CAPWAP-Based Correlations for Estimating the Static Axial Capacity of Open-Ended Steel Pipe Piles in Alaska

CAPWAP analyses of open-ended steel pipe piles at 32 bridge sites in Alaska have been compiled with geotechnical and construction information for 12- to 48-inch diameter piles embedded in predominantly cohesionless soils to maximum depths of 161-feet. This database includes 68 piles, 33 of which tested at End of Initial Driving and Beginning of Restrike demonstrating time-effects on pile resistance. The CAPWAP analyses were used to develop empirical relationships for unit shaft and toe resistances at BOR. The CAPWAP-based unit shaft resistance demonstrates a depth-dependent trend, with values 1 to 3 days after EOID that are considerably less than estimates made using common static analyses. The toe resistance was found to be highly variable and dependent on both the prevalence of gravel and cobbles at the toe and pile diameter. Class A Prediction involving 29 piles driven into deltaic deposits demonstrated very good agreement with CAPWAP results for 1 to 6 day BOR. The proposed method provided much more reliable estimates of pile resistance than widely-adopted static analyses and modifications for set-up are proposed. The method can be refined with new data; reducing uncertainties in computed pile resistance, pile lengths, and construction costs associated with field modifications of piles.


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Filing Info

  • Accession Number: 01462599
  • Record Type: Research project
  • Source Agency: Alaska Department of Transportation and Public Facilities
  • Contract Numbers: HPR-4000(69), T2-08-01
  • Files: RiP, STATEDOT
  • Created Date: Jan 3 2013 2:06PM