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Mid-America Transportation Center

NDOR Impact of Large 0.7 Inch Strand on NU-I Girders

Final Report
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Researchers

  • Principal Investigator: Maher Tadros (mtadros1@unl.edu 4025544842)
  • Project Status
    Complete
    Sponsors & Partners
  • Nebraska Department of Roads
  • Research Objective
    The objective of this project is to develop the quality control and design criteria required to introduce 0.7 inch strands at 2 in. spacing in NU I-Girders
    Potential Benefits
    Reducing the number of strands would result in immediate labor savings in precast concrete product costs. Having the ability to introduce almost twice the prestressing force could result in a significant increase in the span capacity of the current Nebraska Department of Roads (NDOR) NU I Girder without having to modify the sections or acquire new forms.
    Abstract
    The NU I-Girder series uses a unique cross-section and high-strength concrete to achieve longer spans. The objective of this project is to develop the quality control and design criteria required to introduce 0.7 inch strands at 2 in. spacing in NU I-Girders. Compared to 0.5 inch strands, only 1/2 of the total number of strands would be needed. This would result in immediate labor savings in precast concrete product costs. More importantly, having the ability to introduce almost twice the prestressing force, compared to 0.5 inch strand and 135% of the prestressing force, compared to 0.6 inch strand, could result in a significant increase in the span capacity of the current Nebraska Department of Roads (NDOR) NU I Girder without having to modify the sections or acquire new forms.
    Project Amount
    $ 244,408