SCOUR AT SELECTED BRIDGE SITES IN ALASKA
General scour at bridge crossings and local scour at bridge piers were measured at nine bridge sites in Alaska during the study period 1965-72. A detailed description of the physical setting, hydraulic characteristics, and channel geometry at low and high flows is given for each site to assist the reader in developing a background for the scour phenomenon in various situations. Flood discharges, during which scour data were collected, had recurrence intervals which range from approximately two years at some sites to about 100 years on the Tanana River at Nenana. General scour was minimal at crossings with no channel contraction. Measured general scour in contracted openings at three sites indicated mean depth of flow in contracted openings can be calculated by two established scour formulas to within 10% of the actual mean depth. Measured local equilibrium scour depth and bed material sizes at bridge piers were used to modify an existing pier scour formula to estimate maximum local equilibrium scour depth at round or pointed-nosed piers alined with the flow. The data suggest local equilibrium scour depth at piers during a mean annual flood is approximately as great as that which occurs during floods of greater magnitude.
- Prepared in cooperation with Alaska State Dept. of Highways, Juneau, and Federal Highway Administration, Washington, D.C. Report on Water-resources Investigations.
U.S. Geological SurveyF Street Between 18th and 19th Street, NW
Washington, DC 20244
Washington, DC United States 20590
Juneau, AK United States 99801
- Norman, V W
- Publication Date: 1975-11
- Features: Figures; Tables;
- Pagination: 171 p.
- TRT Terms: Bridge piers; Bridges; Calculation; Channel flow; Channels (Waterways); Design; Floods; Flow; Fluid dynamics; Formulas; Highway bridges; Hydraulics; Loads; Location; Loss and damage; Piers (Supports); Piers (Wharves); Pile foundations; Rivers; Scour; Sedimentation; Streams
- Uncontrolled Terms: Building sites; Computation; Fluid flow; Open channel flow; Sediment transport; Stream channels
- Geographic Terms: Alaska
- Old TRIS Terms: Bed load; Flow channel
- Subject Areas: Bridges and other structures; Design; Highways; Hydraulics and Hydrology;
- Accession Number: 00093956
- Record Type: Publication
- Source Agency: National Technical Information Service
- Report/Paper Numbers: USGS-WRD-76-001 Final Rpt., USGS-WRI-32-75
- Files: NTIS, TRIS, USDOT, STATEDOT
- Created Date: Mar 10 1976 12:00AM