The Army Corps of Engineers Louisville District reached a critical milestone for America’s inland navigation system Sept. 22 when the first stilling basin shell that will comprise the Olmsted Dam was set into the Ohio River.
At the hub of the inland waterways near the confluence of the Mississippi and Ohio and near the Cumberland and Tennessee rivers, the Olmsted Locks and Dam project has been under construction since 1993. More commodities pass this point than anywhere in the country. The new Olmsted Locks and Dam will replace Locks 52 and 53 which contain remnants from the 1920s.
The Corps is using an innovative method known as in-the-wet for the construction of the Olmsted Dam. Sections of the dam, the shells, are prefabricated on shore in a precast yard, carried into the river and set in place and put together – like giant LEGOS. There, they are filled with tremie concrete. In-the-wet was chosen over the traditional cofferdam because of the fluctuating river on the lower Ohio, a concern for the environment and advances in technology.
Assembly is no child’s game. Monolithic and massive equipment specially designed for the project is used to assemble, move, lift and place these shells, the largest of which weighs 4,700 tons. The super gantry crane is the largest gantry crane in North America and the catamaran barge is the largest in the world.
The super gantry crane moves shells from the top of the marine skidway to the shoreline and onto the catamaran barge which moves shells into position on the river. The crane is wheel-mounted and moves on rails. The super gantry crane has a capacity to lift 5, 304 tons.
“You could just about put a 10 story building under it,” said Rick Schipp, Louisville District deputy construction engineer.
The catamaran barge moves the shells out into the river and then lowers them as much as 20 or 30 feet deep below the water depending on river elevation.
Bill Gilmour, Louisville District Olmsted resident engineer, hopes the construction team will be able to set six shells this low water season. “We’d like to make as much progress as we can conditions allowing,” he said.
Six low water seasons are required for the dam construction. The Olmsted Locks and Dam project is currently scheduled to be complete in 2016.
The project will cost nearly $2 billion, and it will more than pay for itself within four years, according to Schipp.
“This project is so critical to the region,” said Schipp. “More than 90 million tons of commodities traverse this point valued at $20 billion.”
Coal is the number one commodity that moves on the system.
To view time lapsed YouTube videos go to: <a href="http://www.youtube.com/louisvilleusacehttp://www.youtube.com/louisvilleusace">http://www.youtube.com/louisvilleusace</a>