Civil Engineering Reference
In-Depth Information
FIGURE 8.10
Damage to a warehouse due to lateral movement of a quay wall in Zelenica. The liquefac-
tion of the sand layer was caused by the Monte Negro earthquake on April 15, 1979. (
Reproduced from
Ishihara 1985.
)
Solution for Strip Footing Using Eq. (8.7).
To calculate the factor of safety in terms of
a bearing capacity failure for the strip footing, the following values are used:
Q
P
50 kN/m
for strip footing
e
M
Q
5 kN
m/m
__
__________
50 kN/m
0.10 m
for middle one-third of footing,
e
cannot exceed
0.17 m, and therefore
e
is within middle one-third of footing
Q
(
B
6
e
)
50 [1
(6) (0.1)]
__________
_______________
q
B
2
1
2
80 kN/m
2
[Eq. (8.7)]
T
2.5 m i.e., total thickness of unliquefiable soil layer minus footing
embedment depth
3 m
0.5 m
2.5 m
c
1
s
u
50 kPa
50 kN/m
2
upper cohesive soil layer
c
2
0 kPa
0 kN/m
2
liquefied soil layer
B
1 m
N
c
5.5
using Fig. 8.8 with T/ B
2.5/1.0
2.5 and
c
2
/
c
1
0
