“The existing design of the interchange between Interstate 74 and Interstate 57 is antiquated and does not allow efficient flow of traffic at today’s speeds,” said Kenneth Crawford, a Project Implementation Engineer for IDOT. “Further, the use of reverse curves is a safety concern. The current configuration was the cause of several truck roll-overs in the recent past.”
Besides being outdated, the design “no longer meets current traffic volumes and demands and has experienced operational issues due to deficient geometric features,” according to the project page on IDOT’s website. The interchange is considered a critical freight and travel juncture and has an average daily traffic of nearly 29,000. Freight trucks compose 22 percent of the traffic.
The reconstruction is expected to improve safety at this location. IDOT has tried other options, including placing a friction surface on the existing ramps, lowering the speed limit, and adding speed display signs to alert the traveling public, however issues continued to occur.
“The proposed work includes construction of two new bridges on the eastbound to southbound ramp, one new bridge on the eastbound to northbound ramp, one new bridge on the westbound to southbound ramp, two new bridges on the westbound to northbound ramp, box culvert removal and replacements, earthwork, HMA and PCC paving, traffic control and protection, removals, drainage improvements, temporary erosion control, seeding, MSE and retaining wall construction, safety improvements, pavement markings, signing, LED lighting, and various other items required to complete the planned improvements,” Crawford said.
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Ultimately, the project includes the construction of seven bridges and a mechanically stabilized earth (MSE) wall.
The first challenge on every project is getting work done, while maintaining traffic flow. As per the contract, the team is allowed to have nightly lane closures on I-57 and I-74. Therefore, a significant chunk of work has taken place at night.
Workspace is limited in the area, as there have been four concurrent related projects around the interchange reconstruction. The projects involve replacing bridges, ramp reconstruction, and pavement reconstruction. Two of the projects were comparatively small, and they were completed in 2021. However, the other two projects are significant and ongoing.
Because multiple projects are happening in the same area, which impacts traffic flow and the flow of materials to the work site, teams need to communicate and coordinate schedules. This is essential to allow each project to progress as planned.
“The second contract to reconstruct Interstate 74 and Interstate 57 was awarded eight months after the original contract to construct the new interchange ramps, and the second contract intended to utilize completed ramps from the original contract as detour routes, however those ramps were not complete,” Crawford said. “Accommodations were made to ensure both contracts’ construction could continue. Ramp closures were allowed to permit the construction of both contracts simultaneously.”
The team constructed embankments that included 40 feet of fill material. The amount of time to complete settlement was variable and prohibited construction of the new structures, according to Crawford.
Because settlement varied, the project schedule was impacted, and progress did not proceed as planned. Soil borings were completed at the embankment areas that allowed the geotechnical engineers to include estimated lengths of time to complete the settlement. Ultimately, the settlement was unpredictable.
“The original contract to construct the ramps included several interim completion dates for cast-in-place box culverts and bridge piers to ensure they were completed prior to the start of the second contract to reconstruct Interstate 74 and Interstate 57 to make sure construction was not in the way of rebuilding the two interstates,” Crawford said.
Adjustments were made to allow certain ramps to be closed prior to the replacement ramps’ completion so construction on the new ramps and Interstate 74 could advance. Slip forming bridge parapet walls will be allowed if an acceptable test parapet can be completed. Staging adjustments were made to accelerate the completion of ramps required to be used as detours for other ramps, helping the project to stay on schedule.
The team has utilized some innovative materials and construction methods during their work on the project.
“There are several jack and borings of proposed pipes under the existing interstates to limit the number of closures that would result from trenching across the pavements,” Crawford said. “The reinforcement bars used in the concrete superstructure for the two 1,700-foot-long flyover ramps are stainless steel in lieu of epoxy-coated steel to increase the service life of the structures from 50 to 100 years. Additionally, the structural steel is metalized to increase the length of time the coatings will last to avoid exposure to the traveling public to maintain the structures.”
IDOT is paying acceleration for two ramps to be completed sooner. They are critical for detours to allow closures of existing ramps so the proposed ramps can be constructed.
The construction costs for the project were just over $90 million, while the budget for all the projects in and around the I-57/74 interchange is just below $252 million. The project is on budget.
The project is being funded 95 percent by the federal government and 5 percent by state government. The state funds are being provided by Governor Pritzker's Rebuild Illinois capital program, which passed the state legislature in 2019.
The six-year bill invests $33.2 billion into transportation. “The program aims to modernize our transportation system and create economic opportunity while improving safety, mobility, and quality of life throughout the state,” according to a press release announcing the program. It adds that the program is “comprehensive and multimodal, with investments in roads and bridges, aviation, transit, freight and passenger rail, waterways, as well as bicycle and pedestrian accommodations.”
The program is sorely needed as the state last had a comprehensive, multi-year capital plan in 2009. According to IDOT’s website, “Illinois’ infrastructure has a C-rating, and deferred maintenance backlogs for our road and transit systems alone have reached $30 billion.” Over $25 billion from the plan is dedicated to roads and bridges.
William Charles Construction, which is headquartered a few hours north of the project in Rockford, Illinois, is the general contractor.
When the Interstate 57/74 Interchange Reconstruction Project is completed, the new configuration will increase mobility through the interchange by allowing vehicles to maintain higher speeds, along with increasing safety. There will be fewer points where vehicles cross paths. The third lane will reduce traffic queueing in the future. Finally, the project will help Illinois retain its position as one of the nation’s top transportation hubs.
- Owner: Illinois Department of Transportation; Project Engineer, Jason Stults, PE; Squad Leader, Ryan Carroll
- General Contractor: William Charles Construction, Rockford, Illinois
- Designers: Crawford Murphy & Tilly/Bacon, Springfield, Illinois; Farmer Workman Engineering & Testing, Maryville, Tennessee
- Other Key Contractors: Anderson Environmental Co., Chicago, Illinois; Antigo Construction Inc., Antigo, Wisconsin; Badger Daylighting Corp., Pittsboro, Indiana; Central Landscaping LP, Princeville, Illinois; Cobra Concrete Cutting Services Co., Arlington Heights, Illinois
Photos courtesy of Illinois Department of Transportation
