Civil Engineering Reference
In-Depth Information
143
_____
x
135.9
1.05 m
Maximum and minimum bearing pressures:
N
(
B
6
e
)
N
(
B
6
e
)
__________
_________
q
q
Eqs. (8.7
a
) and (8.7
b
)
B
2
B
2
Eccentricity
e
1.0
1.05
0.05 m
q
135.9 [2
6 (0.05)]
__________________
78.1 kPa
2
2
q
135.9 [2
6 (0.05)]
__________________
57.8 kPa
2
2
Factor of safety for sliding:
Friction angle between bottom of wall footing and underlying soil
24°
FS
N
tan
P
p
___________
Eq. (10.11)
P
H
N
W
P
v
135.9 kN/m
FS
135.9 tan 24°
4.07
__________________
37.6
1.72
Factor of safety for overturning:
Taking moments about the toe of the wall gives
Overturning moment
P
H
H
__
3
2
P
v
4
__
37.6
23.5 (2)
3.1 kN
m/m
3
Moment of weights
56.4 (1)
56 (1.6)
146 kN
m/m
FS
146
____
3.1
47
Earthquake analysis:
To find
P
AE
,
a
max
____
g
0.20
tan
1
k
h
tan
1
a
max
____
g
tan
1
0.20
11.3° Eq. (10.10)
32°
32°
0°
0°
