Development of New Design Guidelines for Protection Against Erosion at Bridge Abutments - Phase III

The present research proposes the use of a numerically-based approach to develop improved design formulas for minimum riprap stone size for protection against erosion of spill-through abutments. Spill-through abutments are very common at small bridges where abutments are placed on the floodplain. The mean flow fields predicted using fully 3-D RANS simulations are used to estimate the maximum bed shear stress over the riprap layer and the critical Froude number corresponding to the shear-failure entrainment threshold for the riprap stone. During the first year, the numerically-based approach was validated for the case of wing-wall abutments placed in a straight channel. During the second year, a new two-parameter formula was proposed for riprap design at wing-wall abutments. The new formula accounts for the influence of the nondimensional floodplain width and radius of curvature of the channel on the critical Froude number at which riprap shear failure occurs. During the third year, a comprehensive parametric study will be conducted that will provide the data needed to understand how channel curvature, floodplain width and relative length of the spill-through abutment influence the peak bed shear stress over the riprap regions. The main goal will be to develop a multi-parameter formula for riprap design at spill-through abutments placed in straight and curved channels as a function of the nondimensional floodplain width, ratio of abutment length to floodplain width, nondimensional riprap stone size and radius of curvature of the channel. These series of simulations will also allow better understanding the limitations of presently available riprap design formulas proposed for spill-through abutments placed in straight channels and the performance of the Set Back Ratio formula used to estimate the velocity in the critical Froude number. Recommendations will be made for inclusion of the new design formula in future versions of HEC-23.

• Record URL:
  https://matc.unl.edu/research/research_project.php?researchID=575

Language

• English

Project

• Status: Completed
• Funding: $149751
• Contract Numbers:

  69A3551747107

• Sponsor Organizations:

  Mid-America Transportation Center

  University of Nebraska-Lincoln
  2200 Vine Street, PO Box 830851
  Lincoln, NE  United States  68583-0851

  Office of the Assistant Secretary for Research and Technology

  University Transportation Centers Program
  Department of Transportation
  Washington, DC  United States  20590
• Managing Organizations:

  Mid-America Transportation Center

  University of Nebraska-Lincoln
  2200 Vine Street, PO Box 830851
  Lincoln, NE  United States  68583-0851
• Performing Organizations:

  University of Iowa, Mechanical and Industrial Engineering

  3100 Seamans Center for the Engineering Arts and Sciences
  Iowa City, Iowa  United States  52242
• Principal Investigators:

  Constantinescu, George

• Start Date: 20191213
• Expected Completion Date: 20201231
• Actual Completion Date: 20200831
• USDOT Program: University Transportation Centers Program
• Source Data: RiP Project 91994-47

Subject/Index Terms

• TRT Terms: Bridge abutments; Erosion control; Flood plains; Froude number; Guidelines; Riprap; Shear stress; Simulation; Validation
• Subject Areas: Bridges and other structures; Design; Highways; Hydraulics and Hydrology;

Filing Info

• Accession Number: 01736244
• Record Type: Research project
• Source Agency: Mid-America Transportation Center
• Contract Numbers: 69A3551747107
• Files: UTC, RIP
• Created Date: Apr 16 2020 4:03PM