The construction of a new I-80 bridge over the Mississippi River will take four years to complete once started, and will require demolition of the existing 57-year-old bridge.
Dreams to repurpose the existing four-lane bridge (connecting LeClaire and Rapids City) were dashed Wednesday, as the Illinois and Iowa departments of transportation announced a preferred alternative, requiring demolition of the current bridge.
The preferred option involves the construction of two parallel structures, one eastbound and one westbound (as in the new I-74 bridge) — each two through lanes, plus an auxiliary lane to facilitate traffic exiting and entering I-80 from Illinois 84 in Illinois and US 67 in Iowa.
The first bridge will be built just downstream and adjacent to the existing bridge while traffic continues on the existing bridge, according to a Thursday email from Steve Robery, an engineer with the Illinois DOT based in Dixon.
“Once the first bridge is complete, both directions of traffic will be shifted onto the new bridge, the existing bridge will be demolished, and construction of the second bridge will begin over the footprint of the existing bridge,” he said. “Once both bridges are completed, one bridge will carry eastbound traffic and the other will carry westbound traffic. Re-using the footprint of the existing bridge allows a more compact configuration with fewer impacts to the human and natural environment.”
Of the bridge replacement alternatives that were carried forward for detailed study following an October 2022 public meeting, two alternatives required the space presently occupied by the existing structure, and two alternatives did not, Robery said. “Alternate 5, which does require that space, was chosen as it resulted in the least impacts to the human and natural environment.”
The cost estimate for the construction of the bridge and the I-80/I-88 interchange is $288 million, which will be refined as the project develops and the programmed estimate (the amount funded for the project) will be adjusted accordingly.
Robery said the current construction timetable is four years, which also will be refined as the project is further developed. Funding for construction is included in the Illinois Fiscal Year 2024 through 2029 Multi-Year Program as well as Iowa’s current Multiyear Program.
“We do not currently have a definitive time that construction will begin as additional engineering work needs to be completed along with associated land acquisition activities,” he said.
A preliminary estimate of the demolition cost for the current bridge is $2 million to $4 million, which will also be refined as the project develops.
The Bison Bridge Foundation spent over three years collecting financial and community support for repurposing the existing bridge to be used for pedestrian and wildlife crossing, and potentially a new national park.
For more information on the I-80 bridge project, click HERE.