MnDOT to defer portions of Twin Ports Interchange project
Duluth, Minn. – Due to a roughly $100 million funding gap, MnDOT will need to defer portions of the Twin Ports Interchange project.
Design plans for the TPI project are 60% complete or more, which means MnDOT is learning more and more about the scope of this project as it progresses.
“With large, complicated urban projects like this, it is difficult to estimate the overall project cost until engineering has advanced,” said MnDOT Assistant District Engineer Pat Huston. “Cost comes incrementally as design advances, and this is why the initial estimates were lower than they are today.”
The project was budgeted for $343 million, but with the advancement of design plans, the cost has grown to closer to $442 million as of today. That number could change again as plans progress.
That funding gap means MnDOT will need to defer work on the Garfield Avenue Interchange and the Highway 53 bridge. MnDOT plans to continue design of those two phases so as soon as funding become available, they can move forward with the projects.
“There are many complex reasons that led to project costs being higher than estimated during the planning stage,” Huston said. “The TPI project team knows more now through the engineering that has been completed to date.”
Most of the soil and water around the project area are contaminated and need special handling and treatment. Other added costs include geotechnical challenges with the poor mixture of soils, maintaining two lanes of southbound traffic on Lower Michigan Street for a portion of the project, and the extent of work on Coffee Creek and Miller Creek due to shoring and utilities.
Through engagement and engineering efforts, MnDOT identified the prioritized work to include Coffee Creek and Miller Creek culvert construction, work along the I-35 corridor and utilities associated with the entire project. As design on the project as a whole continues to move forward and be refined, project costs will continue to change. The state will continue to look at all possible funding options including new transportation funding.
“The Highway 53 bridge is in poor condition and will need replacement, so ongoing maintenance will be required because of the deferment,” said MnDOT District Engineer Duane Hill.
“However, the bridge is safe and we will do whatever is necessary to keep it safe and operational until it can be replaced.”
MnDOT will move forward with the TPI project in 2020 rather than deferring the entire project until there is funding for all phases. The construction timeline for what will be built (I-35 mainline, main interchange and 27th Avenue West bridge replacement) will be as originally planned, 2020-2023. The timeline for the Garfield and Highway 53 phases will be determined when funding becomes available.