Details:

Creators:
McVay, Michael C. ; Wasman, Scott J.
McVay, Michael C. ; Wasman, Scott J. Less -
Corporate Creators:
University of Florida. Dept. of Civil and Coastal Engineering
Corporate Contributors:
United States. Dept. of Transportation
Subject/TRT Terms:
[+]
Bridge Foundations Data Collection Design Load Instrumentation Load Tests Piles (Supports) Skin Resistance Static Tests
Publication/ Report Number:
BDV31-977-13
Resource Type:
Tech Report
Geographical Coverage:
Florida
Corporate Publisher:
Florida. Dept. of Transportation
Abstract:
A total of 16 static load test results was collected in Florida and Louisiana. New static load tests on five test piles

in Florida (four of which were voided) were monitored with Embedded Data Collector (EDC) instrumentation and

contributed to the total of 16. For the voided test piles, EDC instrumentation was placed in the piles at different locations

relative to the void to compare the estimated resistances. In the four test piles, the measured top compressive stresses

measured in the solid section of the pile were typically about 25% smaller than the measured values in the voided section of

the pile. However, when the top stresses were adjusted by area (i.e., divide by 645 in2

/ 900 in2

= 0.72), then the stresses

were very comparable. Two methods were used to estimate the pile capacities: The UF method and the Tran et al. methods.

The UF method (employed in SmartPile Review) uses the Case capacity equation with variable case damping, Jc, to assess

total capacity and the Unloading Point Method for tip resistance, (i.e., skin friction = total – tip resistance). The Tran et al.

method computes side friction using a segmental approach and tip resistance using conservation of force and energy. The

Tran et al. method for side friction showed a smaller difference (6%) in predicted capacities between top solid and voided

gauge sets than the UF method (23%) using the Case Equation for the four voided test piles.

Load and Resistance Factor Design (LRFD) resistance factors () for piles with EDC were calculated for a

reliability, , of 2.33 using the First Order Second Moment (FOSM) method and the First Order Reliability Method

(FORM). For the UF method, a total of 42 pairs (measured vs. predicted; bias,  = 0.998, standard deviation,  = 0.212, and

CV = 0.212) were analyzed for the cases of EDC in both the solid and voided sections (four new test piles supported in

present project)). The FORM = 0.75 and FOSM = 0.64. A smaller data set of 34 pairs (measured vs. predicted; bias,  =

0.918, standard deviation,  = 0.172, and CV = 0.188) were analyzed for the cases of EDC only in the solid sections. The

FORM = 0.73 and FOSM = 0.62. For the Tran et al. method, a total of 39 pairs (measured vs. predicted; bias,  = 0.991,

standard deviation,  = 0.169, and CV = 0.17) were analyzed for the cases of EDC in both the solid and voided sections.

The FORM = 0.81 and FOSM = 0.68. A smaller data set of 33 pairs (measured vs. predicted; bias,  = 0.979, standard

deviation,  = 0.182, and CV = 0.186) were analyzed for the cases of EDC only in the solid sections. The FORM = 0.78 and

FOSM = 0.66. For the Fixed Jc method, FORM and FOSM were calculated for limited data sets (solid/voided and only solid

sections). The listed resistance factors should be used with caution due to the limited data set and the conditions they were

obtained (e.g., limited soil types tested, time between BOR and static load test, lack of fully instrumented tests piles).


Format:
PDF
Collection(s):
US Transportation Collection
Main Document Checksum:
[+]
urn:sha256:6f007fac5c21ca2e43e7430de419d6a5e1d39d1a951ebf0b3f68497875cde444
Download URL:
https://rosap.ntl.bts.gov/view/dot/29547/dot_29547_DS1.pdf
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