Seismic Behavior of Steel Bridges with Fatigue-prone Details

Steel bridges (with reinforced concrete substructures and steel superstructures) are generally considered to have a superior performance under earthquakes when compared to their reinforced concrete counterpart. Such performance reputation stems from the fact that few steel bridges have been subjected to strong ground motion in the last decade in North America as opposed to the inherent capacity of the bridges. In addition to the lack of seismic exposure of the bridges, research on the seismic performance of steel bridges' superstructure is limited to a handful of studies. Noteworthy that none of the previously conducted studies addressed the behavior of fatigue details in the bridge superstructure, which are designed for traffic loading, under earthquake loading. In the superstructure, fatigue is often the most prevalent problem, which contributes to approximately 90% of existing cracks. The cracks are a result of the repeated traffic cycles that are exerted on the bridge (fatigue cracks under traffic loads are termed high-cycle fatigue). For existing bridges, achieving satisfactory fatigue performance under traffic loading requires correct identification of the fatigue-prone details, coupled with well-planned inspection routines and the implementation of effective repairs. For existing bridges, the most recent changes to code design procedures and guidelines have proven to greatly minimize or even eliminate the main fatigue concerns. Designing a new bridge superstructure and/or retrofitting an existing bridge to alleviate present fatigue cracks accounts only for traffic loading. The performance of the fatigue-prone details, designed for service loads, under earthquake ground motions demand is yet to be investigated. The objectives of this research project are to: (1) Conduct literature review on the fatigue performance of steel bridge' superstructures under seismic loading. (2) Conduct analytical studies to assess the low and ultra-low cycle fatigue life of the details in question and evaluate if current high-cycle design and retrofit methodologies are effective for seismic loading. (3) Provide practical guidelines for retrofitting existing fatigue prone details to withstand seismic demand.

Language

  • English

Project

  • Status: Active
  • Funding: $92000
  • Contract Numbers:

    DTRT12-G-UTC08

  • Sponsor Organizations:

    Research and Innovative Technology Administration

    University Transportation Centers Program
    1200 New Jersey Avenue
    Washington, DC  United States  20590
  • Project Managers:

    Kline, Robin

  • Performing Organizations:

    Colorado State University, Fort Collins

    Fort Collins, CO  United States  80523
  • Principal Investigators:

    Mahmoud, Hussam

  • Start Date: 20120101
  • Expected Completion Date: 20161231
  • Actual Completion Date: 0
  • Source Data: MPC-382

Subject/Index Terms

Filing Info

  • Accession Number: 01483282
  • Record Type: Research project
  • Source Agency: Mountain-Plains Consortium
  • Contract Numbers: DTRT12-G-UTC08
  • Files: UTC, RiP
  • Created Date: Jun 6 2013 1:02AM