Two springs ago, the original 1939 swayback bridge in Ramsey Park was once again hit by floodwaters.
The bridge was built for that. The unique downward-curve of the bridge was designed to withstand floods by letting floodwaters flow over it.
However, decades of minor damage took a bigger total toll than was known. It turned out the original concrete deck was much thinner than anyone knew.
Last week the county started a $670,000 project to totally refurbish the swayback bridge.
Step one is completely tearing out and replacing the original 1939 10-inch thick concrete deck.
Last week a New Jersey company set up a “de-watering” system around the eastern half of the bridge so a construction crew can work underneath it.
According to Jeff Bommersbach, Redwood County Highway Department Senior Engineering Technician, the company originally planned to dam the river with metal plates.
However, the rocky river bottom required everyone to go to Plan B — plastic sheeting and hoses to divert the water across just part of the river.
“It’s not foolproof,” Bommersbach said. “The repairs will have to be in two phases.”
First the river will be blocked on the eastern side of the bridge. Once repairs are finished there, the western side of the river will be dammed so crews can get underneath the western side of the bridge.
In addition, the granite and concrete piers will need extensive rehab work.
Part of the funding for the repairs is coming from the Minnesota Historical Society. One of their requirements is that the bridge be put as close to its 1939 condition as possible.
That involves having to replace missing granite blocks with stone from the same quarry, if at all possible.
“We had a source that was able to find some of the same granite, taken from when they tore down the Memorial Field stadium (to create the aquatic center),” said Bommersbach.
Once any missing granite blocks are replaced, the concrete holding them together will be repaired and, in many places, completely replaced.
“It’s going to be a slow process. Everyone’s being real careful not to get any old concrete in the river,” Bommersbach said, adding they’re still on track to complete the project by the end of September.
“It’s still a good old bridge,” Bommersbach said. “We’d just like to ask everyone to stay off the bridge. Especially with all the equipment around, it’s not safe for people to walk across.”