Minnesota Department of Transportation

511 Travel Info

I-535 Blatnik Bridge

Duluth, Minn. and Superior, Wis.

About this project

A rendering of the Blatnik Bridge location.

Click image for full-size PDF

MnDOT is working toward a future project to address concerns about the John A. Blatnik Bridge, one of two bridges that connects Duluth, Minn., to Superior, Wis. Carrying I-535 over the St. Louis Bay, the Blatnik is an important freight and commercial connection between the Twin Ports.

Jointly owned and managed by MnDOT and WisDOT, it is Minnesota’s second longest bridge and serves an average of 33,900 cars traveling between the two cities each day. MnDOT will lead the project, which will address aging infrastructure, improve safety and better accommodate oversize/overweight loads.

Project purpose

  • Significant deterioration in truss elements
  • Safety inspection is required every year, which requires lane closures for one to three weeks
  • Additional maintenance causes lane closures up to three times annually
  • Significant steel and cable repairs were required in 2016 after inspection revealed increased deterioration
  • Reactionary structural repair needed every four years
  • In June 2019, main truss span and approach spans were load posted for 40 tons and therefore can no longer accommodate overweight loads
  • Increased road user delays for scheduled bridge maintenance activities and inspections