The historic Lake Street Bascule Bridge in downtown Chicago is currently undergoing a massive $138 million rehabilitation project led by the Chicago Department of Transportation (CDOT) and Granite Construction. Originally built in 1916, the 109-year-old double-deck, double-leaf bridge has been fully closed to vehicles and pedestrians since October 2025 to undergo a comprehensive overhaul. The extensive scope of work includes replacing the entire bridge deck system and superstructure, upgrading the mechanical and electrical systems, rehabilitating the substructures, and restoring the historic bridge houses to ensure the infrastructure remains viable for decades to come.
While vehicle traffic has been successfully rerouted to nearby streets like Washington and Madison, Chicago Transit Authority (CTA) rail service on the bridge’s upper deck has managed to continue largely without interruption. However, commuters are preparing for significant upcoming transit adjustments, as the off-site construction of the bridge’s west leaf shifts toward the “float in” phase. To install the new bridge spans, two major 12-day full shutdowns of the CTA Green and Pink lines are scheduled, the first of which is fast approaching for Fall 2026, with the second planned for Spring 2027. The entire infrastructure project is on track to continue through the next year and a half, with a final completion date slated for January 2028.
This bridge rehabilitation is expected to enhance faster movement of goods and people. Also, in another similar undertaking Lunda Construction Company has been awarded the Roberts Street Railroad Bridge Replacement Project contract in Minnesota. The project is valued at $61.9 million and will be completed by 2029.
October 28, 2025
Granite Construction has started work on the long-anticipated rehabilitation of Chicago’s historic Lake Street Bascule Bridge — a $138 million project commissioned by the Chicago Department of Transportation (CDOT). The century-old bridge, which connects the city’s bustling downtown with the Near West Side, will undergo a comprehensive overhaul to improve safety, reliability, and mobility for thousands of daily commuters.
Built in 1916, the Lake Street Bridge serves as a critical transportation link, carrying both vehicular and elevated train traffic across the Chicago River. The rehabilitation project will include the replacement of mechanical and electrical components, structural steel repairs, resurfacing of the bridge deck, and modernization of control systems — all while maintaining the bridge’s original architectural character.
Granite will also upgrade pedestrian and cyclist pathways, aligning the design with Chicago’s Vision Zero plan for safer streets. Work began in September 2025 and is scheduled for completion in late 2027, with most of the construction occurring in carefully phased stages to minimize traffic disruptions.
“Preserving Chicago’s historic infrastructure while preparing it for the future is at the heart of this project,” said a CDOT spokesperson. “The Lake Street Bridge is an iconic part of our city’s skyline and an essential part of our transit system.”
The project also supports local economic development. Granite expects to hire union tradespeople from the Chicago region, contributing to a workforce of over 200 during peak construction.
Once complete, the bridge will offer smoother, safer passage for vehicles, pedestrians, and CTA trains, while ensuring the historic double-deck structure continues to operate efficiently for decades to come.
Additionally, Chicago is pursuing massive infrastructure upgrades, including the expansion of O’Hare International Airport, which is scheduled for completion by 2034.
Factsheet: Lake Street Bridge Rehabilitation
Location: Chicago, Illinois
Total Cost: $138 million
Contractor: Granite Construction
Client: Chicago Department of Transportation (CDOT)
Bridge Type: Double-deck bascule (movable) bridge
Built: 1916
Start Date: September 2025
Estimated Completion: Late 2027
Jobs Created: 200 construction jobs
Key Improvements: Structural repairs, new mechanical systems, deck resurfacing, safety upgrades
Project Team
Project Owner and Lead Agency: Chicago Department of Transportation (CDOT) — Managing the overall funding, municipal planning, and traffic rerouting strategies.
Primary Transit Partner: Chicago Transit Authority (CTA) — Coordinating the upper-deck rail track replacements and the vital 12-day window operations for the Green and Pink lines.
General Contractor and Construction Lead: Granite Construction (NYSE: GVA) — Heading the heavy civil construction, fabricating the new bridge leaves off-site, and executing the critical mechanical and structural overhauls.
Structural Engineering and Design Partner: DB Sterlin Consultants, Inc. — Responsible for structural engineering design elements, including the upper-level floor beams for the CTA tracks, fixed-span sidewalk steel and concrete, new bridge houses, and exterior stairs.
Specialist Subcontractors and Consultants:
- Wiss, Janney, Elstner Associates (WJE): Brought on for advanced structural load testing and finite element modeling to analyze the bridge’s concrete pit structure and support capacity.
- LS Contracting Group, Inc.: Handling the complex, delicate concrete masonry restoration of the historic bridge houses to maintain their original 1916 architectural character.
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