Testing Protocol for Predicting Driven Pile Behavior within Pre-bored Soil

Piles at a project site derive their load carrying capacity from “side friction” along their embedded lengths as well as from “end resistance.” Pre-boring is a method used to facilitate driving of displacement piles through hard/dense soils. A pilot hole, generally smaller in size than the pile to be installed, is first bored to a specified depth. By pre-boring a pilot hole, the “end bearing” and “side friction” within the pre-bore zone are reduced, thus aiding the driving of the pile. However, pre-boring complicates the prediction of long-term pile capacity (specifically side friction) within the pre-bored zone and the Wave Equation Analysis of Pile (WEAP) analysis, which aims to predict pile drivability. The objective of this project was to compile the state-of-the-art and best practice results available on the subject of pre-bored piles and develop a research and instrumentation testing plan for future field data collection and select multiple pile driving sites representing different soil strengths. Subsurface geologic characteristics of Louisiana were used to recommend multiple pile driving sites for future testing of piles. A plan was recommended for driving multiple test piles at each site using differently sized pre-bored holes with no pre-boring as control for comparison. Instrumentation and monitoring plan utilizing vibrating wire strain gauges or embedded data collector technology during static load test as well as pile dynamic analyzer (PDA) during initial pile driving and restrikes was suggested to be included in the pile testing protocol. The field load testing and instrumentation data obtained during the proposed protocol can be used by the Louisiana Department of Transportation and Development (DOTD) and consulting engineers in evaluating the change in “side friction” capacity of piles while utilizing different size pre-bored hole. The database of information generated from the different sites will help reduce uncertainty in long term pile capacity prediction and constructability issues when using a pre-bored hole for pile installation.

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  • Summary URL:
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  • Corporate Authors:

    University of New Orleans

    Department of Civil & Environmental Engineering
    2000 Lakeshore Drive
    New Orelans, LA  United States  70148

    GeoStellar Engineering, LLC

    Baton Rouge, LA  United States 

    Louisiana Department of Transportation and Development

    1201 Capitol Access Road, P.O. Box 94245
    Baton Rouge, LA  United States  70804-9245

    Louisiana Transportation Research Center

    Baton Rouge, LA  United States 

    Federal Highway Administration

    1200 New Jersey Avenue, SE
    Washington, DC  United States  20590
  • Authors:
    • Ghose-Hajra, Malay
    • Tavera, Eduardo A
  • Publication Date: 2016-2


  • English

Media Info

  • Media Type: Digital/other
  • Edition: Final Report
  • Features: Appendices; Figures; Maps; References; Tables;
  • Pagination: 179p

Subject/Index Terms

Filing Info

  • Accession Number: 01596693
  • Record Type: Publication
  • Report/Paper Numbers: FHWA/LA.15/546, LTRC Project Number: 14-2GT, Final Report 546
  • Contract Numbers: State Project Number: 30001425
  • Created Date: Mar 29 2016 2:48PM