MODEL STUDIES OF SCOUR AROUND BRIDGE PIERS AND ABUTMENTS-SECOND PROGRESS REPORT

THE IOWA INSTITUTE OF HYDRAULIC RESEARCH IS ENGAGED IN A LABORATORY INVESTIGATION OF FOUR PHASES OF SCOUR AT BRIDGES: (1) GEOMETRY OF PIERS AND ABUTMENTS, (2) HYDRAULIC CHARACTERISTICS, (3) SEDIMENT CHARACTERISTICS, AND (4) GEOMETRY OF CHANNEL CROSS-SECTION AND ALIGNMENT. STUDY OF PHASE 2 INDICATES EQUILIBRIUM DEPTH OF SCOUR IS PRIMARILY DEPENDENT ON THE DEPTH OF FLOW AND THAT VELOCITY HAS LITTLE INFLUENCE ON EQUILIBRIUM CONDITIONS. THE INSTANTANEOUS RATE OF SCOUR, HOWEVER, IS GREATLY INFLUENCED BY THE VELOCITY, AND SCOUR DEPTHS IN EXCESS OF THE EQUILIBRIUM CONDITION CAN BE ATTAINED UNDER UNSTEADY FLOW CONDITIONS. A FLOOD, OF COURSE, IS A STATE OF UNSTEADY FLOW, AND AN ALLUVIAL STREAM WILL HAVE A TENDENCY TO DEGRADE DURING THE RISING STAGE. THE LOWERING OF THE BED RESULTS IN A VARIABLE LEVEL TO WHICH THE SCOUR DEPTH, AS DETERMINED BY THESE LABORATORY TESTS, MUST BE REFERRED. FURTHER INVESTIGATION IS NECESSARY HOWEVER, TO DETERMINE WHETHER THE EXCESS DEPTH OR THE EQUILIBRIUM DEPTH OF SCOUR WILL OBTAIN DURING THE SLOWLY VARIED FLOW OF FLOODS. /AUTHOR/

  • Supplemental Notes:
    • Vol 31, pp 82-87, 4 FIG, 2 TAB, 1 PHOT
  • Authors:
    • Laursen, E M
    • Toch, A
  • Publication Date: 1952

Media Info

  • Monograph Title: Proceedings of the Thirty-First Annual Meeting of the Highway Research Board, Washington, D.C., January 15-18, 1952
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00204364
  • Record Type: Publication
  • Files: TRIS, TRB
  • Created Date: Aug 1 1971 12:00AM