Olmsted Dam is one of the largest civil works projects undertaken by the United States Army Corps of Engineers (USACE) and is located on the busiest stretch of U.S. commercial inland waterways. More tonnage passes this point than any other in America’s inland navigation system. Olmsted Dam will be the last dam on a system that provides a year-round channel for navigation that begins at Pittsburgh, Pennsylvania and ends at Cairo, Illinois. Olmsted Dam will replace two of the original locks and dams that were completed in 1929. An AECOM-led joint venture is building the dam in an innovative “in-the-wet” method to minimize impacts to river traffic and the environment.

Click here to view a video about the Olmsted Dam project.

Olmsted Dam construction consists of producing precast concrete shells, the largest of which will weigh more than 4,996 tons. The shells, which are 100 feet wide, 100 feet long, and 30 feet tall, are lifted by a super gantry and moved to a cradle at the river’s edge. Once on the cradle, a catamaran barge in the river lifts the shell off the cradle and transports it into the river where it is lowered onto its respective foundation. They are set under water on a prepared bed, and once the shells are in place, tremie concrete is pumped into the annulus area under the precast shells to form a continuous bond between the pipe piles, rebar, and the surface shell.

AECOM engineers and the on-site construction team created innovative solutions and utilized resources throughout the company to finalize our means and methods and creative ways to manufacture the specialized equipment. Major innovations include:

  • One of the largest civil projects undertaken by the U.S. Army Corps of Engineers
  • Only Illinois construction project to receive prestigious Occupational Safety and Health Administration (OSHA) Voluntary Protection Programs Star Status
  • One-of-a-kind equipment and methods created for heavy lifting, pile driving, setting large concrete shells, and protection of the river bed
  • Largest gantry crane of its kind able to lift 5,300 tons
  • Aqua digger that is one of only two of its kind in the world
  • Amazing accuracy with state-of-the-art sonar, real-time kinetic global positioning systems (GPS), and survey methods