MANKATO — As the historic Kern Bridge prepares to rise again, so does the cost of repurposing the 152-year-old structure as a Mankato pedestrian bridge.
Construction bids for the project, expected to be underway this fall in Sibley and Land of Memories parks, ranged from $1.1 million to nearly $2 million above expectations when they were opened Friday.
Resurrecting the disassembled one-of-a-kind wrought-iron bridge and placing it on newly constructed piers and abutments is now likely to cost $10.1 million when fees paid to an engineering firm are factored in. When an associated connecting trail in Land of Memories Park is included, the price tag rises to more than $10.5 million.
The project now appears destined to cost more than quadruple what was estimated by the city’s Public Works Department five years ago when the City Council agreed to begin pursuing the bridge after it had been saved from demolition by the Minnesota Department of Transportation.
The MnDOT estimate at the time was even lower, listed as “at least $1,500,000,” when the agency solicited proposals for the bridge’s next life. The bridge was left without a purpose when its township road southwest of Mankato closed in 1991, and the span was in imminent danger of falling into the Le Sueur River before it was removed, dismantled and put in storage in the late-winter and spring of 2020.
While the limestone abutments constructed in 1873 were crumbling, the bridge itself was in relatively good condition. That — along with its historic value as one of Minnesota’s oldest bridges of any type and possibly the longest remaining bowstring arch bridge in the United States — motivated the preservation effort and made the bridge eligible for the federal preservation funds that were to provide the bulk of the financing.
Mankato officials knew from the beginning that their suggested reuse as a bike/pedestrian connection over the Blue Earth River would bring additional costs because the 189-foot Kern Bridge was not long enough to span the entire gap between the two parks. That brought the added costs of constructing an elevated section of trail in Land of Memories supported by piers, along with a section of new bridge. Those added expenses resulted in the staff estimate in August of 2020 of a $2.53 million total cost.
Since then, much of the design work and the duty of overseeing the upcoming construction was assigned to the St. Paul engineering firm of Short, Elliott, Hendrickson. In July, the City Council approved without discussion the latest contract with SEH for the next phases of the project, which will bring total payments for the firm’s consulting work to $1.7 million.
At its Sept. 8 meeting, the council without discussion approved a $439,000 contract with Nielsen Blacktopping & Concrete for the construction of a trail in Land of Memories connecting the Minneopa Trail on the park’s southwest side to the elevated trail that will be built as part of the Kern Bridge project.
The Nielson bid, the lowest of five submitted, came in 20% above the engineer’s estimate, but city staff recommended council approval nonetheless.
“Further review concludes the low bid received for these three items was similar to the other bids received, so we believe the low bid is justified, and the cost was underestimated,” a memo to the council stated.
With engineering, administration and other expenses included, the cost of the trail project rises to $577,000.
By far the largest contract for the project is the one that was out for bid through 10 a.m. Friday.
When The Free Press asked for the bidding results and for the latest engineer’s estimate for the contract, city officials initially said the requested information would not be provided because it needed to be “certified before going public.”
Minnesota law, however, requires bids for government construction projects to be provided upon request as soon as they’ve been opened, and the numbers released Friday brought more bad news.
Three firms submitted bids, all of them well above the estimated cost. Redstone Construction Co. of Mora is the apparent low bidder at $8.382 million, followed by Lunda Construction of Rosemount at $8.821 million and Kraemer North America LLC of Burnsville at $9.177 million.
If Redstone Construction’s bid is deemed to be the valid low bid after a review is completed, it will be more than 15% above the engineer’s estimate.
Mankato Interim Public Works Director Karl Keel didn’t respond to Free Press questions about next steps in the construction of the bridge and trail. As of Saturday afternoon, the issue was not on the agenda of Monday’s council meeting, and the next regular meeting on the council’s calendar is not until Oct. 14.
Rebidding the bridge project could bring substantial delays if the goal is to construct the abutments and piers and complete major work during late fall and winter, avoiding the rising river levels that typically come in the spring. The project is already running behind the schedule included in the SEH contract approved in July.
The firm suggested then that the hundreds of pieces that make up the Kern Bridge would be cleaned and painted in August and September; construction of footings, pilings, retaining walls and bridge abutments would occur in September and October; and the bridge piers within the river would be completed by the end of December.
Under that schedule, the bridge beams would have been set in January with the historic truss reassembled and set in place by cranes in April. After construction of a timber bridge deck in late April and May, the work was to be completed by June 1.
When it comes to paying the project’s bill, the anticipated share being covered by federal and state governments is plunging just as the bridge is about to go up. Expectations five years ago were that federal funds would cover 80% of the cost and that federal and state grants could be obtained to fill much of the remaining 20%.
The outside money is coming in as expected. A July 14 memo to the council stated that “federal and state funds of almost $6 million dollars” had been secured.
But the ever-spiraling price tag means those sources are providing a declining percentage of the funding, leaving the local share to potentially cover a third or more of the total bill.
“The remaining cost is anticipated to be funded with a combination of local sales tax and municipal state aid,” the July memo stated. “A full funding proposal will be presented once the project is bid and construction costs are better defined.”