Verification of geotechnical reliability using load tests and integrity tests - Risk and Reliability in Geotechnical Engineering - page 536

Table 14.5 Reliability statistics of single driven piles

Coefficient
of variation
COV R

ASD factor
of safety
FOS

Number
of cases

Bias
factor λ R

Reliability
index β Method category Prediction method Reference

2.5
2.5
2.5
2.5
2.5
3.25
2.5
3.25

3.11
2.55
2.39
2.38
2.29
2.11
1.94
1.92

McVay et al. (2000)
McVay et al. (2000)
Paikowsky and Stenersen (2000)
Paikowsky and Stenersen (2000)
McVay et al. (2000)
McVay et al. (2000)
Paikowsky and Stenersen (2000)
Paikowsky and Stenersen (2000)

Dynamic methods
with measurements
(Construction stage)

CAPWAP (EOD, Florida database)
CAPWAP (BOR, Florida database)
CAPWAP (EOD, national database)
CAPWAP (BOR, national database)
Energy approach (EOD, Florida database)
Energy approach (BOR, Florida database)
Energy approach (EOD, national database)
Energy approach (BOR, national database)

44
79
125
162
27
72
128
153

1.60
1.26
1.63
1.16
1.11
0.84
1.08
0.79

0.35
0.35
0.49
0.34
0.34
0.36
0.40
0.37

Static methods
(Design stage)

Alpha method, clay type I
Alpha method, clay type II
Beta method
CPT method
Lambda method, clay type I
Meyerhof's SPT method

-
-
-
-
-
-

1.10
2.34
1.03
1.03
1.02
1.30

0.21
0.57
0.21
0.36
0.41
0.50

2.5
2.5
2.5
2.5
2.5
2.5

3.08
2.72
2.82
1.98

Sidi (1985), Barker et al. (1991)
Sidi (1985), Barker et al. (1991)
Sidi (1985), Barker et al. (1991)
Orchant et al. (1988), Barker
et al. (1991)
Sidi (1985), Barker et al. (1991)
Orchant et al. (1988), Barker
et al. (1991)

1.74
1.92

Source: Zhang, L. M., Tang, W. H. and Ng, C. W. W. 2001. Journal of Geotechnical and Geoenvironmental Engineering ASCE , 127, 1051-1060.
Note: Type I refers to soils with undrained shear strength S u < 50 kPa; Type II refers to soils with S u > 50 kPa.