’s mechanical and electrical systems, along with substructure repairs, according to the release.
A major element of the project involves offsite construction:
the new bridge leaves will be assembled away from the river and then transported in a “float-in” operation involving barge delivery. Those installations will require two 12-day CTA service outages — one in Fall 2026 and another in Spring 2027 — to minimize commuter disruptions while keeping the river channel active for marine traffic.
To preserve the engineering heritage of the 109-year-old landmark, Granite will also restore the historic bridge houses, ensuring their architectural character remains intact even as internal systems are modernized.
“This collaboration with CDOT to rehabilitate one of Chicago’s century-old, iconic movable bridges underscores Granite’s strategic commitment to the Chicago market,” said Michael Punches, vice president of regional operations for Granite, in the release. “By leveraging our specialized expertise in movable bridge rehabilitation, we continue to deliver lasting value to the City’s infrastructure.”
The project aligns with Granite’s strategic shift away from megaprojects in recent years, focusing more on mid-sized infrastructure work that offers faster delivery timelines and lower financial risk. The contractor has emphasized growth in public, DOT-driven projects, fueled by federal dollars from the Infrastructure Investment and Jobs Act.
Granite’s strong performance in public markets has also supported a wave of M&A activity, helping the company increase its backlog and expand its presence across key regions — including Chicago, where major river crossing upgrades remain a priority for local officials.
Construction began in October 2025 and is set to wrap up by December 2027 — positioning the bridge for another century of service in the heart of the Windy City.
Originally reported by Matthew Thibault in Construction Dive.
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