92-5F PERFORMANCE OF SINGLE & DOUBLE SILLS FOR STEEP CIRCULAR CULVERTS

THE HYDRAULIC PERFORMANCE OF STEEP SLOPED CIRCULAR CULVERTS IS INVESTIGATED EXPERIMENTALLY BY USING 18- INCH DIAMETER CORRUGATED METAL AND CONCRETE PIPE CULVERT MODELS OF DIFFERENT GEOMETRICAL CONFIGURATIONS. ONE OF THE EFFECTIVE MEANS TO DISSIPATE THE ENERGY OF SUPERCRITICAL FLOWS IN STEEP CULVERTS IS TO FORCE A HYDRAULIC JUMP TO THE INSIDE OF THE CULVERT PIPE BY PLACING A SILL WITHIN THE FLARED WINGWALLS OF THE CULVERT. ALTHOUGH SOME AMOUNT OF ENERGY IS DISSIPATED BY THE JUMP, THERE STILL REMAINS THE PROBLEM OF HIGH VELOCITY CONCENTRATIONS IN THE CENTRAL REGION OF THE DOWNSTREAM CHANNEL FOLLOWING THE NAPPE FROM THE JUMP PRODUCING SILL. THE USE OF TWO SILLS IN SUCH CASES WOULD ACCOMPLISH MORE ENERGY DISSIPATION DUE TO THE FACT THAT THE ENERGY OF THE NAPPE IS DISSIPATED IN THE POOL CREATED BY THE SECOND SILL. FURTHERMORE, THE FLOW IS DISTRIBUTED IN THE DOWNSTREAM CHANNEL MORE EVENLY IN A SHORTER DISTANCE. THE PRIMARY OBJECTIVES ARE TO DETERMINE THE HEIGHT AND LOCATION OF THE JUMP PRODUCING SILL FOR DIFFERENT CULVERT GEOMETRIES OVER A BROAD RANGE OF DISCHARGE FACTORS AND ALSO TO DETERMINE THE BEST DOUBLE SILL CONFIGURATION THAT WOULD CURTAIL THE EXTENT OF SUPERCRITICAL STATE OF FLOW IN THE DOWNSTREAM CHANNEL. DATA WERE COLLECTED ON WATER SURFACE PROFILES, JUMP LOCATIONS WITHIN THE CULVERT PIPE, TRANSVERSE DEPTH AND VELOCITY PROFILES IN THE DOWNSTREAM CHANNEL, HEAD WATER DEPTHS FOR VARIOUS DISCHARGE FACTORY RANGING UP TO A MAXIMUM VALUE OF 6.5 AND FOR DIFFERENT CULVERT GEOMETRIES. THE MEASURED WATER SURFACE PROFILES AND JUMP LOCATIONS WERE MATCHED WITH THE CMPUTED ONES. ENERGY LEVELS IN THE DOWNSTREAM CHANNEL PRODUCED BY THE USE OF SILLS IS COMPARED TO THE CORRESPONDING ENERGY LEVELS FOR THE CASE OF 'NO SILLS' AND THE EFFICACY OF THE USE OF SILLS IS AMPLY DEMONSTRATED. THE EXTENT OF REDUCTION OF SUPERCRITICAL STATE OF FLOW IN THE REGIONS CLOSE TO THE SILLS ACCOMPLISHED BY THE SILLS IS PRESENTED IN THE FORM OF GRAPHICAL RELATIONSHIPS BETWEEN DIFFERENT PARAMETERS PERTAINING TO THE GEOMETRY OF THE SILLS AND THE FLOW CONDITIONS. /AUTHOR/

  • Corporate Authors:

    University of Texas, Austin

    Cockrell Hall
    Austin, TX  USA  78712

    Federal Highway Administration

    1200 New Jersey Avenue, SE
    Washington, DC  USA  20590

    Texas State Department of Highways & Public Transp

    11th and Brazos Streets
    Austin, TX  USA  78701
  • Authors:
    • Rao, M V
    • Brandes, R J
    • Masch, F D
  • Publication Date: 0

Subject/Index Terms

Filing Info

  • Accession Number: 00204026
  • Record Type: Publication
  • Source Agency: Federal Highway Administration
  • Report/Paper Numbers: Study No 92
  • Files: TRIS, USDOT, STATEDOT
  • Created Date: Jan 12 1972 12:00AM