Civil Engineering Reference
In-Depth Information
10.12
Static analysis:
Use the following equation (Day 1999):
cos
2
______________________________
k
p
)
0.5
]
2
[1
(sin
2
sin
cos
tan
where
friction angle of the soil in front of the retaining wall and
slope inclination
measured from a horizontal plane, where a descending slope in front of the retaining wall
has a negative
value. Although not readily apparent, if
0, the above equation will
give exactly the same values of
k
p
as Eq. (10.4). Inserting
18.4° and
33° into
the above equation, we get
k
p
1.83.
1.83
____
(1.71
10
6
)
9.23
10
5
Resisting moment
3.39
resisting moment
destabilizing moment
9.23
10
5
__________________
_________
FS
7.8
10
5
1.18
Earthquake analysis:
a
max
____
2
k
A
1
⁄
2
H
2
2
(0.295)
1
⁄
2
(0.20)(50
2
)(64)
8690 lb/ft
P
E
1
g
b
1
And
P
E
acts at a distance of
2
3
(
H
D
) above the bottom of the sheet pile wall.
3
(50)
4]
1.10
10
5
Moment due to
P
E
8690 [
1
Total destabilizing moment
7.80
10
5
1.10
10
5
8.90
10
5
1.83
____
Moment due to passive force
3.39
(1.71
10
6
)
9.23
10
5
resisting moment
destabilizing moment
9.23
10
5
__________________
_________
FS
8.90
10
5
1.04
10.13
Static analysis:
(5
2
) (2) (150 lb/ft
3
)
Weight of anchor block
W
7500 lb
Determine the frictional resistance at the top and bottom of the anchor block:
Friction coefficient
2
3
2
3
(33°)
22°
Friction at top of block
N
tan 22°
where
N
(5
2
) (3) (120 lb/ft
3
)
9000 lb
Therefore,
Friction at top of block
N
tan 22°
9000 tan 22°
3640 lb
