Geotechnical Limit to Scour at Spill-through Bridge Abutments: Laboratory Investigation

Scour of spill-through abutments occurs due to the combined influence of geotechnical and hydraulic processes. The present study is among the first to address the geotechnical process associated with the failure of the compacted earth, spill-through abutments, and the effects of the geotechnical strength of spill-slope soil on abutment scour. Laboratory experiments were completed to determine how soil shear strength affects abutment scour. The experiments, which primarily involved sand compacted to varying strengths, and some clayey soils, led to new and useful insights. A major new finding is that abutment failure begins at the water line of the spill-slope's upstream corner, where flow constriction around an abutment exposes and erodes spill-slope soil to the highest values of flow velocity and turbulence. Once initiated, erosion continues toward the middle portion of the spill-slope face, and then progresses downstream. Spill-slope erosion is marked by the formation of undercut, exposed vertical blocks of embankment soil whose failure occurred relatively quickly once the spill-slope face began eroding. Abutments formed of stronger soils took longer to erode, had bigger blocks of failed soil, and produced deeper scour of the channel around the abutment. Rapid failure of an abutment resulted in shallow scour depths.

• Record URL:
  • https://www.ugpti.org/resources/reports/details.php?id=791
• 
• Supplemental Notes:
  • This document was sponsored by the U.S. Department of Transportation, University Transportation Centers Program.
• Corporate Authors:

  University of Wyoming, Laramie

  Department of Civil and Architectural Engineering
  1000 East University Avenue
  Laramie, WY  United States  82071

  Mountain-Plains Consortium

  North Dakota State University
  Fargo, ND  United States  58108

  Research and Innovative Technology Administration

  1200 New Jersey Avenue, SE
  Washington, DC  United States  20590
• Authors:
  • Ng, Kam
  • Ettema, Robert
  • Kempema, Edward
  • Chakradhar, Ram
  • Fuller, Joshua
• Publication Date: 2015-3

Language

• English

Media Info

• Media Type: Digital/other
• Features: Figures; Photos; References; Tables;
• Pagination: 90p

Subject/Index Terms

• TRT Terms: Bridge abutments; Embankments; Erosion; Laboratory tests; Scour; Shear strength; Slope stability; Soil mechanics
• Subject Areas: Bridges and other structures; Geotechnology; Highways; Hydraulics and Hydrology; I26: Water Run-off - Freeze-thaw; I42: Soil Mechanics;

Filing Info

• Accession Number: 01560977
• Record Type: Publication
• Report/Paper Numbers: MPC-15-280
• Contract Numbers: MPC-354
• Files: UTC, TRIS, RITA, ATRI, USDOT
• Created Date: Apr 24 2015 10:24AM