HYDRAULIC PERFORMANCE OF BRIDGES EXCAVATIONS AT BRIDGES

EXCAVATION INCREASES THE HYDRAULIC CAPACITY OF BRIDGES WHERE THE MINIMUM FLOW AREA OCCURS UNDER THE BRIDGE. EXCAVATION UNDER BRIDGES AS A MEANS OF INCREASING THE HYDRAULIC CAPACITY WAS STUDIED BY OBSERVING THE FALL AND DISCHARGE THROUGH FIVE BRIDGE OPENINGS ACROSS A SINGLE FLOOD PLAIN. THREE OF THE BRIDGES HAD TOTAL GET-A-WAY AREAS LARGER THAN THE AREAS UNDER THE BRIDGES BEFORE EXCAVATION AND INCREASES IN HYDRAULIC CAPACITY WERE INDICATED. A FOURTH BRIDGE HAD A GET-A-WAY SUB-AREA LARGER THAN THE EXCAVATED AREAS NEAR THE ABUTMENTS AND AN INCREASE IN HYDRAULIC CAPACITY WAS ALSO INDICATED. ONE BRIDGE HAD A RESTRICTED AREA JUST DOWNSTREAM WHICH ACTED AS THE CONTROL AREA AND NO INCREASE IN HYDRAULIC CAPACITY WAS INDICATED. DATA FROM ONE BRIDGE INDICATED THAT THE MAXIMUM EFFECTIVE AREA IS EQUAL TO THE MINIMUM AREA MEASURED ALONG THE UPSTREAM OR DOWNSTREAM PERIMETER OF THE EXCAVATION. AFTER EXCAVATION, VELOCITIES WERE LESS UNIFORM AND WERE GREATER NEAR THE BOTTOM THAN AT THE SURFACE. THE USABLE DATA IN THIS REPORT ARE LIMITED TO A SINGLE EXCAVATION FOR EACH BRIDGE. THEREFORE, OPTIMUM EXCAVATION GEOMETRY FOR BRIDGES WILL REQUIRE FURTHER STUDY. /AUTHOR/

  • Supplemental Notes:
    • MSHD-RD-73-015-EB
  • Corporate Authors:

    Mississippi State Highway Department

    P.O. Box 1850
    Jackson, MI  United States  39215
  • Authors:
    • Colson, B E
    • Wilson, K V
  • Publication Date: 1973-9

Media Info

  • Features: Figures; References;
  • Pagination: 37 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00204561
  • Record Type: Publication
  • Files: TRIS, STATEDOT
  • Created Date: Jul 31 1974 12:00AM