First shell set at Olmsted Dam

Published Oct. 18, 2010

Pam Helton, Olmsted, Ill., looks out onto the Ohio River from the Olmsted Locks and Dam visitor overlook onto America’s largest inland waterways construction project. Her husband, Wayne, is a construction representative with the Louisville District.

“My husband said I should come out to see the first shells going into the river. It’s really something to see,” she says as she reminisces about three generations of her family who lived and worked at Locks and Dams 52 and 53 which the Olmsted project will replace.

History in the making

The Army Corps of Engineers Louisville District reached a historical and critical milestone for America Sept. 22 when the first stilling basin shell for the Olmsted Dam was set into the Ohio River. The hub of the inland waterways includes the confl uences of the Mississippi, Ohio, Cumberland and Tennessee rivers. In this stretch the Olmsted navigation project has been under construction since 1993, and here, more commodities pass than anywhere in the country. Locks and Dams 52 and 53 have structures dating from the 1920s.

In-the-wet method

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 fabricated on shore and then carried into the river and set in place and put together – like giant LEGOs. There, they are fi lled with tremie concrete. In-the-wet was chosen over the traditional cofferdam because of the fl uctuations on the lower Ohio River, a concern for the environment and advances in technology.

Biggest equipment in the world

Assembly is no child’s game. Massive steel 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 in North America and the catamaran barge is the largest in the world.

The crane has a capacity to lift 5,304 tons. It moves the shells to the top of the marine skid way from their positions in the precast yard and then places them on the cradle. The cradle moves the shells down to the shoreline. From there, the shells go onto the catamaran barge. The crane remains at the top of the skid way on level ground. The crane is wheel-mounted and moves on rails.

“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 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 completed in 2016. The project will cost more than $2 billion and it will more than pay for itself within four years, according to Schipp.

“This project is so critical to the region,” Schipp said. “On the average about 90 million tons of commodities a year traverse this stretch valued at $20 billion.”

Coal is the number one commodity that moves on the Ohio River navigation system.The contractor for the project is a joint venture of Washington Group (URS) and Alberici Constructors.