Geoscience Reference
In-Depth Information
Fig. 11.23. Charts forthe evaluation of liquefaction settlements of stripfoundations
resting on a cohesive (clay) crust -“strong” seismicexcitations
(ρ
o
/
B
=
0
.
06
)
/
=
.
[
FS
deg
=
.
>
.
,ρ
dyn
=
.
]
, for “strong” seismic shaking.
When the allowable settlement is increased to 15cm (e.g. in the case of a similar steel
structure), theabove
H
-
H
B
1
70
1
50
1
00
5
0cm
/
B
values arefurther reduced to:
-
H
/
B
=
0
.
80
[
FS
deg
=
1
.
00
,ρ
dyn
=
3
.
0cm
<
15
.
0cm
]
for“weak”seismicshaking,
-
H
/
B
=
0
.
70
[
FS
deg
≈
1
.
30
,ρ
dyn
=
15
.
0cm
]
for“strong” seismicshaking
Getting back to the variation of
FS
deg
versus
H
B
in Figure 11.24, it may be also
observed that there is indeed a critical value of the thickness ratio, denoted as
/
(
H
/
B
)
C
thereafter, beyond which the degraded factor of safety maintains a constant value:
5
.
14
C
u
q
FS
max
deg
=
(11.16)
