Field instrumentation and testing to study set-up phenomenon of piles driven into Louisiana clayey soils : final report.

Details

• Creators:
  Abu-Farsakh, Murad Y. ; Haque, Nafiul ; Chen, Qiming
• Corporate Creators:
  Louisiana State University. Department of Civil and Environmental Engineering
• Corporate Contributors:
  Louisiana. Dept. of Transportation and Development ; United States. Federal Highway Administration
• Subject/TRT Terms:
  • Clay soils
  • Field tests
  • Instrumentation
  • Load tests
  • Pile driving
  • Pile foundations
  • Resistance (Mechanics)
  • Soil mechanics
  • Load and resistance factor design
• Publication/ Report Number:
  FHWA/LA.15/562
• Resource Type:
  Tech Report
• Geographical Coverage:
  United States ; Louisiana
• Edition:
  Final report
• Corporate Publisher:
  Louisiana Transportation Research Center
• Abstract:
  This research study aims to investigate the pile set-up phenomenon for clayey soils and develop empirical models to predict pile set-up ; resistance at certain time after end of driving (EOD). To fulfill the objective, a total number of twelve prestressed concrete (PSC) test ; piles were driven in different soil conditions of Louisiana. Detailed laboratory and in-situ soil testing were performed at each test pile ; location in order to characterize the subsurface soil condition. Dynamic load tests and static load tests were performed at different times ; after EOD to verify the axial resistances of piles and to quantify the amount of increase in resistance (i.e., set-up) compared to the EOD. ; The focus of this research was to calculate the resistance of individual soil layers with time along the length of the pile. In order to ; implement this goal, all the test piles were instrumented with vibrating wire strain gages. The measurements of vibrating wire strain gages ; were used to measure the distribution of load transfer along the length of the pile during the static load tests. Vibrating wire piezometers ; and pressure cells were also installed in the pile face in order to calculate the time for dissipation of excess pore water pressure and ; corresponding increase in effective stress with time. Case Pile Wave Analysis Program (CAPWAP) was performed in all the dynamic ; load test data and used to calculate the side resistance of individual soil layers along the length of the pile during dynamic load tests. ; Logarithmic set-up parameter “A” of individual soil layers were calculated using the unit side resistance. The set-up parameter “A” was ; correlated with different soil properties such as undrained shear strength, plasticity index, coefficient of consolidation, sensitivity and ; overconsolidation ratio (OCR). Three different levels of empirical models were developed to estimate the magnitude of pile set-up with ; time. The developed models were used to predict the total resistance of piles in the database at four different time intervals (i.e., 30 days, ; 45 days, 60 days and 90 days) after EOD. Reliability analyses were performed to calibrate the set-up resistance factor (ϕset-up) for ; incorporating it into the LRFD pile design methodology. Accordingly, a set-up resistance factor (ϕset-up) of 0.35 is recommended. A ; framework for estimating the duration of pile set-up based on consolidation theory of soils at the pile face was introduced.
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• Format:
  PDF
• Funding:
  LTRC Number: 11-2GT State Project No. 736-99-1732
• Download URL:
  https://rosap.ntl.bts.gov/view/dot/31026/dot_31026_DS1.pdf
• File Type:
  [PDF - 6.19 MB]
• Collection(s):
  US Transportation Collection
• Main Document Checksum:
  urn:sha256:ec5694ffbf08fae804705ce976cb08dfc66da60aefd7ed00916febc54d662ff7