Civil Engineering Reference
In-Depth Information
Equation (10.1):
P
A
1
2
k
A
b
H
2
1
2
(0.333) (9.7) (8
2
)
103 kN/m
Equation (10.3):
P
p
1
2
k
p
t
D
2
Using
b
in place of
t
then gives
P
p
1
2
(3.0) (9.7) (1
2
)
14.6 kN/m
With reduction factor
2, allowable
P
p
7.3 kN/m.
Resultant value of
N
and distance of
N
from the toe of footing:
Total weight of concrete box structure
823 kN/m
Water pressure at bottom of box structure
(8
0.4) (9.81 kN/m
3
)
74.6 kPa
Water force
74.6 (5)
373 kN/m
W
N
buoyant unit weight of wall
823
373
450 kN/m
Take moments about the toe of the wall to determine the location of
N:
8
__
Nx
P
A
3
W
(moment arm)
8
5
__
__
450
x
103
3
450
2
x
850
____
450
1.89 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
5
__
2
1.89
0.61 m
450 [5
6 (0.61)]
________________
q
156 kPa
5
2
q
450 [5
6 (0.61)]
________________
24 kPa
5
2
