Flood Hydrograph Generation for Predicting Bridge Scour in Cohesive Soils

Three bridge sites in South Dakota with streamflow records ranging from 50 to 67 years were selected to compute the histories of pier or contraction scour using the Scour Rates In COhesive Soils (SRICOS) method. Scour depths were computed using a range of soil erosion functions representative of cohesive and non-cohesive soils. The results show that a continuous hydrograph spanning several decades may be replaced by a series of maximum annual floods. A tiered approach for using the SRICOS method was developed. In the Level I analysis, the results of soil classification or soil erosion rate testing are used with simple calculations to eliminate bridge sites where use of the SRICOS method is not recommended. In the Level II analysis, recorded hydrographs are used to predict the final scour depths produced by floods of different return periods to assess scouring potential. In the Level III analysis, annual maximum series are generated and used with the SRICOS method to compute the exceedance probabilities associated with different scour depths and project lives. Each flood in the annual maximum series has a constant discharge sampled randomly from the Log Pearson Type III (LP-III) distribution and an equivalent duration computed using a regression equation.

• Record URL:
  https://www.ugpti.org/resources/reports/details.php?id=1082
• Record URL:
  https://rosap.ntl.bts.gov/view/dot/63026
• Supplemental Notes:
  • This document was sponsored by the U.S. Department of Transportation, University Transportation Centers Program.
• Corporate Authors:

  South Dakota State University, Brookings

  Department of Civil and Environmental Engineering
  Brookings, SD  United States  57007

  Mountain-Plains Consortium

  North Dakota State University
  Fargo, ND  United States  58108

  Office of the Assistant Secretary for Research and Technology

  University Transportation Centers Program
  Department of Transportation
  Washington, DC  United States  20590

  South Dakota Department of Transportation

  700 East Broadway Avenue
  Pierre, SD  United States  57501
• Authors:
  • Ting, Francis C K
  • Kidd, Brian
• Publication Date: 2022-5

Language

• English

Media Info

• Media Type: Digital/other
• Features: Appendices; Figures; Photos; References; Tables;
• Pagination: 246p

Subject/Index Terms

• TRT Terms: Bridges; Cohesive soils; Flood hydrographs; Forecasting; Scour
• Geographic Terms: South Dakota
• Subject Areas: Bridges and other structures; Highways; Hydraulics and Hydrology; Planning and Forecasting;

Filing Info

• Accession Number: 01853349
• Record Type: Publication
• Report/Paper Numbers: MPC-22-459
• Contract Numbers: MPC-531
• Files: UTC, NTL, TRIS, ATRI, USDOT, STATEDOT
• Created Date: Jul 29 2022 9:17AM