1. Classical and Finite Difference Method to Estimate pile Capacity Compared With Pile Load Test Results Yogesh Prashar, P.E., GE Force Pulse Conference, DFI January 2012 Oakley, California www.m2consultantsinc.com

2. Presentation Outline Description & Background Pile Load Testing & Results ETC –3 Conventional Uplift Tests –12 RLT Compression Theoretical Load Settlement Calculations FLAC Simulation of Uplift & RLT Comparisons & Rapid Loading BART, UCSF, & N4 West Conclusions

3. Site MapSite Air Photo Emeryville, N. California

4. 900’ 400’ 15-test Pile Locations 12 RLT 3 Uplift - Pile Load Test 16-in Square pre-cast concrete piles RLT Conventional Uplift Test

5. Site Plan & Boring Locations Cross Section Line A-A’ & B-B’ 12 Borings & 7 CPT’s Laboratory Testing A’ N TEST AREA Site Plan & X-Section Line

6. 900-ft Soil Profile

7. CU Triaxial Testing

8. Emeryville Soil Profile *=Friction angle and Cohesion parameters were increased 25 & 50% in parametric analysis Fill: (pre-drilled) Soft - Silty Clay Firm Sandy Clay Stiff Sandy Clay V. Stiff Sandy Clay 10’ 35’ 10’ 18’ 115 20 0 NA 110 5 200 0.9 125 20/24.5/28.6* 400/500/600* 0.9 130 24/27.9/32.5* 600/750/900* 0.8 130 27/32.5/37.4* 1000/1250/1500* 0.75 No. 16” Square Pile Soil Type  (pcf)  (deg) C (psf) Ca/C 1234512345 86’

9. 0.0 2.0 4.0 6.0 8.0 10.0 12.0 14.0 25.0 35.0 45.0 55.0 65.0 75.0 85.0 95.0 PILE LENGTH (ft) PILE DRIVING (BLOWS PER FOOT ) IP7 IP8 IP9 IP10 IP5 IP11 IP12 IP13 Pile Driving Blow Counts & N-Values

10. ASTM D 1143 Static Pile Load Test Three piles were tested Load applied with hydraulic jacks Deflection by Dial indicators Plotted Measured Load versus deflection Material Parameters were back calculated to fit Conventional load deflection curves Parameters fit within a range of field and lab tests results

11. ASTM D 1143 Test Frame Test Pile Reinforcing Bars Wooden Planks Subsurface Soils Dial Indicators (deformation) Load Cell (Load) Ca

12. RLT Procedure 25,000 kg mass dropped on pile from varying heights Deflection Measured @ Point of Impact Force applied to pile top for 200-ms duration Energy transmitted to pile via anvil and dampened via springs Springs recoil and push load up to unload pile

13. FUNDEX-PLT BLACK BOX TEST SETUP RLT Equipment

14. Hydraulic Clamp 25,000 kg mass Damping Springs Test Pile Anvil Subsurface Soils Black Box Data Rec. RLT Procedure

15. RLT Load Application

16. Rate of Loading Ladd 1974 & Graham 1983 S u /(S u for  =1%/hr)=1.0+0.1*Log s Where: S u = Undrained shear strength s= Strain The resulting loading rate for the RLT is: 3.6X10 6 Percent/Hour. Therefore SI for Cohesive soils is 1.7

17. Davisson Method - Pile Capacities Plot Load versus Deflection Plot pile elastic shortening line Compute offsett  =0.15+0.1(B/12) Plot line parallel to elastic shortening line Compute pile capacity form curve

18. Theoretical Pile Capacities NAVFAC 7.2 Input parameters: –K hc =1.5 K ht =0.75  =0.75 –E p,=4.415E6-psiC p,=0.03  s =0.33 Total Elongation:  t =  p +  fric. Total Settlement:  t =  p +  fric. +  tip

19. Uplift Test Analysis & Results

20. Summary of Results

21. RLT & Theory

22. Numerical Modeling - FLAC FLAC – 2D Finite Difference Model Cohesion parameter from CU Triaxial Mohr Coulomb Model Pile Element to model 16-inch square pile Soil pile interaction parameters calibrated to uplift Test then soil pile stiffness parameters were increased by a factor of 2 for RLT simulations Sinusoidal Loading function applied at pile head to simulate RLT

23. FLAC – Cohesion Block Values y x Cohesion in PSF

24. FLAC - Y-Displacement Contours Apply tension load till equilibrium y x Contours in Feet

25. FLAC – RLT Simulation SI=1.0 y x Load (Pounds) Deformation (Ft) 4.2-inches @ 800,000 lbs 2.2-inches @ 700,000 lbs Cohesion parameter same as Triaxial Test Results

26. FLAC – RLT Simulation SI=1.5 y x Load (Pounds) Deformation (Ft) 1.4-inches @ 800,000 lbs Cohesion parameter 1.5 times Triaxial Test Results

27. FLAC – RLT Simulation SI=2.0 y x Load (Pounds) Deformation (Ft) 1.0-inches @ 800,000 lbs Cohesion parameter 2.0 times Triaxial Test Results

28. RLT & FLAC

29. CONCLUSIONS Classical theoretical values deviate from observed data at higher loads RLT capacity results were about 2.0 X higher than the theoretical values A 1.7 X Strength Increase correlates well with published data Dynamic nature of the RLT mimic seismic conditions

30. CONCLUSIONS (CONT.) Designer could test several piles per day with RLT in cohesive material calibrate material parameters to match the observed data and then apply strength reduction to “Calibrated” parameters and establish “Ultimate Pile Capacities” Lower Factor of Safety could be applied to the “Allowable Pile Capacity”

31. CONCLUSIONS Classical theoretical values deviate from observed data at higher loads RLT capacity results were about 2.0 X higher than the theoretical values A 1.7 X Strength Increase correlates well with published data Dynamic nature of the RLT mimic seismic conditions

32. Richmond BART and UCSF Mission Bay

33. BART RLT

37. UCSF - Test 19A #5 - Davisson

38. UCSF - Test 19A #3 - Davisson

40. UCSF - Test 19A #5 - Davisson

41. UCSF - Test 19A #5 – Chin-Konders - 1

42. UCSF - Test 19A #5 Chin-Konders-2

43. UCSF - Test 19A #5 – Hansen - 1

44. UCSF - Test 19A #5 – Hansen 2

45. UCSF - Test 19A #3 – De Beers

46. N4 West

50. Classical and Finite Difference Method to Estimate pile Capacity Compared With Pile Load Test Results Yogesh Prashar, P.E., GE Force Pulse Conference, DFI January 2012 Oakley, California www.m2consultantsinc.com