DISCUSSION OF THEORETICAL BEARING CAPACITY OF VERY SHALLOW FOOTINGS

THE REASON WAS INVESTIGATED FOR THE DISCREPANCY IN THE BEARING CAPACITY RESULTS OBTAINED BY THE AUTHOR AND IN OTHER STUDIES. THE AUTHOR TAKES THE SHEAR STRENGTH OF THE SOIL ABOVE FOUNDATION LEVEL INTO ACCOUNT, BUT ACCORDING TO A PRESENTED FIGURE, THE RANKINE ZONE IS SIMPLY EXTENDED ABOVE THIS LEVEL, AND IT IS ALSO IMPLIED THAT A PASSIVE EARTH PRESSURE CORRESPONDING TO A PERFECTLY SMOOTH WALL IS ACTING ON EACH OF THE TWO VERTICAL FACES AB OF THE FOOTING. THIS PROBLEM IS UNDER STUDY AT THE DANISH GEOTECHNICAL INSTITUTE. THE THEORETICAL CALCULATION OF BEARING CAPACITIES FOR CIRCULAR FOOTINGS ARE OPEN TO DOUBT ON TWO POINTS WHICH ARE DISCUSSED. THE HAAR AND VON KARMAN HYPOTHESIS IS INCOMPATIBLE WITH THE PROPORTIONALITY BETWEEN THE PLASTIC STRAIN AND THE DEVIATOR STRESS TENSORS POSTULATED BY REUSS, AND THE USE OF THE HAAR AND VON KARMAN HYPOTHESIS IMPLIES THAT THE FRICTION ANGLES FOR WHICH THE AVERAGE BEARING PRESSURES ARE CALCULATED ARE THOSE CORRESPONDING TO A TRIAXIAL STATE OF STRAIN. MR. KARAFIATH COMMENDS THE NUMERICAL METHOD USED BY THE AUTHOR TO INVESTIGATE THE THEORETICAL BEARING CAPACITY OF SHALLOW FOOTINGS. IT IS RECOMMENDED THAT THE COMPUTER PROGRAM BE ADAPTED TO VARIOUS BOUNDARY CONDITIONS, AS THE AUTHOR ADAPTED THE METHOD TO INCLUDE THE SOIL ABOVE THE BASE OF THE FOOTING IN THE SLIP LINE FIELD RATHER THAN CONSIDERING IT AS A SURCHARGE. THE WRITER AGREES WITH THE AUTHOR THAT OTHER FACTORS, SUCH AS ROUGHNESS OF THE FOOTING, ALSO HAVE SIGNIFICANT INFLUENCES ON BEARING CAPACITY. THIS EFFECT MAY BE EASILY INVESTIGATED BY THE NUMERICAL METHOD. REFERENCES: THEORETICAL BEARING CAPACITY OF VERY SHALLOW FOOTINGS, LAWRENCE A. LARKIN, ASCE PROCEEDINGS PAPER 6258, NOVEMBER, 1968.

  • Supplemental Notes:
    • Vol 95, No SM6, PP 1568-1573, 4 FIG
  • Authors:
    • Hansen, B
    • Christensen, N H
    • Karafiath, L L
  • Publication Date: 1969-11

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Filing Info

  • Accession Number: 00235592
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Feb 9 1970 12:00AM