1. Testing of Unknown Foundation: A Case Study with Comparison of Different NDT Methods Present at Ohio Transportation Engineering Conference Oct 23-24, 2007 Bill X. Yu Assistant Professor, Department of Civil Engineering, Case Western Reserve University, OH, USA, 216-368-6247, xxy21@case.eduxxy21@case.edu

2. Acknowledgements  Jian Fang, Josh Adams, Guoming Lin, WPC, Inc., 2201 Rowland Avenue, Savannah, GA 31404, 912-629-4000  Bin Zhang, Case Western Reserve University

3. Introduction  Project Background St. Joseph hospital expansion

4. NDT Testing Plan After WPC Inc. Report, 2006

5. Impact Echo: Testing Schematic

6. Impact Echo: On-site Photos

7. Impact Echo: Examples of Analyzed Signals

8. Parallel Seismic Testing  Schematic Borehole SCPT

9. Parallel Seismic Test: Photo During Test

10. Parallel Seismic Testing: Ground Conditions by SCPT

11. Parallel Seismic Testing: Recorded Signal

12. Parallel Seismic Testing: After Signal Processing

13. Parallel Seismic Testing: Wave Train Determination

14. Parallel Seismic Testing: Wave Train

15. Parallel Seismic Testing: Wave Train Validation

16. Parallel Seismic: Sensitivity Analyses

17. Magnetometer Method: Principle

18. Magnetometer: Validation of Concept 1 ft Vertical motion

19. Magnetometer: Validation of Concept Vertical cyclic motion of rodSlow vertical motion of rod At distance of 1 ft

20. Magnetometer: Validation of Concept

22. Magnetometer Method: Recorded signal

23. Magnetometer: Signal Analyses for Pile Length

24. Design Recommendations Based on Testing Results 50 Ton

25. Advantages and Pitfalls Impact Echo Fast, easy Challenge in signal interpretation  Influence of internal reflection (due to geometry, crack etc)  Signal attenuation with depth  Wave modes Source of error: assumption of wave speed

26. Advantages and Pitfalls (cont.) Parallel Seismic Method Requires borehole Less influenced by pile integrity Requires careful signal interpretation  Wave trains  Inflection point

27. Advantages and Pitfalls (cont.) Magnetometer Method Fast, easy Requires borehole Can be influenced by soil strata

28. Summary of Experience  Geophysical methods are important tools to supplement engineering decisions  Different testing methods can serve Properly applied Properly interpreted  Geotechnical complexity needs to be considered

29. Thank you !