Even with all of the road and bridge construction still to come in Duluth’s Lincoln Park neighborhood, finishing touches are already emerging.
Late last month, the new 27th Avenue West bridge opened over Interstate 35.
Lately, crews have poured concrete to seal the new outlet end of the combined Coffee and Miller creeks emptying into the St. Louis Bay.
“There’s a lot of eye candy as part of the project progress right now,” Pete Marthaler said of the $343 million Twin Ports Interchange reconstruction project.
Marthaler is the Minnesota Department of Transportation’s major projects manager in charge of the work, and he was speaking last week during a virtual public update about the project.
One location where ongoing change is evident: the closed southbound lanes of I-35, where soil is being hauled away as contractors make good on a promise to use fewer sections of elevated roadway. Work is dubbed the “southbound mainline profile correction.”
“We are lowering the profile to make better sight distances when we’re done,” Marthaler said, echoing goals of the project to make the confluence of I-35, I-535 to Superior and Highway 53 toward the mall safer for all travelers, and usable by oversize loads, such as trucks carrying wind turbine blades.
Any contaminated soils removed from the work area are trucked to a stockpile site established in Hermantown. The construction worksite was well-understood by MnDOT engineers to be laced with contaminants and materials of the past.
“A lot of the soil isn’t so high (in contaminants) it requires immediate disposal,” Marthaler said. “Some of it does qualify as industrial reuse.”
Workers from the joint construction venture between Ames Construction, of Burnsville, Minnesota, and Kraemer North America, of Wisconsin, encountered some of the legacy materials while sealing the outlet of the combined creeks.
Marthaler said crews ran into timber pilings from an old railroad trestle. The pilings had to be removed by divers using underwater demolition equipment, including a pneumatic-powered chainsaw.
“We had to remove those; otherwise if they projected through that seal, we would have a perpetual geyser and we wouldn’t have been able to do our work in the dry, which is both necessary for safety and quality of the concrete,” Marhaler said, describing dry work using a temporary cofferdam to hold back the water.
The effort to merge the underground portions of Miller and Coffee creeks is the highest-profile work happening at the moment.
Work will create an open channel of Coffee Creek in the neighborhood for the first time since 1891. Coffee Creek is being relocated from underneath U.S. Highway 53 in order to make way for new flyover bridge piers.
Because soils are so soft throughout the neighborhood, steel piles will be used to support the new culvert carrying the creek.
“In the coming weeks you’ll start hearing pile-driving activity,” Marthaler said.
Creek work has included blasting through rock to create the new inlet end of the combined creeks — work that’s being done in the vicinity of the closed lanes of southbound I-35.
“We had to do some rock blasting,” Marthaler said. “Hats off to the subcontractor; they did a really good job and they did it safely.”
Once work on the inlet and outlet ends is completed in the fall, four-way traffic along I-35 through Lincoln Park will resume with Lower Michigan Street being prepared as a southbound bypass. Northbound traffic will use I-35's south lanes, and the freeway's north lanes will be closed to allow for work between the creeks’ inlet and outlet.
Marthaler said travelers can expect four lanes of I-35 traffic to resume in late October. Currently, traffic headed north and south is relegated to the north lanes on I-35.
Marthaler said he still runs into people who can’t comprehend the four-lane configuration.
“It’s hard for them to visualize,” he said. “There will be two southbound lanes (of I-35) on Lower Michigan Street with concrete barriers on both sides.”
Other project highlights to date:
“We moved the Cross City Trail,” Marthaler said. “They now have a dedicated, protected bike lane along the lower side of Superior Street through Lincoln Park between Michigan all the way to 22nd Avenue West.”
Completion of the city’s new lift station No. 15 underneath the Highway 53 flyover bridges. It was more economical to build a new one than contend with the existing one where it was, the project manager said.
Contractors are pile-driving and pouring footings as they build new bridge piers, and an earth retention system adjacent to rail tracks at the BNSF yard.
No matter what happens construction-wise with closures, Marthaler said the goal is to maintain access through Lincoln Park on two of three streets at all times between Superior, First and Michigan streets.
Workers had logged 100,000 hours without a recordable injury as of early last week.
“There’s a lot of pride in that number,” Marthaler said.
Weather is cooperating well, and work is going efficiently, Marthaler added. Contractors will be working year-round on the project until completion.
“About 27 more months we should be in the clear,” Marthaler said, targeting final completion in summer 2024.
This story was updated at 12:17 p.m. July 4 to correct the name and location of contractor Kraemer North America, based in Wisconsin. It was originally posted at 2:41 p.m. July 3.