TENTATIVE DESIGN PROCEDURE FOR RIPRAP-LINED CHANNELS

THE MOST EXTENSIVELY USED PROTECTIVE LININGS FOR ROADSIDE DITCHES CURRENTLY ARE TURF COVER, EITHER BY SODDING OR OTHER METHODS OF ESTABLISHMENT, AND VARIOUS TYPES OF PAVEMENT. THESE LININGS ARE QUITE EFFECTIVE FOR A WIDE VARIETY OF CONDITIONS BUT HAVE CERTAIN LIMITATIONS, SUCH AS (1) TURF COVER IS VERY DIFFICULT TO ESTABLISH IN ARID AREAS AND OVER SANDY SOIL, (2) TURF COVER IS ONLY EFFECTIVE AT RELATIVELY LOW FLOW VELOCITIES, (3) PAVED DITCH LININGS ARE USUALLY DIFFICULT TO CONSTRUCT AND RATHER COSTLY, AND (4) PAVED DITCH LININGS AT TIMES REQUIRE EXTENSIVE MAINTENANCE DUE TO UNDERCUTTING. AS A RESULT, THERE IS A NEED FOR A TYPE OF ECONOMICAL PROTECTIVE LINING FOR ROADSIDE CHANNELS SUITABLE FOR CONDITIONS INTERMEDIATE BETWEEN THOSE FOR WHICH TURF COVER PERFORMS SATISFACTORILY AND THOSE FOR WHICH PAVED CHANNELS OR PIPE FLUMES ARE MORE ECONOMICAL. THE OBJECTIVE OF THIS STUDY WAS THE DEVELOPMENT OF CRITERIA AND DESIGN PROCEDURES FOR THE USE OF AGGREGATE RIPRAP LININGS, WHICH CONSISTS OF A LAYER OF DISCRETE FRAGMENTS OF ROCK OF SUFFICIENT SIZE TO RESIST THE EROSIVE FORCES OF THE FLOW. THE DESIGN OF SUCH RIPRAP-LINED DRAINAGE CHANNELS INVOLVES THE INTERRELATIONSHIP BETWEEN THE DISCHARGE, THE LONGITUDINAL SLOPE, THE SIZE AND SHAPE OF THE CHANNEL, AND THE SIZE DISTRIBUTION OF THE RIPRAP LINING. THIS REPORT DESCRIBES THESE INTERRELATIONSHIPS AND DEVELOPS DESIGN CRITERIA BY WHICH A RIPRAP-LINED DRAINAGE CHANNEL CAN BE PROPORTIONED AND THE RIPRAP LINING CAN BE SPECIFIED FOR A GIVEN DISCHARGE AND LONGITUDINAL SLOPE. THE RELATIONSHIPS SO DEVELOPED HAVE BEEN REDUCED TO DESIGN CHARTS, THE USE OF WHICH PERMITS RAPID AND SIMPLE ESTABLISHMENT OF CHANNEL SHAPE AND SIZE AS WELL AS OF THE PROPERTIES OF THE RIPRAP LINING. HIGHWAY DRAINAGE CHANNELS ARE DIVIDED INTO TWO GROUPS. IN THE FIRST GROUP ARE THOSE THAT SERVE AS MEDIAN OR SIDE DITCHES FOR THE DRAINAGE OF THE ROADWAYS. THESE ARE RELATIVELY SMALL AND OFTEN APPROACH A TRIANGULAR CROSS SECTION BECAUSE OF THE RELATIVELY FLAT SIDE SLOPES AND GENERALLY SMALL BOTTOM WIDTH. IN THE SECOND GROUP ARE LARGE DRAINAGE CHANNELS THAT CONVEY A LARGER DISCHARGE AND ARE USUALLY TRAPEZOIDAL IN CROSS SECTION. A SET OF DESIGN CHARTS FOR EACH TYPE HAS BEEN PREPARED. LIMITED EXPERIMENTAL DATA ARE PRESENTED WHICH SERVE TO VERIFY THE DESIGN PROCEDURE, TO TEST THE EFFICACY OF CHANNELS DESIGNED ACCORDING TO THIS PROCEDURE, AND TO EXAMINE SOMEWHAT MORE CLOSELY THE PHENOMENON OF LEACHING OF BASE MATERIAL THROUGH THE RIPRAP INTERSITES. THESE EXPERIMENTS, ALTHOUGH PRELIMINARY IN CHARACTER, INDICATE THAT THE DESIGN PROCEDURES ARE SUITABLE AND INCORPORATE SUFFICIENTLY LARGE FACTORS OF SAFETY TO PROVIDE STABLE CHANNELS. /AUTHOR/

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    • 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. Originally published as NCHRP Research Results Digest, No. 1, December 1968, which was superseded by this report.
  • Authors:
    • Anderson, A G
    • Paintal, A S
    • Davenport, J T
  • Publication Date: 1970

Media Info

  • Media Type: Digital/other
  • Pagination: 175 p.
  • Serial:
    • NCHRP Report
    • Issue Number: 108
    • Publisher: Transportation Research Board
    • ISSN: 0077-5614
  • Publication flags:

    Open Access (libre)

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Filing Info

  • Accession Number: 00204326
  • Record Type: Publication
  • Files: TRIS, ATRI
  • Created Date: Apr 18 1971 12:00AM