Reducing Flood Vulnerability of Communities with Limited Road Access by Optimizing Bridge Elevation

On September 11-17, 2013, Colorado suffered devastating and widespread flash flooding over 150 miles from Colorado Springs north to Fort Collins, impacting 24 counties. The flood damaged several bridges and over 400 miles of state roads. As a result of the transportation damage, residents of Drake, Colorado, were isolated and had to be evacuated via helicopter. This thesis aims to determine the failure risk associated with the inundation of bridge superstructures. A linear network of eight bridges near Drake, Colorado, was selected for analysis, which includes three unique structural configurations. Flood analysis was performed using the design equations presented by Kerenyi et al. (2009), which follows the same equation format listed in American Association of State Highway and Transportation Officials (AASHTO). Fragilities were developed for the most critical internal and external composite girders for each bridge. The results obtained from fragility analysis were then used to determine the elevation adjustments needed to reach a target beta value of 3.5. Based on the analysis conducted in this thesis, it was found that the forces associated with bridge deck inundation, more specifically, in fast-moving mountain rivers is substantial and must be considered in design. Currently, bridge superstructures are designed based on the 100-year flood, which in the case of the bridges in this study, would not have resulted in any inundation of the bridge deck at the time of construction based on the knowledge at that time. To counter this, bridge superstructures should be designed based on the 500-year flood, which would incorporate inundation forces in the initial design. The methodology presented in this thesis can be used to assess and improve the flood vulnerability for any communities’ bridge network.

  • Record URL:
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  • Supplemental Notes:
    • This document was sponsored by the U.S. Department of Transportation, University Transportation Centers Program.
  • Corporate Authors:

    Colorado State University, Fort Collins

    Department of Civil and Environmental Engineering
    Fort Collins, CO  United States  80525

    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
  • Authors:
    • Turner, David
    • van de Lindt, John W
    • Senior, Bolivar
  • Publication Date: 2020-10


  • English

Media Info

  • Media Type: Digital/other
  • Features: Appendices; Figures; Photos; References; Tables;
  • Pagination: 153p

Subject/Index Terms

Filing Info

  • Accession Number: 01763113
  • Record Type: Publication
  • Report/Paper Numbers: MPC-20-423
  • Contract Numbers: MPC-448
  • Created Date: Feb 3 2021 2:22PM