New $1.8B Blatnik Bridge design unveiled; Duluth to Superior span opening set for October 2031
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Minnesota and Wisconsin transportation officials unveiled the design and construction schedule of the new bridge that will replace the Blatnik Bridge between Duluth and Superior, Wis. for area residents Wednesday evening.
The span will look similar to the original, which was built in 1961, but it’ll have improved design and safety features. The new bridge incorporates a “tied arch” design on raised piers to support the roadway 120 feet above the St. Louis River where it forms the headwaters of Lake Superior.
"This is going to be the most robust, the safest bridge we've ever done,” said Tom DeHaven, bridge design manager for the project and a National Bridge Practice Consultant with HNTB, one of the contractors working with the federal government to design and build the bridge.
“We're making everything a little bit better, a little bit stronger, just to make sure we get at least 100 years [of] service life out of this."
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In addition to four lanes of traffic, the new design also includes a 12-foot pedestrian and bike path along one side of the bridge, with alcoves to provide scenic overlooks.
Planning and preliminary construction work on the $1.8 billion project has been underway already for six years, and it will take another six years to finish it.
Demolition of the old bridge will begin in March 2027. The main span will be removed in 2027 and 2028, with the new span installed by winter of 2031. Landscaping, cleanup and other work is expected to continue until June 2032.
But the new bridge will be open to traffic no later than Oct. 31, 2031, on Halloween, said Pat Houston, major projects engineer for the Minnesota Department of Transportation.
“We do have a requirement for a closure that is no longer than 56 months,” Houston said.
Traffic will be diverted across the Bong Bridge, which crosses the St. Louis River about five miles southwest of the Blatnik Bridge. The detour will likely result in longer travel times for local residents commuting between Duluth and Superior, and for visitors to the area too.
Officials considered building the new bridge along a slightly different alignment, which would have allowed the current bridge to stay open longer during construction.
Houston said after studying dozens of options, officials concluded that tearing down the old bridge and building the new one along the same alignment speeds up the construction timeline by about a year, saves up to $100 million on the cost, and is safer. “Building that huge bridge right next to live traffic is a risk,” said Houston.
Called the High Bridge when it was first built, the bridge was renamed in 1971 after Congressman John Blatnik, who championed the project. The new bridge could be renamed, but would require an act of Congress. Houston said he hasn’t heard any discussion of a new name.
The bridge carries about 33,000 cars and trucks every day over its mile and a half long span. Ships up to 1,000 feet long also travel beneath it, to load cargoes of iron ore pellets, grain and other commodities to transport around the Great Lakes.
The new design features a wider span and more advanced safety features to protect the piers that support the bridge. Two years ago the Francis Scott Key Bridge in the Baltimore area collapsed when a container ship that had lost power struck one of the bridge piers.
Officials say the 65-year old Blatnik Bridge needs to be replaced by 2030 because of corrosion and other safety and traffic issues.
The federal government is providing about $1 billion to help build the bridge. Former President Joe Biden traveled twice to Superior to advocate for the funding, which was included in the massive infrastructure bill that he signed in Dec. 2021. Minnesota and Wisconsin are each contributing about $400 million to the project.
