902
Proceedings of the 18
th
International Conference on Soil Mechanics and Geotechnical Engineering, Paris 2013
records at the same elevation on the structure and in the free-
field during the Izmit event, showing an amplification of
movement near on the roof of the structure.
Figure 10 presents the recorded settlements at various
locations with respect to the structure, showing larger
settlements in the free-field, which decreased towards the
structure. This settlement pattern was expected due to the
smaller weight of the tunnel compared to the adjacent soil. A
larger settlement of the surrounding soil compared to the tunnel
led to an overall decrease in permanent lateral earth pressures
on the walls after each shaking event. These results are
currently being studied in combination with strain distributions
and direct pressure measurements for different underground
structures and base motions for Test 1 and the subsequent tests.
(a)
(b)
Figure 7: Measured acceleration recordings in the free-field test
compared in the middle and near the container boundary.
Figure 8. Instrumentation layout in Test-1 (prototype scale)
Table 3. Achieved Motions in Test-1
No.
Ground Motion
Achieved
PGA
1
Izmit - Istanbul
0.3
2 Northridge - Sylmar
0.3
3 Northridge - Sylmar
0.8
4 Northridge - Sylmar
1.1
5
Loma - LGPC
1.0
5 CONCLUSIO
ynamic centrifuge
were co ted on scalse-
crete water reservoirs currently
uthern California. The goal of testing was
N
D
m
experiments
nduc
odel buried reinforced con
being designed in so
to verify 2-D and 3-D numerical models of equivalent
underground structures restrained at the top and bottom. The
data from these experiments will help evaluate the effects of
seismic soil-structure-interaction (SSI) on the distribution of
accelerations and lateral earth pressures on underground
structures with different stiffnesses, soil conditions, and input
ground motion characteristics. This paper includes a discussion
of the centrifuge testing plan for evaluating the seismic response
of buried structures, including the container characterization,
development of scale model structures, instrumentation
challenges and preliminary results.
0
50
100
-0.5
0
0.5
ACC7
max = -0.22
0
50
100
-0.5
0
0.5
ACC 2
max = -0.23
0
50
100
-0.5
0
0.5
ACC8
time (s)
max = -0.25
0
50
100
-0.5
0
0.5
ACC 3
max = -0.22
0
50
100
-0.5
0
0.5
ACC9
max = -0.34
0
50
100
-0.5
0
0.5
ACC 4
max = -0.27
Time (s) Time (s)
Figure 9. Acceleration time histories (in prototype “g”) recorded in the
free-field and on the structure during the Izmit event in Test-1.
0
10
20
30
40
50
60
70
80
90
100
-10
-8
-6
-4
-2
2
0
Time (s)
Settlement (cm)
LVDT 1
LVDT2
LVDT3
LVDT4
LVDT5
Figure 10. Settlement recorded at various locations with respect to the
structure in Test-1 during the Izmit event.
6 ACKNOWLEDGEMENTS
The authors w
epartment of
Water and Power for the financial support of this project and the
versity of Colorado Boulder.
l
g,”
15
th
World Conf. on EQ Eng
., Lisbon.
Divis, C.J., Kutter, B.L., Idriss, I.M., Goto, Y., and Matsuda, T.
G
Zurich, Switzerland.
ould like to thank the Los Angeles D
centrifuge facility staff at the Uni
7 REFERENCES
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th
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2
nd
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