Seismic Behavior of Bidirectional-Resistant Ductile End Diaphragms with Unbonded Braces in Straight or Skewed Steel Bridges

Since end diaphragms of many bridges in North America were built without seismic design considerations, they may suffer damage in future earthquakes. Recent earthquake reconnaissance investigations have reported damage in bridge end diaphragms due to earthquake effects. To reduce the seismic demands in steel bridges, one approach (among many such as base isolators of any king) is to provide bridge superstructures with special ductile diaphragms as “seismic fuses” as an appropriate retrofit solution. Although the behavior of metallic fuses in the bridge transverse direction has been investigated both analytically and experimentally under unidirectional loading, no guidance exists to help the engineer determine the seismic behavior under bidirectional loading. Furthermore, to date, the ductile diaphragm concepts were limited in recommended applications to the retrofit of regular (i.e. non-skewed) bridges and this solution thus has to be combined with another retrofit solution for resistance to earthquakes exciting bridges in their longitudinal direction. This research mainly aims to extend the known ductile end diaphragm concept to make it applicable for bidirectional earthquake excitation, using unbonded braces as the ductile fuses. Irregular (i.e. skewed) bridge superstructure are also covered to determine if the ductile diaphragm concept could be used in skewed bridges. Two retrofit schemes (Retrofit Scheme-1 and Retrofit Scheme-2) are investigated in detail to search the best geometrical layout (to maximize the dissipated hysteretic energy) of the ductile diaphragms with unbonded brace end diaphragms. Closed form solutions are sought for practical design purposes.

  • Corporate Authors:

    Multidisciplinary Center for Earthquake Engineering Research

    State University of New York, 107 Red Jacket Quadrangle, P.O. Box 610025
    Buffalo, NY  United States  14261-0025

    Federal Highway Administration

    1200 New Jersey Avenue, SE
    Washington, DC  United States  20590
  • Authors:
    • Celik, Oguz C
    • Bruneau, Michel
  • Publication Date: 2007-4-11

Language

  • English

Media Info

  • Media Type: Print
  • Edition: Technical Report
  • Features: Figures; Photos; References; Tables;
  • Pagination: 177p

Subject/Index Terms

Filing Info

  • Accession Number: 01076721
  • Record Type: Publication
  • Report/Paper Numbers: MCEER-07-0003
  • Contract Numbers: DTFH61-98-C-00094
  • Files: TRIS, USDOT
  • Created Date: Sep 10 2007 4:39PM