Repair and Retrofit of Concrete Bridge Girders Using Hybrid FRP Sheets

The use of carbon fibers (CF) and glass fibers (GF) were combined to strengthen potentially non-ductile flexural members. Based on tension tests of fiber-reinforced polymer (FRP) rovings and sheets, as well as theoretical research on hybrid FRP, a volume ratio of (GF/CF) was determined to be about (8.8/1) to produce synergistic hybrid effects and pseudo-ductility. The (8.8/1) ratio was used to fabricate hybrid carbon-glass FRP sheets, and this optimal combination was verified through four-point loading tests of plain and reinforced concrete beams strengthened with single or multiple plies of FRP sheets. The increased flexural strengths were evaluated using available design procedures in conjunction with a proposed force-strain relationship for hybrid carbon-glass FRP sheets. Additionally, data of tensile tests of 94 hybrid carbon-glass FRP sheets and 47 carbon and glass fiber rovings or sheets were thoroughly re-examined in terms of tensile behavior. Based on thorough comparisons between the rule of mixtures for fibrous composites and test data, positive hybrid effects were clearly identified for almost all (GF/CF) ratios. In contrast to the rule of mixtures, the hybrid sheets with relatively low (GF/CF) ratios also produced pseudo-ductility. From the calibrated results obtained from experiments, a novel analytical model for the stress-strain relationship of hybrid FRP sheets was proposed. The effect of various epoxy resins, impregnating degree and specimen grips on the tensile behavior was minimal.

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

    University of Oklahoma, Norman

    School of Civil Engineering and Environmental Science, 202 West Boyd Street
    Norman, OK  United States  73019

    Oklahoma Transportation Center

    2601 Liberty Parkway, Suite 110
    Midwest City, OK  United States  73110

    Research and Innovative Technology Administration

    1200 New Jersey Avenue, SE
    Washington, DC  United States  20590
  • Authors:
    • Kang, Thomas H-K
    • Kim, Woosuk
    • Hufnagel, Amy
    • Ibrahim, Moustapha Ary
    • Huang, Yu
    • Choi, Dong-Uk
    • Lee, Chin Yong
    • Holliday, Lisa
  • Publication Date: 2012-2


  • English

Media Info

  • Media Type: Digital/other
  • Edition: Final Report
  • Features: Figures; Photos; References; Tables;
  • Pagination: 83p

Subject/Index Terms

Filing Info

  • Accession Number: 01494505
  • Record Type: Publication
  • Report/Paper Numbers: OTCREOS10.1-21-F
  • Contract Numbers: DTRT06-G-0016 (Grant)
  • Created Date: Sep 26 2013 1:29PM