Final designs underway for Sibley-Land of Memories connection

Nov. 7—For people wondering how an 1873 bridge can be reconfigured into a 2025 pedestrian/bike connection between two of Mankato's largest parks, the answer is in.

The final designs for the long-awaited project are being completed, with construction to begin next summer. As part of the design process, renderings now show the planned appearance of the historic Kern Bridge in its upcoming location spanning the Blue Earth River.

The vivid concept drawings show the unique wrought-iron bowstring arch bridge sitting on two large abutments extending from the water — one near the bank on the Sibley Park side and the other adjacent to the Land of Memories bank.

The 190-foot bridge — the last of its kind in Minnesota and the longest of its type remaining in America — spent its first 148 years over the Le Sueur River southwest of Mankato. It's not quite as long as the Blue Earth River is wide, plus the Land of Memories side includes low-lying land near the riverbank that's prone to flooding. So the renderings show a lengthy raised trail supported by a half-dozen other piers that will be built to connect the broader regional bike trail system to the bridge.

Engineering firm Short, Elliott, Hendrickson Inc. has been hired by the Mankato City Council to handle final designs, which are expected to be completed over the next eight months. Bids for construction of the abutments and raised trail — and reassembly of the hundreds of pieces of the dismantled Kern Bridge — would be sought sometime around July, said Assistant City Engineer Michael McCarty.

"This would set the project up for construction starting in late summer," said McCarty, who expects the initial work to involve grading on both sides of the river.

While the winning contractor will determine the overall schedule, the reappearance of the Kern Bridge after more than four years of being packed away in shipping containers could begin in about a year.

"It is anticipated that work in the river would happen in late fall or early winter when water level is most predictable," McCarty said of the final months of 2024. "Assembly of the bridge would take place about the same time and it would be installed on the new abutments once they are complete."

It's possible that people interested in the one-of-a-kind project — maybe senior citizens with fond memories of playing with Erector Sets — might possibly be able to get a glimpse of the iron pieces being precisely reattached as they were originally pinned together by builders seven years after the Civil War.

McCarty said the process could be the reverse of what happened in February 2020 near the Le Sueur River, this time with the pieces coming back together in Mankato before the structure is raised by cranes and swung in its entirety onto the abutments.

"If it mirrors the removal, it would be assembled in Land of Memories and then lifted to its final location," he said, cautioning that the location could be influenced by the plans of the winning contractor.

So the Kern Bridge could be put in place during the winter of 2024-25 when the water levels are still low along the Blue Earth River. It wouldn't be until several months later that the bridge would open to pedestrians and bikers.

"The approach spans would be installed following the installation of the bowstring truss bridge since that work can be done on land," McCarty said. "The project would be completed in the second half of 2025."

When it's done, people will be able to walk or ride between the two parks in seconds. Currently, getting from Sibley Park to Land of Memories — literally a stone's throw apart for anyone with a decent arm — requires a two-mile trip on a path long Highway 169/60.

The bridge, which was on the verge of being demolished and sold for scrap before a rescue effort led by the Minnesota Department of Transportation, will be a key piece of the existing regional trail system that connects city, state and Blue Earth County trails and of a planned trail that is to eventually run the length of the Minnesota River.

It's not a cheap endeavor. The construction portion of the project is predicted to total $4.5 million. The contract with SEH to complete the final designs includes costs for labor and services of up to $764,000. While the federal government is providing the bulk of the financing, the complexity of the project and the historic preservation goals involved bring a lengthy set of permits and reviews by state and federal agencies.

SEH was also awarded the $254,000 contract for preliminary design work. Neither contract involved competitive bids — something that is often a legal necessity for large government contracts but a requirement that can be bypassed for work requiring technical, scientific or professional training.