BRIDGE PIER SCOUR IN UNSTEADY FLOW

A laboratory investigation of scouring at a cylindrical pier during passage of a flood wave is described. Tests were done with single waves and with series of up ten successive waves under both clear water and live bed conditions. In clear water waves scour depths on the rising limb were always less than corresponding steady state scour depths. Even though scouring continued on the falling limb the steady scour depth corresponding to the peak discharge was never reached. Scour depths increased with the passage of successive waves reaching a maximum after about eight waves. This maximum was strongly dependent on the peak discharge in the wave and in these tests reached 90% of the steady scour depth corresponding to the peak discharge. Passage of waves throughout which live bed conditions occurred did not cause any change in mean scour depth. It is concluded that scour failures during floods are not due so much to flood effects (always assuming the flows have been estimated correctly) but to the lack of a reliable method for predicting steady state scour depths. (Author)

  • Corporate Authors:

    National Roads Board, New Zealand

    P.O. Box 12-041
    Wellington,   New Zealand 
  • Authors:
    • Sutherland, A J
  • Publication Date: 1979

Media Info

Subject/Index Terms

Filing Info

  • Accession Number: 00315369
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Dec 11 1980 12:00AM