DAMPING OF STRESS WAVES IN PILES DURING DRIVING. RESULTS FROM FIELD TEST.

THE DECREASE IN THE AMPLITUDE OF THE STRESS WAVE AS IT TRAVELS DOWN A PILE DURING DRIVING WAS INVESTIGATED. THE DAMPING WAS MEASURED BY STRAIN GAUGES ATTACHED TO THE INSIDE SURFACE OF FOUR STEEL PIPE PILES HAVING AN 89 MM OUTSIDE DIAMETER. ONE OF THE PILES WAS TESTED UNSUPPORTED IN AN OPEN SHAFT IN ORDER TO INVESTIGATE THE DAMPING IN THE PILE MATERIAL AND IN THE WELDED JOINTS. TWO PILES, ONE WITH A ROUGH SURFACE AND ONE WITH A SMOOTH SURFACE WERE DRIVEN THROUGH SAND. THE FOURTH PILE WHICH HAD A SMOOTH SURFACE WAS DRIVEN THROUGH SOFT CLAY. MEASUREMENTS SHOW THAT THE DAMPING IN THE STEEL MATERIAL AND IN THE WELDED JOINTS IS SMALL AND NEGLIGIBLE COMPARED TO THE DAMPING CAUSED BY FRICTION OR ADHESION ALONG THE PILE SURFACE. THE DAMPING IN THE PILES WITH A SMOOTH SURFACE WAS FOUND TO BE ABOUT THE SAME FOR SAND AS FOR CLAY. THE AMPLITUDE DECREASED BY ABOUT 1% PER METRE LENGTH OF PILE WHILE THE DAMPING FOR THE PILE WITH THE ROUGH SURFACE WHICH WAS DRIVEN THROUGH SAND WAS 2 TO 3% PER METRE. THE OBSERVED DAMPING WAS FOUND TO BE PROPORTIONAL TO THE PARTICLE VELOCITY IN THE PILE. ON THE BASIS OF THIS OBSERVATION AN EQUATION WAS DERIVED, WHICH RELATES THE DAMPING TO THE PILE MATERIAL, THE PILE DIAMETER, THE CROSS SECTIONAL AREA AND THE PILE LENGTH.

  • Corporate Authors:

    Saertryck & Preliminaera Rapporter

    Banergaton 16
    Stockholm S-11526,   Sweden 
  • Authors:
    • Fjelkner, G
    • Broms, B
  • Publication Date: 1972

Media Info

  • Features: Figures; Photos; References; Tables;
  • Pagination: 43 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00081078
  • Record Type: Publication
  • Source Agency: Transport and Road Research Laboratory (TRRL)
  • Report/Paper Numbers: No. 50 Intrm Rpt.
  • Files: ITRD, TRIS
  • Created Date: Apr 8 1975 12:00AM