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.

• Record URL:
  http://www.pooledfund.org/Details/Study/482

Language

• English

Project

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

  TPF-5(253)

• 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

• TRT Terms: Bridge members; Fracture mechanics; Inspection; Load and resistance factor design; Redundancy
• Uncontrolled Terms: Load carrying capacity
• Subject Areas: Bridges and other structures; Highways; Maintenance and Preservation;

Filing Info

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