Pile Foundations - Elements of Soil Mechanics - page 305

Table 10.2B Correlation factors - static load tests
results (from NA to BS EN1997-1:2004, Table A.NA.9).

Number of piles tested

1 2 3 4 ≥ 5

ξ 1 1.55 1.47 1.42 1.38 1.35

ξ 2 1.55 1.35 1.23 1.15 1.08

Table 10.3A Piles in compression: partial factor sets R1, R2, R3 and R4 (from EN1997-1:2004, Tables
A6, A7 and A8).

R1 R2 R3 R4

Partial
factor set Driven Bored CFA All All Driven Bored CFA

Base, γ b 1.0 1.25 1.1 1.1 1.0 1.3 1.6 1.45

Shaft, γ s 1.0 1.00 1.0 1.1 1.0 1.3 1.3 1.30

Total, γ t 1.0 1.15 1.1 1.1 1.0 1.3 1.5 1.40

Table 10.3B Piles in compression: partial factor sets R1, R2, R3 and R4 (from NA to BS EN1997-1:2004,
Tables A.NA.6, A.NA.7 and A.NA.8).

R1 R2 R3 R4 *

Partial
factor set Driven Bored CFA All All Driven Bored CFA

Base, γ b 1.0 1.0 1.0 1.1 1.0 1.7/1.5 2.0/1.7 2.0/1.7

Shaft, γ s 1.0 1.0 1.0 1.1 1.0 1.5/1.3 1.6/1.4 1.6/1.4

Total, γ t 1.0 1.0 1.0 1.1 1.0 1.7/1.5 2.0/1.7 2.0/1.7

* R4: The pairs of values listed in Table 10.3B indicate that there is a choice of value to be used depending on whether
or not explicit verification of the serviceability limit state (i.e. settlement) has been carried out. The higher value is to
be used when no explicit verification is undertaken, and the lower value is used when there is explicit verification.
Explicit verification includes situations where serviceability is verified by load tests on more than 1% of the constructed
piles or situations where settlement is of no concern.

The design compressive resistance of the ground may be derived by either:

R

c k ;

R = γ c d ;

t

or

R R

b k ; s k ;

R = + c d ;

γ γ

b s

where γ b , γ s and γ t are partial factors on base resistance, shaft resistance and the total resistance respec-
tively. The partial factors for piles in compression recommended in Eurocode 7 are given in Table 10.3A
(Eurocode 7, Part 1) or Table 10.3B (UK National Annex).