Page - 99 - in Book of Full Papers - Symposium Hydro Engineering

SUMMARY In summary, the use of RCC for the foundation replacement provided a robust solution for the Oroville Emergency Recovery – Spillway Task Force. RCC was used to backfill the eroded bedrock chasm within the original damaged FCO Spillway chute area with a high- strength cementitious material, which provided support for the future reinforced-concrete spillway slabs and walls. The RCC was placed within the limited time window to construct an operational FCO Spillway chute for the 2017-2018 Winter Flood Season. Several aspects of this application of RCC were innovative, including the expedited time frame for design and construction; RCC placement on a 4:1 slope with sloping walls; use of an enriched RCC overlay for a robust surface on a high-capacity/high velocity chute spillway; and RCC placement in a challenging rock foundation, using a combination of vibratable RCC with and without mix enrichment with grout. The RCC solution utilized the reuse of scoured rock debris, and had the least environmental impacts of the alternatives considered. It provided a robust bidding climate as a majority of the construction means and methods were well known in the dam construction industry. It provided a competitive bidding process, which resulted in a low unit bid price. RCC was placed continuously and rapidly to complete the FCO Spillway chute recovery within the limited time frame. The contractor, Kiewit Corporation, was instrumental in the success of RCC with its commitment to a quality constructed product. The contractor’s willingness to experiment and come up with new ways to place RCC on a challenging foundation was instrumental in achieving the desired design intent. The speed of construction, economy of materials (including the reuse of scoured/eroded rock), innovative contractor placement methods, and material adaptability to variable foundation conditions made the use of RCC as foundation replacement in the FCO Spillway chute an ideal solution for Oroville Emergency Recovery. REFERENCES [1] California State Water Project Bulletin 200, State of California Department of Water Resources, 1974 [2] CROYLE, W., GUTIERREZ, D., ANDERSEN, M., LEDESMA, J., TAPIA, S., and BLACKETT, F. Oroville Dam Spillway Incident – Situation Development, Incident Response and Public Safety “Oroville Dam Spillway Incident – Fast Track [3] CRADDOCK T., HARDER L., VERIGIN S., KUTTEL J., BROWN D., MIHYAR M., BOYER D. Oroville Dam Spillway Incident – Fast Track Recovery Design to Address Critical Dam Safety. [4] NICHOLS, H., GRAY, M., HALL, C., KUTTEL, J., and CRADDOCK, T. Oroville Dam Spillway Incident – Geological and Geotechnical Investigations for Recovery Design Features [5] PANDEY, G., FORD, D., CRADDOCK, T., WHITE, M., FORTNER, M., LEAHIGH, J., ANDERSON, M. Oroville Dam Emergency Response and Spillway Restoration – Hydrologic and Hydraulic Engineering Activities to Inform Operation and Design 99