Civil Engineering Reference
In-Depth Information
Example 10.4:
Static load tests (to UK National Annex)
A series of static load tests on a set of four bored piles gave the following results:
Test no.
1
2
3
4
Measured load (kN)
382
425
365
412
From an understanding of the ground conditions, it is assumed that the ratio of base
resistance to shaft resistance is 3 : 1. Determine the design compressive resistance of the
ground in accordance with Eurocode 7, Design Approach 1, following the UK National
Annex and assume explicit SLS verification has taken place.
Solution:
382
+
425
+
365
+
412
(
R
c m mean
=
)
=
396
kN
;
4
(
R
; min
=
365
kN
c m
(
R
)
396
1 38
c m
;
mean
ξ
1
R
=
=
=
287
kN
c k
;
.
(
R
)
365
1 15
c m
; min
R
=
=
=
317
kN
c k
;
ξ
2
.
that is
R
=
287
kN i e the minimum value
( . .
)
c ;
Since the ratio of base resistance to shaft resistance is 3 : 1, we have:
Characteristic base resistance, R
b;k
=
287
×
0.75
=
215 kN
Characteristic shaft resistance, R
s;k
=
287
×
0.25
=
72 kN
Design Approach 1, Combination 1:
Partial factor set R1 is used:
R
287
1 0
c k
;
R
=
=
=
287
kN
c d
;
γ
t
.
or
R
R
215
1 0
72
1 0
b k
;
s k
;
R
287
kN
=
+
=
+
=
c d
;
γ
γ
.
.
b
s
Design Approach 1, Combination 2:
Partial factor set R4 is used:
R
287
1 7
c k
;
R
=
=
=
169
kN
c d
;
γ
t
.
