The Mile Long Bridge project began in 2019 and included the construction of two new wider bridge structures. The three-year project cost $500 million and contained multiple phases. It was innovative, safe, collaborative, and its impact to one of the country’s most congested metropolitan regions can’t be overstated.
Carrying up to 150,000 vehicles a day, the Mile Long Bridge is a vital piece of infrastructure to Chicago, its southwest suburbs, and the Central Tri-State Tollway (Interstate-294), and this project’s success has earned first place on our list of Top 10 Bridges of 2023.
“The Mile Long Bridge Project represents a major milestone and achievement in the delivery of the broader Central Tri-State Tollway (I-294) Project, a $4 billion project that is reconstructing and widening 22 miles of roadway on the most heavily traveled corridor in the 294-mile Tollway system," said Illinois Tollway Executive Director Cassaundra Rouse. "The Mile Long Bridge demonstrates engineering ingenuity in its design, minimizing impacts to the waterways, railways and roads below, as well as innovation in construction techniques to deliver a new and improved bridge back to our customers on time and within budget.”
Led by Illinois Tollway and HDR, the project included two new side-by-side, 4,800 foot structures to increase capacity from four lanes to five. The new bridges widened a 22-mile corridor of I-294. They also relieved congestion and reconstructed an existing piece of infrastructure to meet current and future traffic demands.
Crews worked in tight spaces on the Mile Long Bridge. They built the southbound structure between the new northbound bridge and the original southbound bridge. The distance between the new bridges ranged from a few feet to 30 feet, which proved to be a challenge.
A gantry system solved the problem. It allowed crews to move and install steel bridge beams on the southbound bridge. This eliminated the need for cranes on barges and helped the contractor overcome site-access constraints.
This project included some of the largest steel and concrete beams on an Illinois Tollway project, with some weighing up to 115 tons.
Over 500 concrete beams traveled more than 100 miles from Wisconsin, and the steel beams were transported from Kentucky. These beams were massive: the concrete beams measuring nearly 8-feet tall and up to 187-feet long. The steel beams measured up to 10-feet tall, with segments ranging in length from 57-feet to 134-feet long.
These beams were unique. The design was based on the California wide-flange beam shape to accommodate the railway underneath the structure. These beams were considered the best choice for the project in terms of efficiency, stability, and constructability.
Communication was crucial to a project this big. A series of coordination efforts between multiple communities, environmental agencies, utilities, railroads, and local agencies made the challenge greater.
Coordination also took place between the Illinois Tollway, 69 engineering firms, and 109 construction firms to ensure this project met its end goal, on time and within budget.
Crews got to work on this project and finished in late 2022. The team, consisting of FH Paschen, Walsh Construction, Lochner, HDR, Quigg, and the Illinois Tollway ensured that the structure was safe for travel, and opened up this heavily traveled bridge to the public.
Despite the challenges, the Mile Long Bridge is up and running, proving that no matter how big the challenges are, crews can get the job done when they work together. The team worked hard to ensure that this structure would be open for motorists for years to come. RB
Project: Mile Long Bridge
Location: City of Countryside, Village of Hodgkins, Village of Justice, Village of Willow Springs, Village of Burr Ridge and Lyons Township
Owners: Illinois Tollway
Designer: Lochner/HDR/Quigg
Contractor: FH Paschen (prime, northbound), Walsh Construction Co. (prime, southbound)
Cost: $500 million
Length: 4,800 feet
Completion Date: October 2022
