American Falls Dam Spillway Repair

American Falls Spillway Repair

Winspear Construction is the General Contractor for the concrete rehabilitation work on the downstream side of American Falls Dam in Idaho. Concrete improvements to the spillway, the stilling basin immediately below it, and other parts of the dam aim to extend the life  of the structure and modernize it. The project is to take place over 2 years with a construction window only a few months a year. Currently Winspear Construction is in the first phase of the project, which includes the demo and construction of a new concrete face on the spillway.

Project scope comprised of removal of approximately 6” of concrete on the Spillway Face to expose sound concrete. The concrete will be replaced with a 6” lift of replacement concrete. The Stilling Basin, which will start in the second year of construction, will include removal of 4” thick epoxy bonded overlay plus an additional 2” of original concrete below the overlay. The removed concrete will be replaced with 6” overlay and single mat of reinforcing doweled into the existing concrete. In addition to the spillway and stilling basin, includes demolition and construction of two new gallery adits. A temporary road was constructed in order to provide access for equipment and material to the work site.