- Client:U.S. Army Corps of Engineers
- Location:Olmsted, Illinois, USA
- Contract Amount:$1,600,000,000
An Alberici joint venture is constructing a dam across the Ohio River using an innovative technique in which the dam is being built without a cofferdam.
The Olmsted Dam will include five 110-foot tainter gates and a navigable pass section with 1,400 feet of boat-operated wicket gates. A weir will tie the dam into the Kentucky bank.
In traditional dam construction, a temporary cofferdam is built to keep water away from the site. In an innovative approach, the Washington Group-Alberici joint venture (WGA) is constructing the Olmsted Dam without a cofferdam by driving pilings into the river bottom to form a foundation. WGA then places precast concrete sections on the foundation to construct the dam “in the wet.” This “in the wet” method has less impact on the riverbed.
WGA is utilizing an onsite concrete batch plant to make 47 concrete shells, the largest of which will weigh in excess of 2,700 tons. The shells are approximately 125 feet wide, 125 feet long, and range in height from 30 to 75 feet. They are lifted by a 5,100-ton gantry crane and moved to a skidway where they are then transported to the river's edge. From there, a catamaran barge transports the shells out into the river where they are lowered into place.
Once the shells are set, concrete is pumped into the area under the shells to form a continuous bond between the foundation and the shells.
WGA has self-performed 96.5 percent of the work, including river bed excavation, pile driving, and casting and placement of the concrete shells.
To see a video on the Construction Innovation Award given to the WGA team, please click here.