Evaluation of SRICOS Method on Cohesive Soils in South Dakota

The SRICOS (Scour Rates In COhesive Soils) method had been proposed as an alternative design methodology for predicting scour at bridges founded in cohesive soils. As the new method can produce substantial savings in bridge construction costs at cohesive soil sites, it is important that South Dakota Department of Transportation (SDDOT) evaluates the method carefully for use in bridge design. This research project compared the predictions of the SRICOS method for pier scour with measured scour at three bridge sites in South Dakota and examined the technical issues involved in using the method. The research began with an assessment of the SRICOS method and a survey of current practice in evaluating bridges for scour used by other State DOTs. Three bridge sites in South Dakota were selected to evaluate the method for pier scour. Subsurface exploration, laboratory testing, hydraulic modeling, and hydrologic analysis were performed for each site to generate the inputs for computing scour using the SRICOS method. The computed scour depths were compared to the measured scour obtained by the United States Geological Survey (USGS) in 1991-1993 when a number of large floods occurred at the study sites. To provide a scale for the comparison, a sensitivity analysis was performed for each site to determine the sensitivity in the computed scour depth to the input parameters. The site-specific sensitivity analyses were complemented by a non site-specific sensitivity analysis to identify and rank the critical input parameters. A method to use the SRICOS method to predict bridge scour in watersheds where streamflow records are not available was proposed. This report recommends that SDDOT: (1) use the SRICOS method as a supporting tool in evaluating bridges for scour, (2) continue to monitor current and future research to observe new improvements, (3) conduct workshops to train design engineers in using the method; (4) acquire testing equipment to measure soil erodibility; (5) establish a procedure for collecting scour data immediately after major floods to verify future improvements; and (6) conduct research to improve predictions of hydraulics of bridge waterways and the effect of large floods on time rate of scour.

• Record URL:
  https://www.ugpti.org/resources/reports/details.php?id=642
• 
• Supplemental Notes:
  • This document is disseminated under the sponsorship of the Department of Transportation, University Transportation Centers Program.
• Corporate Authors:

  South Dakota State University, Brookings

  Department of Civil and Environmental Engineering
  P.O. Box 2219
  Brookings, SD  United States  57007

  Mountain-Plains Consortium

  North Dakota State University
  Fargo, ND  United States  58108

  Research and Innovative Technology Administration

  Office of University Programs, 1200 New Jersey Avenue, SE
  Washington, DC  United States  20590
• Authors:
  • Ting, Francis C K
  • Jones, Allen L
  • Larsen, Ryan J
• Publication Date: 2010-1

Language

• English

Media Info

• Media Type: Digital/other
• Edition: Final Report
• Features: Figures; References; Tables;
• Pagination: 235p

Subject/Index Terms

• TRT Terms: Bridge design; Cohesive soils; Hydraulics; Scour
• Geographic Terms: South Dakota
• Subject Areas: Highways; Hydraulics and Hydrology; I26: Water Run-off - Freeze-thaw;

Filing Info

• Accession Number: 01155069
• Record Type: Publication
• Report/Paper Numbers: MPC Report No. 08-195
• Files: UTC, TRIS, USDOT
• Created Date: Apr 22 2010 7:47AM