FIELD STUDY OF PILE GROUP ACTION. APPENDIX A

This report is the final report for a study involving the static vertical load testing of a full scale, instrumented pile group. The test group consisted of nine pipe piles instrumented for settlement, load transfer, pore pressures, total pressures and inclination. Two similarly instrumented reference (control) piles were also installed. Two smaller subgroups within the main group were also tested, and uplift tests were conducted on several of the individual piles. The soils at the test site consisted of clays that were overconsolidated by desiccation. It was determined that the efficiency of the main group and of the subgroups was essentially unity. Settlement ratios in the working load range were found to vary from about 1.2 to about 1.7, depending on the number of piles that were loaded. Failure was observed to be by plunging of the individual piles. Unit side load transfer varied essentially linearly with depth. Some dependence of load transfer patterns on residual stresses that remained after driving the piles was observed. The measured behavior of the group and subgroups was modeled by the "hybrid" algorithm, by means of Program PILGP1, which was developed for this study and documented in Appendices A and B. Good agreement between computed and measured results were achieved when the unit load transfer curves from the reference piles were used and when the soil modulus of deformation was appropriately adjusted to account for pile reinforcement of the soil and the presence of very small strains in the mass of soil around the group. (FHWA)

  • Corporate Authors:

    Raymond International Builders, Incorporated

    2801 South Post Oak Road
    Houston, TX  United States  77027

    Federal Highway Administration

    Engineering Research and Development Bureau, 1200 New Jersey Avenue, SE
    Washington, DC  United States  20590
  • Authors:
    • Ha, H B
  • Publication Date: 1981-3

Media Info

  • Pagination: 102 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00345102
  • Record Type: Publication
  • Report/Paper Numbers: FHWA-RD-81- 3 Final Rpt., FCP 34H2-032
  • Contract Numbers: DOT-FH-11-9526
  • Files: TRIS, USDOT
  • Created Date: Jan 29 1982 12:00AM