1er Congreso - Seminario Internacional de Fundaciones Profundas - Santa Cruz, Bolivia - 2013

1. International Seminar on Deep Foundations
Seminario Internacional de Fundaciones Profundas
Pile Prediction Event
Evento de Prediccion -- Pilotes
Santa Cruz, Bolivia, April 23 – 25, 2013
Bengt H. Fellenius

9. 0
5
10
15
20
25
DEPTH(m)
1.2 m
17.5 m 2.5 m
15.0m
O-cell
EB
EB
600 mm
2.9 m GW
1.0 m
4.0 m
7.0 m
10.0 m
13.0 m
16.0 m
1.8 m
4.1 m
7.1 m
8.6 m
9.6
m
Ground
surface
Test Pile Configurations and Strain-Gage Levels
360 mm400 mm 600 mm
TP1 TP2 TP3 TP4
"Std" FDP FDP "Std"
+EB +O-cell
+EB
BH1 BH3 BH 4 BH2
0.0 m 400 mm 360 mm 360 mm 450 mm
0.40 m
3.4 m
6.4 m
9.4 m
10.9 m
11.6 m
Purpose of the four tests is to compare the response of a bored piled drilled
with bentonite as opposed to a Full Displacement Pile (FDP) and, also, to
test the effect of placing an Expander Base at the toe of each pile type.

10. 0
5
10
15
20
5 10 15 20 25 30
NORTH-SOUTH
EAST-WEST
BH1 BH3
TP1 TP2 TP3 TP4
Boreholesand Test Piles in Plan
RP1 RP2 RP3 RP4 RP5
RP6 RP7 RP8 RP9 RP10
REFERENCE
BEAM
BH2

12. 0
2
4
6
8
10
12
14
16
18
20
0 10 20 30 40 50
DEPTH(m)
N (blows/0.3m)
SPT1
SPT2
SPT3
0
2
4
6
8
10
12
14
16
18
20
0 5 10 15 20 25 30
DEPTH(m)
WATER CONTENT (%)
0
2
4
6
8
10
12
14
16
18
20
0 20 40 60 80 100
DEPTH(m)
GRAIN SIZE (%)
Fine to Medium Sand
Medium to
Coarse SandFines
Gravel
Zone of Clay and Clayey Sand
(no samples)
BH-1

14. 0
1
2
3
4
5
6
7
8
9
10
11
12
0 10 20 30
CONE STRESS, qc (MPa)
DEPTH(m)
CPT1 CPT2
CPT3 CPT4

15. Bengt’s Rule
Never miss a chance to share a challenge with good friends
The Prediction
Predict the pile-head load-movement curve for the four test piles
and
Determine the capacity of the pile from each load-movement curve
Bengt’s Philosophy
If my prediction is wrong, I expect my friends to forget it.
If I am right, I will not let them forget it!

16. 0
500
1,000
1,500
2,000
2,500
3,000
3,500
4,000
4,500
0 10 20 30 40 50 60
LOAD(KN)
MOVEMENT (mm)
Pile TP1 Load-Movement Predictions

17. Pile TP1 Capacity Evaluations
0
500
1,000
1,500
2,000
2,500
3,000
3,500
4,000
4,500
0 10 20 30 40 50 60
LOAD(KN)
MOVEMENT (mm)

18. 18
RealtiveFrequency
Values
σ = Standard
Deviation
= 671
σ/µ = Coefficient
of Variation,
COV = 0.34
The area between -σ and +σ from the mean
value is 68% of total area
The area between -2σ and +2σ from the mean
value is 90% of total area
Mean, µ
NORMAL DISTRIBUTION
2σ
4σ
= 1976

19. Pile TP1

20. 20
0
500
1,000
1,500
2,000
2,500
3,000
0 25 50 75 100 125 150
LOAD(KN)
MOVEMENT (mm)
UniPile Calculations
TP1
Head
Shaft
Toe
"Capacity"

21. 21
0
100
200
0 10 20 30 40 50 60 70 80 90 100
PREDICTEDCAPACITY
=100
MOVEMENT (mm)
220
130
Fellenius, B.H., 2013. Capacity and load-movement of a CFA pile: A prediction event.
ASCE GeoInstitute Geo Congress San Diego, March 3-6, 2013, Foundation Engineering in
the Face of Uncertainty, ASCE, Reston, VA, James L. Withiam, Kwok-Kwang Phoon, and
Mohamad H. Hussein, eds., Geotechnical Special Publication, GSP 229, pp. 707-719.

22. Pile TP1
Now with the results of the static loading test
0
500
1,000
1,500
2,000
2,500
3,000
3,500
4,000
4,500
0 10 20 30 40 50 60
LOAD(KN)
MOVEMENT (mm)
BHF
Geometric
Mean
260
110
126
COMPILATION OF ALL PREDICTIONS
Capacity
Predicted

23. Pile TP2
0
500
1,000
1,500
2,000
2,500
3,000
3,500
0 10 20 30 40 50 60
LOAD(KN)
MOVEMENT (mm)
BHF
Geometric
Mean
95
63
68
COMPILATION OF ALL PREDICTIONS, TP2
Capacity
Predicted

24. Pile TP2
0
500
1,000
1,500
2,000
2,500
3,000
3,500
0 10 20 30 40 50 60
LOAD(KN)
MOVEMENT (mm)
BHF
Geometric
Mean
95
63
68
COMPILATION OF ALL PREDICTIONS, TP2
Capacity
Predicted
Now with the results of the static loading test

25. Pile TP3
0
1,000
2,000
3,000
4,000
5,000
6,000
0 10 20 30 40 50 60
LOAD(KN)
MOVEMENT (mm)
Geometric
Mean
65
106
COMPILATION OF ALL PREDICTIONS, TP2
Capacity
Predicted

26. 0
1,000
2,000
3,000
4,000
5,000
6,000
7,000
8,000
9,000
10,000
0 10 20 30 40 50 60
LOAD(KN)
MOVEMENT (mm)
82
COMPILATION OF ALL PREDICTIONS
O-cell upward
O-cell upward
Pile TP4
O-cell downward

28. 0
2
4
6
8
10
12
14
16
18
20
0 500 1,000 1,500 2,000 2,500
DEPTH(m)
LOAD (KN)
Pile TP1 – Bored with Bentonite Pile TP2 -- FDP

29. Pile TP2 Pile TP3 – with Expander Base

30. Pile TP1

31. Pile TP2

32. Pile TP3

33. CONCLUSIONS
The shaft resistance of the FDP pile was about twice or more than the
pile drilled with bentonite.
The stiffness of the about 10 m long FDP pile was about equal to or
better than that of the about twice as long pile drilled with bentonite.
The Expander Base provided a significantly increased stiffness to both
the pile drilled with bentonite and the FDP pile.
We need to decide on how we determine pile capacity, or the various
factors of safety and LRFD-values could be rather meaningless.
The prediction event and my participation in the test have been
most enjoyable. I hoped I have been able to convey this to you.
Thank You