It has been the writer's experience in trying to establish soil set up factors using driving records and wave equation predictions that the side and point damping values of 0.20 sec/ft (0.66 sec/m) and 0.01 sec/ft (0.03 s/m), respectively, the author uses in the wave equation results in harder driving being predicted than is actually the case. A point damping value three times (rather than the author's 0.05 times) the side damping value has been recommended more often in the past. Experience indicates the 80 percent efficiency used for a Menck hammer is high, and 70 percent is a reasonable upper bound. Without the use of pile head instrumentation it is extremely difficult to establish pile efficiency based solely on observed hammer behavior. Observing the hammer stroke or counting blows per minute is not an accurate means of estimating hammer efficiency. It is felt that in set up determination the first foot of redrive should not be ignored as has been suggested. In the case of resuming after some dealy, a greater effort will be required for the first foot than the second. Changes in the ratio of skin friction to point resistance can be compensated for by adjusting the resistance ratio in the wave equation analysis.

  • Availability:
  • Supplemental Notes:
    • Discussion of Proceeding Paper 13293 by Vasant N. Nijayvergiya, Alymer P. Cheng and Henricus J. Kolk, October, 1977.
  • Corporate Authors:

    American Society of Civil Engineers

    345 East 47th Street
    New York, NY  United States  10017-2398
  • Discussers:
    • Naughton, H R
  • Publication Date: 1978-9

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Filing Info

  • Accession Number: 00183215
  • Record Type: Publication
  • Report/Paper Numbers: ASCE 13999
  • Files: TRIS
  • Created Date: Nov 14 1978 12:00AM