FIELD MEASUREMENTS OF THE SETTLEMENT RATIOS OF VARIOUS HIGHWAY CULVERTS

RESEARCH WAS CONDUCTED ON THE DETERMINATION OF THE SETTLEMENT RATIOS WHICH ACTUALLY DEVELOPED DURING AND SUBSEQUENT TO THE CONSTRUCTION OF THE EMBANKMENTS OVER A HUMBER OF ACTUAL CULVERTS WHICH WERE BUILT ON THE HIGHWAY SYSTEM. THE SETTLEMENT RATIO IS NECESSARY IN THE COMPUTATION OF THE LOAD ON A CULVERT OR PROJECTING CONDUIT, WHEN LOADS DUE TO THE EMBANKMENT MATERIAL ARE TO BE DETERMINED BY MEANS OF MARSTON'S THEORY OF LOADS ON UNDERGROUND CONDUITS. MARSTON'S LOAD THEORY AND THE MATHEMATICAL DERIVATION OF THE LOAD FORMULAS ARE DESCRIBED. METHODS USED AND RESULTS OBTAINED IN TWO SERIES OF FIELD MEASUREMENTS ARE DESCRIBED, IN WHICH THE SETTLEMENT RATIOS OF 24 ACTUAL CULVERTS WERE DETERMINED. THESE CULVERTS INCLUDED BOTH RIGID AND FLEXIBLE PRE-FABRICATED PIPE STRUCTURES AND MONOLITHIC CAST-IN-PLACE BOX AND ARCH CULVERTS. ONE SERIES OF SETTLEMENT RATIO DETERMINATIONS WERE MADE BY MEASURING CULVERT LOADS WITH STAINLESS STEEL FRICTION RIBBONS WHICH WERE INSTALLED AND CALIBRATED PRIOR TO THE CONSTRUCTION OF THE FILLS. NORMAL PRESSURES WERE DETERMINED FROM WHICH THE LOADS ON THE CULVERTS WERE COMPUTED. USING THESE LOADS AND RATIOS OF HEIGHTS OF FILL TO WIDTH OF CULVERT AND THE PROJECTION RATIOS, AND ASSUMING VALUES FOR THE UNIT WEIGHT OF THE FILLS, THE PROBABLE SETTLEMENT RATIOS FOR THE CULVERTS WERE DETERMINED FROM MARSTON'S LOAD FORMULA. THE SETTLEMENT RATIOS WERE DETERMINED DIRECTLY IN A SECOND SERIES OF CULVERTS, BY MEASURING THE SETTLEMENT OF VARIOUS ELEMENTS OF THE STRUCTURES, OF THE NATURAL GROUND SURFACES AND OF THE FILLS ADJACENT TO THE STRUCTURES. THESE MEASURED SETTLEMENTS WERE SUBSTITUTED DIRECTLY IN THE FORMULA FOR SETTLEMENT RATIO AND THE VALUES FOR EACH CULVERT OBTAINED. IN THE CASE OF FIVE CORRUGATED METAL FLEXIBLE PIPE CULVERTS WHICH WERE INCLUDED IN THE STUDY, CERTAIN IMPORTANT AUXILIARY INFORMATION CONCERNING THE MODULUS OF PASSIVE PRESSURE OF THE SIDE-FILL MATERIALS AND THE DEFLECTION LIKE FACTORS FOR THE CULVERTS AS INSTALLED WERE OBTAINED. THE SETTLEMENTS OF THE SOIL ADJACENT TO THE CULVERTS AT VARIOUS PLANES WITHIN THE EMBANKMENTS WERE MEASURED WITH A DEVICE KNOWN AS THE AMES SETTLEMENT CELL. THE IMPROVED CELL DESIGN IS DESCRIBED.

  • Supplemental Notes:
    • Bulletin 170, 99 PP, 77 FIG, 6 TAB, 3 APP
  • Corporate Authors:

    Iowa State University, Ames

    Engineering Experiment Station
    Ames, IA  USA  50011
  • Authors:
    • Spangler, M G
  • Publication Date: 1950

Subject/Index Terms

Filing Info

  • Accession Number: 00216434
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Dec 9 1994 12:00AM