Type N PTFE Bearing Designs

Missouri Department of Transportation (MoDOT) currently specifies filled or unfilled flat PTFE bearings per section 1038.4.4 for expansion bearings. The design friction coefficients are in EPG section 751.50. MoDOT believes that if designers follow their specifications, then the filled PTFE and/or cold values may be conservatively used but that it leads to friction forces that are sizable. The dynamic friction force is often larger than the forces that would be applied to a fixed bent due to temperature, wind, or braking. This nullifies the benefits of using the expansion bearing. This research will look at what design coefficients of friction should be used when distributing forces for substructure design. The research will also determine if dimpled lubricated pads are an effective alternate and if so, what should be added to the specs to address maintenance issues with this type of bearing.


    • English


    • Status: Active
    • Funding: $200,000
    • Contract Numbers:


    • Sponsor Organizations:

      Missouri Department of Transportation

      1617 Missouri Boulevard
      P.O. Box 270
      Jefferson City, MO  United States  65102
    • Project Managers:

      Harper, Jennifer

    • Performing Organizations:

      Wiss, Janney, Elstner Associates, Incorporated

      330 Pfingsten Road
      Northbrook, IL  United States  60062
    • Principal Investigators:

      McGormley, Jonathan

    • Start Date: 20221115
    • Expected Completion Date: 20240531
    • Actual Completion Date: 0

    Subject/Index Terms

    Filing Info

    • Accession Number: 01875338
    • Record Type: Research project
    • Source Agency: Missouri Department of Transportation
    • Contract Numbers: TR202204
    • Files: RIP, STATEDOT
    • Created Date: Mar 10 2023 11:05AM