Member-level Redundancy in Built-up Steel Members

The Federal Highway Administration (FHWA) currently has the authority to allow owners to forego fracture-critical inspection for low redundancy bridge structures on a case-by-case basis if supported by a rigorous damage analysis as per American Association of State Highway & Transportation Officials Load and Resistance Factor Design (AASHTO LRFD). However, since there is limited experimental data specifically focused on this issue, using internal redundancy as the sole measure of redundancy cannot be approved by FHWA at this time. Hence, specific research is needed that can be used to evaluate the potential for a fracture propagating from one mechanically fastened element to another in a built-up member as well as the effects on the fatigue resistance of the faulted member. Furthermore, there is no known research that has quantified the energy release (and resulting loads on the remaining section) that is likely to occur during such a fracture event. This project will explore whether internally redundant members (either mechanically fastened built-up members, or those with parallel elements) do posses the internal arrest mechanisms to safely carry loads during and after a fracture event considering one of multiple elements are fractured. The project will be primarily based on full-scale specimens subjected to various fracture simulations for the purposes of gaining deeper understanding of the energy release, load redistribution, and subsequent fatigue resistance of damaged section. However, analytical studies will also be conducted to assist in the development of code-ready assessment methodologies. The project will also assess the role of inspection technique and frequency for internally redundant members considering the research may show they do not fit the AASHTO definition of fracture-critical. Obtaining experimental data in a controlled fashion will provide the needed evidence to establish if internal member redundancy is a reliable redundancy measure to use for collapse prevention in a fracture-critical assessment. This will improve the ability to properly allocate limited bridge inspection resources and improve overall safety of the nation's infrastructure.


  • English


  • Status: Completed
  • Funding: $600000
  • Contract Numbers:


  • Sponsor Organizations:

    Federal Highway Administration

    1200 New Jersey Avenue, SE
    Washington, DC  United States  20590

    Iowa Department of Transportation

    800 Lincoln Way
    Ames, IA  United States  50010

    Minnesota Department of Transportation

    Transportation Building
    395 John Ireland Boulevard
    St Paul, MN  United States  55155

    Oregon Department of Transportation

    355 Capitol St. NE
    Salem, OR  United States  97301-3871

    Wisconsin Department of Transportation

    PO Box 7910
    4802 Sheboygan Avenue, Room 104
    Madison, WI  United States  53707-7910

    Wyoming Department of Transportation

    5300 Bishop Boulevard
    Cheyenne, WY  United States  82009-3340

    New York State Department of Transportation

    50 Wolf Road
    Albany, NY  United States  12232

    Army Corps of Engineers

  • Project Managers:

    Nantung, Tommy

  • Start Date: 20110802
  • Expected Completion Date: 0
  • Actual Completion Date: 20180630
  • Source Data: RiP Project 29834

Subject/Index Terms

Filing Info

  • Accession Number: 01566840
  • Record Type: Research project
  • Source Agency: Federal Highway Administration
  • Contract Numbers: TPF-5(253)
  • Created Date: Jun 23 2015 1:02AM