The design modifications that have been developed in response to the problems that have arisen in the two years since breakaway cable terminals (BCT) were first developed are summarized. It was found that placing sheet metal around the post before casting the footing proved to be a workable solution in dealing with the problem of removing broken wood posts. Also, static tests have shown that an 8 x 8 x 5/8 inch bearing plate is more than adequate for transferring the load from the anchor cable to the post, thus eliminating the need for some of the more expensive anchorage components that have been used. A breakaway steel-post foundation system utilizing a box beam and bearing plate has been developed to eliminate the need for the concrete footings which are too expensive for use in rural locations. Because subcompact vehicles had been snagging the stub remaining after the foundation post's breaking away, the foundation post was redesigned as to have minimal projection above grade. Furthermore, tests have reconfirmed the importance of the 4-foot offset flare that had been included in the original guardrail design recommendations but which are not yet required in several state standards.

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  • Supplemental Notes:
    • Distribution, posting, or copying of this PDF is strictly prohibited without written permission of the Transportation Research Board of the National Academy of Sciences. Unless otherwise indicated, all materials in this PDF are copyrighted by the National Academy of Sciences. Copyright © National Academy of Sciences. All rights reserved.
  • Corporate Authors:

    Transportation Research Board

    500 Fifth Street, NW
    Washington, DC  United States  20001
  • Authors:
    • Bronstad, M E
    • Michie, J D
  • Publication Date: 1978-5

Media Info

  • Media Type: Digital/other
  • Features: Figures; References; Tables;
  • Pagination: 13 p.
  • Serial:
  • Publication flags:

    Open Access (libre)

Subject/Index Terms

Filing Info

  • Accession Number: 00178215
  • Record Type: Publication
  • Files: TRIS, TRB
  • Created Date: Jul 19 1978 12:00AM