The Minnesota and Wisconsin Departments of Transportation are planning to replace the St. Croix River bridge between Osceola and Franconia Township in the summer of 2025. The nearly 70-year-old span is in poor condition.
The agencies are asking for comments on a draft Purpose and Need Statement, with a 15-day comment period closing on Friday, June 4.
The project is only in its beginning phases, with full environmental review to come. The document is “used as a guide to evaluate alternatives and eventually select a preferred option.”
“The Highway 243 bridge gained a bit fame after the I-35W bridge collapse in 2007 due to the bridge being one of the few remaining deck truss bridges in Minnesota,” wrote bridge expert John A. Weeks III. “A deck truss bridge has a metal lattice work of cross members, with the roadway being built on top of the truss. The deck truss is considered to be an obsolete style of bridge.”
There are several reasons the deck truss design is no longer used, adding up to the fact that they are expensive to maintain. The bridge now receives routine inspection and maintenance, and is not considered deficient, but is reaching the end of its useful life.
One possibility being considered for the replacement is the addition of pedestrian accommodation. The bridge connects the village of Osceola with popular Osceola Landing, operated by the National Park Service. The span is currently two lanes with narrow shoulders unsafe for bicyclists or pedestrians.
The existing bridge is two lanes and carries about 5,700 vehicles per day. The nearest river crossings are on U.S. Highway 8 in Taylors Falls and St. Croix Falls, about seven miles upriver, or the Highway 36-Highway 64 bridge near Stillwater, more than 20 miles downriver. The Highway 8 route results in a total 18-mile detour.
The 674-foot long bridge is located wholly within the St. Croix National Scenic Riverway, and a landmark for many river users. It is also located in important habitat for rare fish, mussels, and other wildlife.
“The project team will coordinate with federal, state and local interests in the planning for the project to minimize project impacts to the St. Croix River and other natural resources in the area,” the agencies said.
The Highway 243 bridge is notable because of its location adjacent to Osceola Landing, which is used by many boaters, anglers, picnickers, paddlers, and more.
The stretch of river from Interstate Park to Osceola Landing is possibly the most popular canoe or kayak trip on the river — paddlers using the services of rental and shuttle outfitters pass under the Highway 243 bridge right before pulling off the river.
“It is important to ensure that the St. Croix River remains open to navigation and that the Osceola Landing remains accessible for recreational and commercial users during the peak recreational months in the summer, and that any river navigation closures during construction are minimized to the extent possible,” the agency report reads.
The agencies say federal law requires them to evaluate project impacts on endangered species that are present.
The National Park Service is also preparing to begin an extensive renovation of Osceola Landing this summer, to be completed by 2023. The state agencies say they will work with the park so the bridge replacement and landing renovation are coordinated.
Adding a left-turn lane for westbound traffic to turn into Osceola Landing could be part of the project.
Limited life left
Built in 1953, the Highway 243 bridge is reaching the point where repairs won’t be possible or cost-effective.
It has been closed several times in recent decades due to damage and extensive repair projects. In 1980, the entire bridge deck was replaced, and in 2010, an extensive restoration project closed the span for a summer. In 2017, it was closed abruptly due to a large hole appearing in the bridge deck.
Bridge engineers assess a span’s condition with a scoring system that results in a number between 0 (closed to traffic) to 9 (new and perfect condition). The Highway 243 bridge’s most recent score was a 4 for the deck, which is poor, the superstructure at 5, which is considered fair, and the substructure at 6, or satisfactory.
Overall, the bridge ranks fourth most in need of replacement of the may bridges in MnDOT’s Metro district.
But not only are its steel supports rusting and its deck corroding, the outdated design has many drawbacks.
“The reasons include being fracture critical (i.e., non-redundant, which means that any one piece breaking can result in the entire bridge failing), they are very hard to inspect (the structure is under the road rather than above the road), they are easily damaged by road salt (which can leak though cracks in the deck and cause the steel to rust), and truss bridges are far more costly to maintain,” writes Weeks.
The Highway 243 bridge offers beautiful views of the St. Croix River looking both upstream and downstream, but most people only glimpse it while driving across at 45 miles per hour. People on foot or bicycle are allowed on the bridge, but its narrow shoulders and high traffic volumes make it unsafe.
Dedicated areas for pedestrians and bicyclists would open up opportunities to stop and enjoy the river views. It would also provide a valuable connection for bicyclists who enjoying riding in the St. Croix Valley.
To analyze bicycle use, the agencies analyzed data from the popular Strava application, which cyclists use to track rides.
“On average, 12 cyclists using the Strava application cross the St. Croix River on the Hwy 243 Bridge daily, with an increase in the number of users during the summer months, similar to vehicular traffic,” the agencies report.
The current shoulders are 3.6 feet wide on both sides of the 12-foot driving lanes. MnDOT’s standards call for a minimum of 10 feet for pedestrians.
“These shoulders do not meet MnDOT standards for pedestrian use,” the agency reports.
A new bridge is needed, and the replacement could open an entirely new way to enjoy the river.
To review and comment on the draft purpose and need statement, visit the project webpage at mndot.gov/metro/projects/hwy243osceola.
Comments also can be made by email at firstname.lastname@example.org or by mail to MnDOT, Attn: Dmitry Tomasevich, 1500 W. County Rd B2, Roseville, MN 55113-3174.
Comments submitted on or before Friday, June 4 will be recorded and considered for the final purpose and need statement.
Hard copies for viewing are also available at the Osceola Village Hall (310 Chieftain Street, M-F 8:00 am – 4:00pm).