Lock and Dam 9 gets replacement anchorages
The outside of the miter gates leading into the lock chamber. There are flat, circular formations of ice on the water caused by bubbling. Bubbler systems are used to pump temperature-controlled water to keep the ice from forming on the gates.
(Left) A large crane fixed to a floating barge used to transfer supplies from one area to the next. Using a crane to efficiently move supplies and tools from one side of the lock to the next, rather that moving it by foot or cart all the way around the lock. The crane is also used to break up ice formation for traveling purposes during the off season. Each barge has a different rated capacity for what it can lift, and the barge itself can dictate what weight the machine can bear because the barge can list.
A look at part of the anchorage and concrete work being done at Lock and Dam 9 near Lynxville. (Photos by Steve Van Kooten)
By Steve Van Kooten
Between this past December and February, the U.S. Army Corps of Engineers St. Paul District conducted work on Lock and Dam 9 on the Mississippi River near Lynxville that included improvements to the concrete and the installation of new anchorages.
The anchorages act as the hinges for the gates, but they’re not exactly like your average car door. The miter gates are sets of 100-ton gates that allow vessels access to the lock chamber.
“If you think of a regular passenger door, it only hinges into the wall. Our hinges actually go one hinge along with the wall when the gate is in one position and one hinge into the wall for when the gate is in the miter position,” Jim Cook, the project manager, said.
He added that the double-hinge system helps the connection bear the heavy weight of the miter gates regardless of the position they are in.
According to Mike Holzer, engineer for the project, the upgrade to the anchorages — which were installed in the 1940s — is both a necessity and long overdue.
“The original design life was 50 years, and they’re 90 years old now,” he said. “With the new miter gates, they’re roughly 100,000 lbs. heavier than the original ones, so that’s the justification... They’re sort of like the door hinges, so they’re kind of the weak link in the whole connection. So, we wanted something that would ensure that the gates were meeting the 100-year design life. It’s one more component in the mission to replace the miter gates.”
The current miter gates are 50 years old and are due for replacement in the summer of 2026. According to Cook, the new gates are being made by a company in Georgia.
“We’ve got new [gates] for this lock coming in two years, and they are bigger and heavier,” Cook said. “They fit into the same spot, so height and width, they are the same. Some of the work they’re doing is preparation for upgrading the gates. The upgraded gates will function the same way, but they’ll be able to handle a barge impact or a flood.”
If an anchorage fails and the gates cease to be functional, Holzer said it would have a significantly detrimental effect on the country’s economy — we’re talking millions of dollars in lost revenue and delays. The locks and dams are infrastructural necessities for the country’s economy.
“It would basically shut down the workers and the navigation industry for however long it takes to make that repair or replacement,” he said.
Replacing a broken anchorage would not be a quick fix either.”
Depending on if we have that component available to us. This steel we use to fabricate these anchorages took close to a year to procure... it’s a very specialized structural steel, and we had to have a machine that we could fit in here. That machining process took a month or so. To replace it, we would act very quickly, but it could be weeks or months,” Holzer said.
He added that emergency repairs have shut down the river for weeks in the past.
The Corps of Engineers reported that the project cost approximately $1.5 million.
Corps projects largely receive funding through annual appropriations, which are federally authorized funds accrued through taxes and fees paid by citizens.
“It’s appropriated through maintenance funds. The headquarters tells Congress what our needs are to maintain the infrastructure in accordance with the mission we’ve been given nationally, and then headquarters distributes that based on priority of needs,” Cook said. “It’s a very deliberate process. Congress is in consultation with local leaders. There are representatives who work on committees and say, ‘These are the needs of my district,’ and then they put in a pot and stir it together, and the priorities that rise to the top get funded.”
On Feb. 19, Cook claimed the anchorage installation was on time, on budget and had zero reportable injuries. He credited the combined efforts of the engineers, designers, divers and other workers for the project’s success.
“These are technically competent, dedicated professionals who want to do the work because it’s interesting and it’s helpful at scale—helpful locally, helpful for industry, and that bubbles all the way back up to the source of the funding.”
