LOAD STUDIES ON DRILLED SHAFTS

THE CAST-IN-PLACE CONCRETE PILE IS FREQUENTLY THE MOST ECONOMICAL TYPE SUBSTRUCTURE FOR BRIDGES AND BUILDINGS. HOWEVER, THERE IS A CERTAIN AMOUNT OF DISAGREEMENT AMONG ENGINEERS CONCERNING THE PROPER DESIGN OF THESE PILES, ESPECIALLY IN EVALUATING THE RELATIVE IMPORTANCE OF SKIN FRICTION AND BEARING FROM THE STANDPOINT OF LOAD SUPPORTING CAPACITY. TWO SERIES OF FIELD TESTS HAVE BEEN COMPLETED. IN THE FIRST GROUP OF TESTS THE PILE DIAMETER WAS KEPT CONSTANT AND THE EFFECTIVE LENGTH VARIED FROM 6 TO 18 FEET. IN THE SECOND SERIES, THE EFFECTIVE LENGTH WAS KEPT CONSTANT AND THE PILE DIAMETERS VARIED FROM 13 TO 24 INCHES. THE TEST PROCEDURE AND THE RESULTS OF THESE FIELD LOAD TESTS ARE DISCUSSED. A SPECIAL PRESSURE CELL (BASED ON ELECTRICAL RESISTANCE GAGES) WAS DEVELOPED TO MEASURE BEARING AT THE BASE OF THE PILE. THIS TYPE PRESSURE DEVICE WAS SUCCESSFULLY INSTALLED AT THE BASE OF SEVERAL PILES. READINGS OF THE CELL DURING THE LOAD TEST INDICATED ONLY A SMALL PART OF THE TOTAL LOAD TO BE CARRIED AS BEARING. THIS WAS ALSO INDICATED TO BE THE SITUATION FOR SPECIAL TESTS CONDUCTED ON A "GREASED PILE" (REPRESENTING A CONDITION OF NO SKIN FRICTION) AND A "FALSE BOTTOM" PILE WHICH GAVE A CONDITION OF NO BEARING. /AUTHOR/

  • Supplemental Notes:
    • Vol 34, pp 152-162, 15 FIG, 7 REF
  • Authors:
    • Dubose, L A
  • Publication Date: 1955

Media Info

  • Monograph Title: Proceedings of the Thirty-Fourth Annual Meeting of the Highway Research Board, Washington, D.C., January 11-14, 1955
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00209464
  • Record Type: Publication
  • Files: TRIS, TRB
  • Created Date: Jun 5 1972 12:00AM