Author(s): Andrew M. Tuthill; Meredith L. Carr
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Keywords: No Keywords
Abstract: Large scour holes were recently discovered upstream of Melvin Pr ice Dam, the largest navigat ion structure on the Mississippi River. This dam, built in 1989, has nine 33.5-m-wide gates that maintain a minimum pool depth of about 12 m. Stone bed protection upstream of the dam was designed to withstand estimated bed shear forces for a 100-year open water flood. The scour damage was repaired at a cost of over $1 million, only to reappear within one year. Physical model tests at high open water flows and large gate openings failed to reproduce scour observed in prototype. It was then speculated that ice could be a factor. Further model tests with a 3-m-thick artificia l cover did result in scour upstream of the piers and gates. That ice might govern the bed protection design at major r iver structures in the US had previously not been considered. This paper describes preliminary research to better understand ice related scour processes at large navigat ion dams. The study uses numerical and physical model invest igat ions of ice-hydraulic scour processes to find a long term so lut ion to the Mel Price scour problem and also develop design guidance to avoid similar failures at new projects.
Year: 2010