This discussion points out some of the drawbacks of the expandable tip piling. The technique is restricted to steel piles. Even if the concrete pile has to be used at the places where the steel plates are to be extruded, the steel pile will be connected to the concrete file. Although the technique looks sound and economical, it has many inherent defects. During the driving of the expandable tip piling, the steel plates may be dislocated. In large piles, the length of the taper plunger or taper screw to extrude the steel plates becomes abnormally long and this makes it necessary to situate the lowest steel plates quite a distance from the tip. Though this does not affect the bearing capacity, it reduces the capacity in tension. The discussants express the opinion that the adhesion factor in bearing will be more than in tension, since during compressive loading the length of the pile embedment goes on increasing, while during tension the opposite is true. It is also noted that the authors have neglected the overburden pressure in their theoreical calcualtions in the model tests. This may cause significant error in the prototype. In tension model tests, the difference between theoretical results and tests results are not appreciable, except for the three-ring model. Observations are also made with regard to the authors test results on the reduced scale prototype. The authors' in their design example have indicated that there is a 33 percent saving in the number of piles but the discussants state that in practice the percentage saving may be 12-19 percent.

  • Availability:
  • Supplemental Notes:
    • Discussion of Proc. Paper 10161 by Thomas I. Admas and Fred C. Stepanich, published in November 1973.
  • Corporate Authors:

    American Society of Civil Engineers

    345 East 47th Street
    New York, NY  United States  10017-2398
  • Discussers:
    • Ramiah, B K
    • Raghunath, S P
  • Publication Date: 1974-8

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Filing Info

  • Accession Number: 00261628
  • Record Type: Publication
  • Report/Paper Numbers: Proc Paper 10695
  • Files: TRIS
  • Created Date: Nov 6 1974 12:00AM