The U.S. Army Corps of Engineers, Rock Island District, which oversees operations and maintenance of Locks and Dam 15, mobilized a maintenance crew to address structural concerns on the downstream guidewall.
According to Aaron Dunlop, Operations Project Manager for the Rock Island District’s Mississippi River Project, four monoliths making up a portion of the guidewall are being demolished as the failing concrete is creating risk to the navigation system.
The demolition work, which should not affect barge traffic, began Saturday and will continue for approximately two weeks.
“The lower 120 feet of the guidewall is structurally failing, which could result in it falling into the navigation channel,” Dunlop said. “If it were to fall into the channel, this would block navigation for nearly a month as crews would need to respond to remove the broken concrete blocking access to the lock chamber.”
Dunlop also said that his crew has been working with a team of Rock Island District engineering and operations staff. After close monitoring of the guidewall section, the team determined the best course of action was to proactively remove the concrete to prevent it from falling in an uncontrolled manner. He added that the demolition is the temporary fix. A contract for permanent repairs will likely be awarded later this summer.
The section of guidewall that is being demolished is original to the project. Locks and Dam 15 was the first lock completed on the Upper Mississippi River as part of the 9-foot navigation system. Construction at Locks and Dam 15 finished in 1934, and the intended design life of the lock was about 50 years.
According to Mike Cox, Chief of the Rock Island District’s Operations Division, locks like those at Locks and Dam 15 have outlived their design life due in most part to adaptive maintenance and periodic major rehabilitation.