DISCUSSION OF PILE-DRIVING FORMULAS FOR FRICTION PILES IN SAND

DISCUSSION BY EDWARD K. ANDERSON IS INTENDED TO LEND SUPPORT TO THIS PAPER BY SUPPLYING ADDITIONAL DATA THAT MAY BE OF INTEREST TO THE AUTHORS AND READERS. THE RESULTS OF 315 TESTS OF STEEL H, STEEL PIPE, STEEL MONOTUBE, STEP TAPERED, TIMBER, CONCRETE, AND CONCRETE PIPE PILES ARE SHOWN GRAPHICALLY IN 7 FIGURES PRESENTED. THESE DIAGRAMS ARE OF THE MEASURED PILE TEST LOAD THAT PRODUCED A 0.25-IN. GROSS SETTLEMENT OF THE PILE HEAD VERSUS THE INDICATED DYNAMIC CAPACITY OF THE PILE AS OBTAINED FORM THE PACIFIC COAST FORMULA. THE VALUES OF THE FORMULA ARE IDENTICAL TO THOSE DESCRIBED IN THE PAPER EXCEPT FOR THE VALUE OF S, WHICH IS OBTAINED FROM THE NUMBER OF BLOWS FOR THE LAST FOOT OF PILE DRIVEN. THE USE OF THE PACIFIC COAST FORMULA DOES NOT IMPLY THAT THE WRITER ADVOCATES ITS USE. IT IS RECOMMENDED THAT AN ENGINEER SHOULD NOT BE SATISFIED WITH THE USE OF ANY PILE- DRIVING FORMULA WITHOUT FIRST OBTAINING AN INDIVIDUAL PILE A-VALUE BY WHICH THE REMAINING PILES IN THE PROJECT CAN BE RELATED TO THE LOAD TEST. THE WRITER REITERATES THE OFTEN STATED FACT THAT PILE-DRIVING FORMULAS SHOULD ONLY BE USED AS A YARDSTICK BY WHICH THE UNIFORMITY OF THE FOUNDATION IS MEASURED AND OBSERVED. MR. CAMERON SUGGESTS THAT THE AUTHORS' CONCLUSIONS AS TO THE ACCURACY OF THE VARIOUS FORMULAS REQUIRES QUALIFICATION. NO ONE WILL ARGUE WITH THEIR CONCLUSIONS REGARDING THE UNSUITABILITY OF THE ENGINEERING NEWS FORMULA. THE AUTHORS RECOMMEND THE USE OF THE ADJUSTED GATES FORMULA. THE GATES FORMULA CERTAINLY FITS THE RESULTS STUDIED. HOWEVER, A STUDY OF THE FORM OF THE GATES FORMULA WILL SHOW THAT THIS AGREEMENT MUST BE FORTUITOUS. ONLY THE SAME THREE VARIABLES ENTER INTO THE FORMULA THAT APPEAR IN THE ENGINEERING NEWS FORMULA. THE FORMULA, THEREFORE, IGNORES THE FOLLOWING FACTORS: (1) RELATIVE WEIGHT OF PILE AND RAM, (2) MATERIAL AND CROSS- SECTIONAL AREA OF PILE AND, THEREFORE, THE ELASTIC LOSSES IN THE PILE, (3) THE MATERIAL AND THICKNESS OF THE PILE DRIVING CAP AND, THERFORE, THE ELASTIC LOSSES IN THE CAP, AND (4) THE NATURE OF THE GROUND INTO WHICH THE PILE IS DRIVEN AND, THEREFORE, THE LOSSES ASSOCIATED WITH TEMPORARY COMPRESSION OF THE GROUND. THE ONLY ONE OF THE SEVEN FORMULAS WHICH INCLUDES FACTORS FOR ALL VARIABLES LISTED IS THE HILEY FORMULA. REFERENCES: PILE DRIVING FORMULAS FOR FRICTION PILES IN SAND, R.E. OLSON AND K.S. FLAATE, ASCE (PROC. PAPER 5604), NOVEMBER 1967.

  • Supplemental Notes:
    • Vol 95, No SMI, PP 375-378, 7 FIG
  • Corporate Authors:

    N/A

    ,   United States 
  • Authors:
    • Anderson, E K
    • Cameron, I G
  • Publication Date: 0

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  • Accession Number: 00232676
  • Record Type: Publication
  • Report/Paper Numbers: No SM5, Proc Paper 490
  • Files: TRIS
  • Created Date: Aug 15 2004 2:44AM