A closer look at the restoration work underway on the Stone Arch Bridge

A closer look at the restoration work underway on the Stone Arch Bridge

A closer look at the restoration work underway on the Stone Arch Bridge

It’s a $38.5 million makeover.

“The Stone Arch Bridge was built in 1883, and it needs to be tuckpointed again,” says Ward 3 Council Member Michael Rainville.

Tuckpointing is a process where aging and damaged mortar is removed and replaced with fresh material.

Right now, a Minnesota Department of Transportation contractor team is examining the bridge stone by stone before using circular saws to chip out mortar in between that’s been eroded by our freeze-thaw Minnesota weather.

The transportation agency says water is the bridge’s biggest enemy.

“So, think about all those water molecules that are inside of the mortar when it becomes really cold,” explains Katie Haun Schuring, MnDOT’s architectural historian. “They freeze and then they expand. It breaks up the mortar a little bit over time, and eventually, that mortar will start falling apart.”

RELATED: With construction on the Stone Arch Bridge starting Monday, people take their last walk across the complete span this weekend

Those newly repacked mortar spaces are designed to last up to 150 years — and to slow deterioration. 

“It’s restoring the bridge, so it’s keeping it structurally sound for people to use it for many years to come,” notes Jesse Johnson, a MnDOT spokesperson. “We want to make sure we’re doing it safely and being good stewards of this historic resource.”

But this is no ordinary facelift.

“The stones that have the orange spray paint on them, these are the stones that are going to be replaced,” Haun Schuring explains.

She notes some of the stones — cut from limestone in pieces 6 feet long and 2 feet deep — will be either replaced or shaved down.

“So when we take those stones off, we’re not going to actually take the entire stone deck away,” Haun Schuring says. “We’re only going to take however many inches or up to a certain number of inches until we hit that solid stone.”

When needed, work crews will attach a stone veneer, held in place by rods and posts.

The exteriors will be tooled to give the exterior surfaces a weathered look.

Haun Schuring says replacement stones will come from quarries in Iowa and Mankato. The latter is the same quarry used when the bridge was originally built 141 years ago.

“They are very, very similar in color, which is great,” she says. “Because it’s the same kind of stone and it’s from the same quarry. We know there were a hundred thousand tons of stone brought in from three different quarries.” 
Haun Schuring says some of the stones go in quite far, and those sections isolated from the elements are in pretty good condition.

We wondered if the entire bridge is packed solid with stone.

Turns out, it’s not.

“We can’t take the whole bridge apart,” Haun Schuring explains. “The inside of this structure is hollow, so there are places where it’s not all stone all the time, you’ve got a hollow sort of core inside of that.”

She says in the early 1900s, work crews added reinforced concrete on the inside of the arches to handle the weight of heavier rail cars.

Fast-forward to this year, when work began on the St. Anthony Main side in mid-April and will continue until the spring of 2025.

After that, crews will repair the downtown side until the fall, with the project scheduled to be completed by the spring of 2026.

“This is a testament to how this neighborhood and this area has changed,” Johnson says. “People riding on passenger rail, and then eventually turning this into a pedestrian-bike bridge.”

It’s a huge job.

Crews are using scaffoldings to repair the bridge’s sides and lifts on a barge to work on the arches underneath.

Inspectors will check the steel tie rods that keep the span’s walls from splaying out, and they’ll expand the interior drainage system that runs from the bridge deck to giant pipes on the sides.

The project includes the first repairs since the Stone Arch became a pedestrian bridge in the mid-1990s.

Both ends of the span are in the 3rd Ward — one reason why Rainville keeps close tabs on the progress. 

“So we have to celebrate that we’re going to have a Stone Arch peninsula, and it’s going to take time to do it,” he says. “It’ll always be a part of the social fabric, the opportunity to recreate and enjoy the riverfront, to draw us closer to the water.”

MnDOT says when the two-year project is finished, the bridge will be usable for generations to come.

“This is one of the most monumental bridges in Minnesota,” Haun Schuling declares. “Now, to actually see it coming to fruition and being built and rehabilitated is going to be really special.”