1. AFT STATNAMIC Load Testing of High Capacity Marine Foundations
By: Mike Muchard, P.E.
Applied Foundation Testing, Inc.

2. Outline St. George Island Project Description
Instrumentation of Cylinder Piles
STATNAMIC, Static and Dynamic Testing
Class A Comparison of Test Methods

3. St. George Island Bridge
Boh Bros. Construction Co. Inc,
Sverdrup Civil, Inc.
4.1 Miles
54” Cylinder Piles
750 to 900 Ton Factored Design Loads.
Weathered Limestone Bearing Material

4. St. George Island Bridge Load Test Program
6 Non-Production Test Piles
All Test Piles Instrumented with multiple levels of Strain Gages
6 STATNAMIC Tests
4 Static Tests
Dynamic Testing on Test Piles and 50 Production Piles
Static and Dynamic Tests Performed by Geo Consultant

5. Pile Instrumentation

6. Post Tensioning Strains

7. Post Tensioning Stress

8. Post Tension Measurements 54” Cyclinder Pile
Eccentricity
Non-Uniform Contact Between Segements
Arching
760 to 1,010 psi Pre-stress
Composite Modulus of Elasticity 5,725 ksi
Back Calculated f’c over 10,000 psi

9. Pile Driving and Dynamic Testing (PDA)

10. Soil and Foundation Conditions

11. Driving Measurements

12. Measurements During Driving
Stresswave Propagation.
Maximum Tension Occurs Near Pile Top.
Toe Remains In Compression.
Resistance Not Mobilized Simultaneous. Therefore, Modeling Required for Distribution.

13. 1,600 Ton Static Load Testing

14. 2,000 Ton STATNAMIC Device

15. Statnamic Test Description

16. Stages of a STATNAMIC Test
Before Test
The Test
After Test
Load Produced F = ma

17. Instrumentation

18. Load Cell Calibrated Full Scale
Laser Projector & Capacitive Accelerometers

19. Data Acquisition

20. STATNAMIC Analysis

21. STATNAMIC Load Distribution

22. Three Loading Characteristics

23. STATNAMIC Has Similarities to Each Test Method
Load Duration Precludes Stresswaves
Pile displaces as a unit (like a static test)
Much Simpler Analysis
Not an Impact
Rapid Translation, Inertia and Damping must be Subtracted
Rate of Loading Must Also be Considered Via Rate Factor (Mullins, NCHRP, 2005)

24. Test Pile 1 - Composite

25. Test Pile 2 - Composite

26. Test Pile 3 - Composite

27. Test Pile 5 - Composite

28. Pile No. CAPWAP Total (kips) Static STATNAMIC LT-1 1950 2136 2166 LT-2
2016
3109
3052
LT-3
1820
3060
3113
LT-5
2028
2889
2631
CAPWAP – 14 day Re-strike
STATNAMIC performed 2 days After Static Test LT-5

29. CAPWAP / Static

30. STATNAMIC / Static

31. Friction Comparison

32. End Bearing Comparison

33. Conclusions Class A Test Method Comparison.
Instrumentation Allowed Measurement of Pre-stress, and Load Distribution During Testing.
Dynamic Testing Under-predicted Capacity 9% to 41%.
CAPWAP Skin Friction and End Bearing Predictions had Large Disagreement.
STATNAMIC within 2% of Static Capacity on Three Piles and 9% Below in the Fourth Pile.

34. Thank You
Any Questions?
AFT
Applied Foundation Testing, Inc.