Title: Lightweight Concrete Makes a Dam Float

Author(s): C. L. Tasillo, B. D. Neeley, and A. A. Bombich

Publication: Symposium Paper

Volume: 218

Issue:

Appears on pages(s): 101-130

Keywords: Braddock Dam; concrete density; float-in construction; freeze-thaw durability; lightweight aggregate; lightweight concrete; quality control

DOI: 10.14359/13057

Date: 2/1/2004

Abstract:
In initiating the final phase of modernizing the locks and dams on the Monongahela River, the U.S. Army Corps of Engineers, Pittsburgh District, used float-in and in-the-wet technology to build the new Braddock dam. This is the first use of such technology for an inland navigation project in the United States, and was employed to eliminate the cost and construction time associated with a conventional cofferdam for mass concrete construction. The new Braddock dam design was fabricated as two large, hollow-core segments. Unlike such applications used for offshore structures, the inland application was limited by navigational draft, and lock and bridge clearances. This restricted the overall dimensions and mass of the segments. The use of lightweight concrete in a significant portion of the two large dam segments was central to the success of the design. Good planning, an understanding of the concrete materials, and quality control were critical to project success.