January 18, 2018 05:50 AM
The historic Stone Arch Bridge in Minneapolis is deteriorating so quickly it's at risk of being closed down if it's not repaired soon, according to the Minnesota Department of Transportation.
The work will cost taxpayers about $13 million, according to Gov. Mark Dayton's bonding bill proposal released Tuesday.
That's far more money than even engineers realized as recently as one a year ago.
"It could get to a point where we would have to close it," MnDOT state bridge planning engineer Amber Blanchard said.
Blanchard said two bridge inspections, conducted last summer and fall, exposed unexpected problems on the more-than-100-year-old bridge.
She said the two biggest issues are the bridge's stone blocks and mortar - adding that 20 percent of the blocks need to be replaced and 100 percent of the mortar needs to be repointed.
"Repointing will basically chip away at the mortar," she said. "Maybe five, six, seven inches. It kind of depends on the deterioration as you go into the mortar itself between the concrete blocks.
"It'll chip away at that until you hit sound mortar, and then you'll replace the mortar."
Complicating matters, though, is how the state will pay for the work.
"Because the Stone Arch Bridge is not on a trunk highway, we can't use trunk highway dollars to actually fund this bridge," Blanchard explained.
"So we have to either request special general obligation bonds or other types of funding to be able to meet the needs of the bridge."
Which means the funding likely has to be appropriated by the state legislature, she added.
So what happens if MnDOT doesn't get the money? The short answer is Blanchard isn't sure.
"It's really hard to say because the deterioration varies over time," she said. "Once it starts, it usually accelerates. But it's kind of hard to say at this point."
Even if the $13 million is appropriated during the coming legislative session, there will still be a lot of work ahead. Because repairing a bridge that's been around since the 1800s is such a major undertaking, Blanchard believes construction would start in the summer of 2020 at the earliest.
Updated: January 18, 2018 05:50 AM
Created: January 17, 2018 07:10 PM
Copyright 2018 - KSTP-TV, LLC A Hubbard Broadcasting Company