ANALYSIS OF LOADS AND SUPPORTING STRENGTHS AND PRINCIPLES OF DESIGN FOR HIGHWAY CULVERTS

THE PRINCIPLES OF THE MARSTON THEORY OF LOADS ON UNDERGROUND CONDUITS WHICH ARE APPLICABLE TO THE DESIGN OF HIGHWAY CULVERTS ARE PRESENTED. WHEN ANALYZING THE LOADS ON UNDERGROUND CONDUITS WHICH ARE CAUSED BY THE OVERLYING FILL, THEY MAY BE CONVENIENTLY GROUPED INTO TWO MAIN CLASSES, VIZ., DITCH CONDUITS AND PROJECTING CONDUITS. THESE CLASSES ARE DEFINED AND ILLUSTRATED AND APPROPRIATE FORMULAS ARE PRESENTED FOR COMPUTING THE LOADS ON EACH CLASS. IT IS POINTED OUT THAT THE LOADS DUE TO EARTH FILLS ARE DEPENDENT UPON A NUMBER OF FACTORS, SUCH AS THE WIDTH OF DITCH, THE PROJECTION RATIO, THE SETTLEMENT RATIO, THE WIDTH OF THE CONDUIT AND THE HEIGHT OF FILL. ALSO, THE AFFECT ON LOAD OF PROPERTIES OF THE OVERLYING SOIL SUCH AS ITS UNIT WEIGHT AND COEFFICIENT OF INTERNAL FRICTION IS DISCUSSED AND THE PRINCIPLES GOVERNING THE TRANSMISSION OF LIVE LOADS THROUGH SHALLOW SOIL COVERING ARE PRESENTED. A NUMBER OF SPECIAL CASES OF CULVERT CONSTRUCTION ARE DESCRIBED, SEVERAL OF WHICH MAY BE RELIED UPON TO PROTECT THE CONDUIT FROM EXCESSIVELY HIGH LOADS IN THE CASE OF UNUSUALLY HIGH FILLS OVER THE STRUCTURE. THE METHODS ARE DISCUSSED OF TESTING RIGID CIRCULAR PIPES, BEDDING THE PIPES IN FIELD INSTALLATIONS AND DETERMINING THE SUPPORTING STRENGTH OF THIS TYPE OF CONDUIT WHEN LAID IN VARIOUS CLASSES OF BEDDING CONDITIONS. IN THE CASE OF RIGID PROJECTING CONDUITS, THE FIELD SUPPORTING STRENGTH IS INFLUENCED TO A CONSIDERABLE EXTENT BY THE ACTIVE LATERAL PRESSURE OF THE SOIL FILL MATERIAL WHICH ACTS AGAINST THE SIDES OF THE PIPE AND HELPS TO SUPPORT THE VERTICAL LOAD. THIS FACT IS TAKEN INTO ACCOUNT IN EVALUATING THE SUPPORTING STRENGTH OF THIS CLASS. ALSO, SOME PRINCIPLES GOVERNING THE CHOICE OF A SUITABLE FACTOR OF SAFETY FOR RIGID TYPES OF CONDUITS ARE DISCUSSED BRIEFLY. THE SUPPORTING STRENGTH OF FLEXIBLE STRUCTURES SUCH AS CORRUGATED METAL PIPE CULVERTS IS EVALUATED ON THE BASIS OF THE DEFLECTION OF THE FLEXIBLE PIPE UNDER THE INFLUENCE OF THE VERTICAL LOAD AND OF THE PASSIVE RESISTANCE PRESSURE OF THE FILL MATERIAL AT THE SIDES OF THE PIPE DURING THEIR OUTWARD MOVEMENT AGAINST THE SOIL AS DEFLECTION PROGRESSES. A FORMULA FOR ESTIMATING THE ULTIMATE DEFLECTION OF A FLEXIBLE PIPE CULVERT IS GIVEN, FOR PIPES WHICH ARE INSTALLED WITHOUT STRUTS OR OTHER PRE-STRESSING DEVICES /AUTHOR/

  • Supplemental Notes:
    • Vol 26, pp 189-214, 14 FIG, 4 TAB, 16 REF
  • Authors:
    • Spangler, M G
    • Barber, E S
  • Publication Date: 1947

Media Info

  • Monograph Title: Proceedings of the Twenty-Sixth Annual Meeting of the Highway Research Board Held at Washington, D.C. December 5-8, 1946
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00216433
  • Record Type: Publication
  • Files: TRIS, TRB
  • Created Date: Dec 9 1994 12:00AM