Civil Engineering Reference
In-Depth Information
The lateral thrust from the surcharge is a variable, unfavourable action.
P
=
0 238 10 5
.
× × × =
γ
17 8
.
kN
q d
;
Q
(iii) Design effect of actions and design resistance
Sliding
:
Total horizontal thrust R
,
;
=
72 3 17 8
.
+
.
=
90 1
.
kN
h d
=
′
Design resistance R
=
;
tan
δ
=
249 9
.
×
tan
38
° =
195 2
.
kN since
(
δ
φ
)
v d
The GEO limit state requirement for sliding is satisfied and the over-design factor
195 2
90 1
.
.
Γ =
=
2 17
.
Overturning:
×
5
3
+
×
5
2
=
165 . kNm
Destabilising moment M
dst
,
=
72 3
.
17 8
.
Stabilising moment M
stb
,
=
46 0 0 7
.
×
.
+
30 0 1 5 173 9 1 95
.
×
.
+
.
×
.
=
416 3 kNm
.
The GEO limit state requirement for overturning is satisfied since M
dst
<
M
stb
, and the
over-design factor
416 3
165 0
.
.
Γ =
=
2 52
.
Bearing:
From above, destabilising moment
=
165.0 kNm
Stabilising moment:
The weight of the wall, R
v
is now considered as an
unfavourable
action and includes the
surcharge acting on the soil on the heel:
M
=
M
+
M
+
M
stb
stem
base
heel
=
(
46 0 0 7
.
×
.
+
30 0 1 5 173 9 1 95
.
×
.
+
.
×
.
)
×
γ
nfav
+
(
21 0 1 95
.
×
.
)
× =
γ
623 4
.
kNm
G u
;
Q
R
=
(
46 0
.
+
30 0 173 9
.
+
.
)
×
γ
+
21 0
.
× =
γ
368 9
.
kN
v d
;
G unfav
;
Q
623 4 165 0
368 9
.
−
.
Lever arm of R
v ;
,
x
=
=
1 24
.
m within middle t
(
hird of base)
.
Eccentricity e
,
=
1 5 1 24
.
−
.
=
0 26
.
m
R
B
6
e
=
368 9
3 0
.
6
×
0 26
3 0
.
=
v d
;
Maximum bearing pressure
=
1
+
1
+
186 9
.
kPa
B
.
.
The GEO limit state requirement for bearing is satisfied and the over-design factor
250
186 9
Γ =
=
1 34
.
.
2.
Combination 2 (partial factor sets A2
+
M2
+
R1)
The calculations are the same as for Combination 1 except that this time the following partial
. The
.
favourable actions are the same as for Combination 1 since
γ
G; fav
=
1.0.
