4. 25-28 june thessaloniki greece 4th international conference on earthquake geotechnical...
TRANSCRIPT
-
Proceedings of:
Workshops 1, 2, 4
Invited Lectures
Delayed Papers
editor: Kyriazis Pitilakis
4th International Conferenceon Earthquake Geotechnical
Engineering
ARISTOTLE UNIVERSITY OF THESSALONIKILABORATORY OF SOIL MECHANICS, FOUNDATION & GEOTECHNICAL EARTHQUAKE ENGINEEERING
25-28 June Thessaloniki Greece
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Table of Contents
Invited Lectures Presentations TITLE Authors Page
STABILIZATION OF THE LEANING TOWER OF PISA. BEHAVIOUR OF THE TOWER AFTER STABILIZATION WORKS 2001-2004
M. JAMIOLKOWSKY, C. VIGGIANI 1
NEW ORLEANS LEVEE PERFORMANCE IN HURRICANE KATRINA: LESSONS FOR CALIFORNIAS LEVEE SITUATION
R. B. SEED 29
Keynote Lecture Presentation TITLE Authors Page
PILE RESPONSE TO LATERAL SPREADING: FIELD OBSERVATIONS AND CURRENT RESEARCH
R. DOBRY, C. MEDINA, T. ABDOUN, S. THEVANAYAGAM
61
Delayed papers ID TITLE Authors Page
1700 SEISMIC DESIGN LOADS FOR METROPOLITAN SUBWAY TUNNELS: THE CASE OF THESSALONIKI METRO
Kiriazis PITILAKIS, Anastasios ANASTASIADIS, Dimitrios RAPTAKIS, Nikolaos BOUSOULAS, Elena PAPAGEORGIOU
131
WORKSHOP 1: LARGE SCALE FACILITIES, GEOTECHNICAL STRONG MOTION ARRAYS AND EXPERIMENTAL SITES
ID TITLE Authors Page
W1-1005 REFLECTIONS ON THE IMPORTANCE OF THE QUALITY OF THE INPUT MOTION IN SEISMIC CENTRIFUGE TESTS
Jean-Louis CHAZELAS, Gopal SP MADABHUSHI 146
W1-1004 STUDY OF PILE RESPONSE TO LATERAL SPREADING USING PHYSICAL TESTING AND COMPUTATIONAL MODELING
Ricardo DOBRY, Sabanayagam THEVANAYAGAM, Tarek ABDOUN, Ahmed ELGAMAL, Usama EL SHAMY, Mourad ZEGHAL, and Claudia MEDINA
161
W1-1010 TRENDS AND OPPORTUNITIES IN THE FURTHER USE AND DEVELOPMENT OF THE EU LARGE RESEARCH INFRASTRUCTURES FOR EARTHQUAKE ENGINEERING
Michel GERADIN and Fabio TAUCER 174
W1-1006 VISUALIZATION OF LARGE-SCALE SEISMIC DATA RECORDS Falko KUESTER , Tara C. HUTCHINSON, Tung-Ju HSIEH
175
W1-1007 NONLINEAR WAVE PROPAGATION AND TRENDS AT A LARGESCALE CENTRIFUGE FACILITY
Bruce KUTTER and Dan WILSON 187
W1-1011 A 3-D VISUALIZATION SYSTEM FOR LARGE-SCALE EXPERIMENTAL GEOTECHNICAL EARTHQUAKE DATABASES
Jorge MENESES, Masayoshi SATO and Akio ABE 199
W1-1012 15 YEARS OF EUROSEISTEST Kyriazis PITILAKIS, Dimitris RAPTAKIS, Konstantia MAKRA, Francisco CHAVEZ GARCIA, Maria MANAKOU, Pashalis APOSTOLIDIS, George MANOS
211
W1-1008 LARGE-SCALE GEOTECHNICAL SIMULATIONS TO ADVANCE SEISMIC RISK MANAGEMENT FOR PORTS
Glenn J. RIX, Ellen M. RATHJE, Patricia M. GALLAGHER, and Ross W. BOULANGER
225
W1-1009 INSTRUMENTED GEOTECHNICAL SITES: CURRENT AND FUTURE TRENDS
Jamison H. STEIDL 234
W1-1001 DENSE SEISMIC INSTRUMENTATION OF SMALL SOFT BASINS Bill (W.R.) STEPHENSON 246
W1-1003 RECENT DEVELOPMENTS OF GEOSYNTHETIC-REINFORCED SOIL STRUCTURES TO SURVIVE STRONG EARTHQUAKES
Fumio TATSUOKA, Junichi KOSEKI, Masaru TATEYAMA, Daiki HIRAKAWA
256
W1-1002 LARGE-SCALE SHAKE TABLE TESTS FOR EARTHQUAKE GEOTECHNICAL ENGINEERING AT NCREE, TAIWAN
Tzou-Shin UENG, Meei-Ling LIN, Wen-Jong CHANG, Chia-Han CHEN, and Kuo-Lung WANG
274
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WORKSHOP 2: GEOTECHNICAL EARTHQUAKE ENGINEERING RELATED TO MONUMENTS AND HISTORICAL CENTRES
ID TITLE Authors Page
W2-1012 SEISMIC RESPONSE ANALYSIS OF ANCIENT COLUMNS Nikolaos ARGYRIOU, Olga-Joan KTENIDOU, Maria MANAKOU, Pashalis APOSTOLIDIS, Francisco CHAVEZ GARCIA, Kyriazis PITILAKIS
284
W2-1015 DESIGN AND IMPLEMENTATION OF ENGINEERING MEASURES FOR THE PROTECTION OF A HISTORICAL MONUMENT AT THE SEISMIC AREA OF MOUNT ATHOS PENINSULA GREECE
Stavros BANDIS, Christos SCHINAS, Elias BAKASIS 302
W2-1007 SEISMIC RESPONSE OF HISTORICAL CENTERS IN ITALY: SELECTED CASE STUDIES
Antonio COSTANZO, Anna D ONOFRIO, Giuseppe LANZO, Alessandro PAGLIAROLI, Augusto PENNA, Rodolfo PUGLIA, Filippo SANTUCCI DE MAGISTRIS, Stefania SICA, Francesco SILVESTRI, Paolo TOMMASI
319
W2-1001 A RESEARCH ON THE PERFORMANCE OF THE CONCRETE STRUCTURES AND THE REASONS OF THEIR FAILURE IN BAM EARTHQUAKE AND DESIGN SUGGESTIONS
Roozbeh ETTEHAD, Hamed JAHANGIRI 343
W2-1013 UNDERGROUND MONUMENTS (CATACOMBS) IN ALEXANDRIA, EGYPT
Sayed HEMEDA, Kyriazis PITILAKIS, Ioanna PAPAYIANNI, Stavros BANDIS, Mohamed GAMAL
348
W2-1016 EFFECT OF STRONG WIND TO THE CENTRAL TOWER, BAYON, ANGKOR THOM, CAMBODIA
Yoshimori IWASAKI 370
W2-1011 DAMAGES OF EARTHEN STRUCTURES AT ARG-E-BAM CAUSED BY THE EARTHQUAKE OF DEC. 26, 2003, THE CITADEL AT BAM, IRAN
Yoshinori IWASAKI, Mahmoud NEJATI 378
W2-1002 THE RECONSTRUCTION OF THE TEMPLE OF TEMPLE OF ZEUS AT NEMEA: RECENT PROGRESS AND FUTURE PERSPECTIVES
Nicos MAKRIS, Theodoros PSYCHOGIOS 386
W2-1003 SEISMIC PERFORMANCE OF ROCK BLOCK STRUCTURES WITH OBSERVATIONS FROM THE OCTOBER 2006 HAWAII EARTHQUAKE
Edmund MEDLEY, Dimitrios ZEKKOS 398
W2-1005 REGIONAL SUBSIDENCE AND EARTHQUAKES AS THREATS TO ARCHITECTURAL MONUMENTS IN MEXICO CITY
Efrain OVANDO-SHELLEY, Marcia PINTO DE OLIVEIRA, Enrique SANTOYO
410
W2-1004 USING CLASSICAL MONUMENTS FOR THE ASSESSMENT OF PAST EARTHQUAKE SCENARIOS
Ioannis PSYCHARIS 427
W2-1008 SEISMIC PERFORMANCE OF THE 4TH CENTURY A.D., BYZANTINE LAND WALLS OF THE CITY OF THESSALONIKI, GREECE
Anastasios G. SEXTOS, Kosmas C.STYLIANIDIS 439
W2-1010 INFLUENCE OF ENGINEERING AND GEOLOGICAL ENVIRONMENT ON ARCHITECTURES MONUMENTS
Erbol SHAIMERDENOV, Askar ZHUSUPBEKOV, Tursun ZHUNISOV
452
W2-1009 THE INVERSE PROBLEM: MODELLING PAST EARTHQUAKES FROM THEIR EFFECTS ON ANCIENT CONSTRUCTIONS THE CASE OF THE AD365 EAST MEDITERRANEAN EARTHQUAKE
Stathis C. STIROS, Villy A. KONTOGIANNI 457
W2-1014 EARTHQUAKE RESPONSE AND VULNERABILITY ASSESSMENT OF MASONRY STRUCTURES
Costas SYRMAKEZIS, Athanasios ANTONOPOULOS, Olga MAVROULI
465
W2-1006 GROUTING OF THREE-LEAF MASONRY: EXPERIMENTAL EVIDENCE ON COMPRESSIVE AND SHEAR STRENGTH ENHANCEMENT
Elizabeth VINTZILEOU 477
WORKSHOP 4: HOW CAN EARTHQUAKE GEOTECHNICAL ENGINEERING CONTRIBUTE TO SAFER DESIGN OF STRUCTURES TO RESIST EARTHQUAKES?
ID TITLE Authors Page
W4-1001 KEY ISSUES IN THE ANALYSIS OF PILES IN LIQUEFYING SOILS Misko CUBRINOVSKI, Hayden BOWEN 489
W4-1004 STATE OF ART KNOWLEDGE VS. STATE OF PRACTICE IN SEISMIC RISK MITIGATION THE ITALIAN EXPERIENCE AFTER THE 2002 S. GIULIANO EARTHQUAKE
Mauro DOLCE , Giacomo DI PASQUALE , Agostino GORETTI
499
W4-1003 THE CONTRIBUTION OF GEOTECHNICAL ENGINEERING TO SAFER DESIGN OF EARTHQUAKE RESISTANT BUILDING FOUNDATION
Michele MAUGERI, Francesco CASTELLI and Maria Rossella MASSIMINO
511
W4-1002 INFLUENCE OF DYNAMIC LOADS (EARTHQUAKE LOADING AND AIRPLANE CRASHES) ON THE BEARING CAPACITY OF PILES, A CASE STUDY
Jost A. STUDER, Hansjrg GYSI 541
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4th International Conference on Earthquake Geotechnical Engineering
Invited Lectures Presentations
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4th International Conference on Earthquake Geotechnical Engineering
Keynote Lecture Presentation
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PIL
E R
ESP
ON
SE T
O L
AT
ER
AL
PI
LE
RE
SPO
NSE
TO
LA
TE
RA
L
SPR
EA
DIN
G: F
IEL
D O
BSE
RV
AT
ION
S SP
RE
AD
ING
: FIE
LD
OB
SER
VA
TIO
NS
AN
D C
UR
RE
NT
RE
SEA
RC
HA
ND
CU
RR
EN
T R
ESE
AR
CH
61
-
Ack
now
ledg
men
tsA
ckno
wle
dgm
ents
62
-
Kob
e E
arth
quak
e 19
95K
obe
Ear
thqu
ake
1995
63
-
Out
line
Out
line
64
-
Fuka
eham
aFu
kaeh
ama
Isla
nd, K
obe
1995
Isla
nd, K
obe
1995
Miw
a et
al.
(200
0)65
-
Fuka
eham
aFu
kaeh
ama
Isla
nd, K
obe
1995
Isla
nd, K
obe
1995
Usu
oka
et a
l. (2
007)
66
-
Foun
datio
n Sy
stem
Foun
datio
n Sy
stem
Miw
a et
al.
(200
6)67
-
Soil
Prof
ileSo
il Pr
ofile
Miw
a et
al.
(200
6)68
-
Gro
und
Acc
eler
atio
n an
d Po
re
Gro
und
Acc
eler
atio
n an
d Po
re
Pres
sure
Bui
ldup
in L
ique
fied
Lay
erPr
essu
re B
uild
up in
Liq
uefi
ed L
ayer
Miw
a et
al.
(200
6)69
-
Ana
lytic
al M
odel
for
Dyn
amic
Ana
lytic
al M
odel
for
Dyn
amic
Soil
Soil
-- Pile
Pile
-- Str
uctu
re I
nter
actio
n St
ruct
ure
Inte
ract
ion
Miw
a et
al.
(200
6)70
-
Pile
Fai
lure
s at
Dep
th
Pile
Fai
lure
s at
Dep
th ju
stju
stbe
fore
be
fore
L
ique
fact
ion
(Kin
emat
ic E
ffec
t)L
ique
fact
ion
(Kin
emat
ic E
ffec
t)
Miw
a et
al.
(200
6)71
-
Res
pons
e C
ompu
ted
by D
ynam
ic S
oil
Res
pons
e C
ompu
ted
by D
ynam
ic S
oil --
Pile
Pile
-- Str
uctu
res
Ana
lysi
sSt
ruct
ures
Ana
lysi
s
Miw
a et
al.
(200
0, 2
006)
72
-
Les
sons
fro
m th
is C
ase
His
tory
Les
sons
fro
m th
is C
ase
His
tory
Iner
tial
dam
age
to s
up
erst
ruct
ure
an
d p
ile a
t sh
allo
wd
epth
s m
ay o
ccu
r m
uch
bef
ore
liq
uef
actio
nK
inem
atic
dam
age
du
e to
larg
e cy
clic
gro
un
d
def
orm
atio
ns
asso
ciat
ed w
ith
liq
uef
acti
on
ten
ds
to c
on
cen
trat
e at
the
two
inte
rfac
esb
etw
een
liq
uef
ied
an
d n
on
liqu
efie
dla
yers
; it
occ
urs
just
b
efo
re o
r af
ter
soil
liqu
efie
s K
inem
atic
dam
age
du
e to
larg
e p
erm
anen
t g
rou
nd
def
orm
atio
n a
sso
ciat
ed w
ith la
tera
l sp
read
ing
also
ten
ds
to c
on
cen
trat
e at
the
top
an
d b
ott
om
of
liqu
efie
d la
yer;
it d
evel
op
s af
ter
soil
liqu
efie
s
73
-
Sum
mar
ies
of C
ase
His
tori
esSu
mm
arie
s of
Cas
e H
isto
ries
NC
EE
R C
ase
Stu
die
s o
f Ja
pan
ese
and
U.S
. E
arth
qu
akes
(Ham
ada
and
OR
ou
rke;
OR
ou
rke
and
Ham
ada,
199
2)T
wo
Sp
ecia
l Iss
ues
on
Ko
be
Ear
thq
uak
e o
f S
oils
an
d F
ou
nd
atio
ns
Jou
rnal
, 199
6 an
d 1
998
To
kim
atsu
(199
9)D
ob
ryan
d A
bd
ou
n(2
001)
Ore
go
n S
tate
Un
iver
sity
Rep
ort
(Dic
ken
son
et
al.,
2002
)Is
hih
ara
(200
3)U
. Cal
ifo
rnia
Dav
is R
epo
rt (
Bo
ula
ng
er e
t al.,
200
3)B
hat
tach
arya
et
al. (
2004
)P
roc.
Wo
rksh
op
U. C
alif
orn
ia D
avis
(Bo
ula
ng
er
and
To
kim
atsu
, 200
5)
74
-
Fre
e fi
eld
gro
un
d d
efo
rmat
ion
Dve
ry im
po
rtan
t p
aram
eter
S
pat
ial v
aria
tion
of
Du
nd
er s
tru
ctu
re m
ay
con
trib
ute
to
dam
age
To
p o
f pile
s m
ay m
ove
ab
ou
t sa
me
as D
, or
mu
ch le
ss if
ver
y st
iff f
ou
nd
atio
n (
hig
h E
I, p
ile
gro
up
s, b
atte
r p
iles,
su
per
stru
ctu
ralc
on
stra
ints
)If
shal
low
no
nliq
uef
ied
cru
st a
bo
ve li
qu
efie
d
laye
r, p
assi
ve t
hru
st o
f th
at c
rust
is k
ey fa
cto
rD
amag
ing
max
imu
m b
end
ing
mo
men
ts o
ccu
r at
to
p /
bo
tto
m b
ou
nd
arie
s o
f liq
uef
ied
laye
r Is
pile
bu
cklin
g in
liq
uef
ied
laye
r a
pro
ble
m?
75
-
76
-
Som
e U
nsol
ved
Eng
inee
ring
Que
stio
ns
Som
e U
nsol
ved
Eng
inee
ring
Que
stio
ns
77
-
Ong
oing
Res
earc
h, R
esea
rch
Too
lsO
ngoi
ng R
esea
rch,
Res
earc
h T
ools
In-d
epth
stu
die
s o
f ca
se h
isto
ries
(m
ost
ly in
Ja
pan
) u
sin
g a
dva
nce
d te
chn
olo
gie
sF
ield
test
s w
ith
bla
stin
g (
Ro
llin
s et
al.,
200
5;
Ash
ford
et
al.,
2006
)L
arg
e-sc
ale
1 g
sh
akin
g te
sts
in J
apan
an
d U
.S.
(6m
tal
l in
clin
ed la
min
ar b
oxe
s), u
se o
f ad
van
ced
se
nso
rsS
mal
l-sca
le c
entr
ifug
e te
stin
g (
Jap
an, U
.S. a
t U
C
Dav
is a
nd
RP
I, U
K a
t Cam
bri
dg
e U
.)U
se o
f ad
van
ced
IT to
ols
fo
r d
ata
inte
gra
tion
, sy
stem
iden
tific
atio
n a
nd
vis
ual
izat
ion
sN
um
eric
al s
imu
latio
ns
and
an
alys
es (D
EM
, FE
M,
dyn
amic
an
d s
tati
c p
-y, l
imit
eq
uili
bri
um
/ p
ush
ove
r an
alys
es)
78
-
Out
line
Out
line
79
-
80
-
81
-
82
-
Out
line
Out
line
83
-
RPI
150
gR
PI 1
50g --
ton
Cen
trif
uge
ton
Cen
trif
uge
84
-
85
-
cem
ente
d sa
ndSl
ight
ly
Slig
htly
cem
ente
d sa
nd T=3
0sec
Nev
ada
sand
(Dr=
40%
)
T=2
0sec
T=1
5sec
-300
-200
-100
010
020
030
040
0
Soil depth (m)
0 2 4 6 8 10
Pile
Ben
ding
Mom
ent P
rofi
les
Dur
ing
Pile
Ben
ding
Mom
ent P
rofi
les
Dur
ing
Shak
ing
Shak
ing
86
-
87
-
88
-
89
-
90
-
Out
line
Out
line
91
-
92
-
Gro
und
and
Pile
Res
pons
ean
d Pi
le R
espo
nse
Disp. (cm)Disp. (cm) Moment (kN-m)
93
-
94
-
95
-
96
-
Max
imum
ben
ding
mom
ent p
rofi
les
in s
ingl
e pi
le te
sts:
1g
Max
imum
ben
ding
mom
ent p
rofi
les
in s
ingl
e pi
le te
sts:
1g
test
(w
ater
) an
d ce
ntri
fuge
test
s (w
ater
and
vis
cous
flu
id)
test
(w
ater
) an
d ce
ntri
fuge
test
s (w
ater
and
vis
cous
flu
id)
Height [m
97
-
Dis
tanc
e [m
]
Distance [m]
98
-
Com
pari
son
betw
een
cent
rifu
ge a
nd
Com
pari
son
betw
een
cent
rifu
ge a
nd
full
full
-- sca
le s
haki
ng ta
ble
test
res
ults
scal
e sh
akin
g ta
ble
test
res
ults
99
-
100
-
101
-
102
-
Max
imum
ben
ding
mom
ent p
rofi
les
in s
ingl
e pi
le te
sts:
1g
Max
imum
ben
ding
mom
ent p
rofi
les
in s
ingl
e pi
le te
sts:
1g
test
(w
ater
) an
d ce
ntri
fuge
test
s (w
ater
and
vis
cous
flu
id)
test
(w
ater
) an
d ce
ntri
fuge
test
s (w
ater
and
vis
cous
flu
id)
Height [m
103
-
104
-
Out
line
Out
line
105
-
Rec
ent R
esul
ts f
rom
1g
Tes
t on
Lat
eral
R
ecen
t Res
ults
fro
m 1
g T
est o
n L
ater
al
Spre
adin
g Sp
read
ing
106
-
107
-
108
-
109
-
Depth (m)
110
-
111
-
Acceleration (g)
112
-
SAA
SA
A v
svsR
ing
Acc
eler
omet
erR
ing
Acc
eler
omet
er3m
Dep
th3m
Dep
th
113
-
SAA
SA
A v
svsPo
tent
iom
eter
Po
tent
iom
eter
D
ispl
acem
ent a
t Sur
face
Dis
plac
emen
t at S
urfa
ce
114
-
Inpu
t Bas
e E
xcita
tion
Inpu
t Bas
e E
xcita
tion
(dis
plac
emen
t of
base
)(d
ispl
acem
ent o
f ba
se)
Deflection (cm)
Bas
e E
xcita
tion
115
-
Pore
Pre
ssur
e D
evel
opm
ent
Pore
Pre
ssur
e D
evel
opm
ent
Depth (m)
116
-
Lat
eral
Spr
eadi
ngL
ater
al S
prea
ding
Deflection (cm)
117
-
Lat
eral
Spr
ead
Initi
atio
n L
ater
al S
prea
d In
itiat
ion
--11
Deflection (cm)
Depth (m)
118
-
Lat
eral
Spr
ead
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120
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121
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4th International Conference on Earthquake Geotechnical Engineering
June 25-28, 2007 Keynote Lecture No.4
PILE RESPONSE TO LATERAL SPREADING: FIELD OBSERVATIONS AND CURRENT RESEARCH
RICARDO DOBRY1
CLAUDIA MEDINA TAREK ABDOUN
SABANAYAGAM THEVANAYAGAM
LIST OF REFERENCES
Abdoun, T. (1997). Modeling of Seismically Induced Lateral Spreading of Multi-layered Soil and its Effect on Pile Foundations, Ph.D. Thesis, Rensselaer Polytechnic Institute, Troy, NY.
Abdoun, T., and Dobry, R. (2002). Evaluation of Pile Foundation Response to Lateral Spreading, Soil Dyn Earthq Eng, Vol. 22, No. 9, pp. 1051-1058.
Abdoun, T., Dobry, R., ORourke, T.D., and Goh, S.H. (2003). Pile Response to Lateral Spreads: Centrifuge Modeling, J Geotech Geoenviron Eng, Vol. 129, No. 10, pp. 869-878.
Abdoun, T., Dobry, R., ORourke, T.D., and Goh, S.H. (2005). Closure to Pile Response to Lateral Spreads: Centrifuge Modeling, J Geotech Geoenviron Eng, Vol. 131, No. 4, pp. 532-534.
Abdoun, T., Dobry, R., Zimmie, T., Zeghal, M., and Gallagher, P. (2005). Centrifuge Research of Countermeasures to Protect Pile Foundations Against Liquefaction-induced Lateral Spreading, Journal of Earthquake Engineering, Vol. 9, Special Issue 1, pp. 105-125.
Abdoun, T., Danisch, L., and Ha, D. (2005). Advanced Sensing for Real-Time Monitoring of Geotechnical Systems, ASCE Geotech Special Public No. 138 Site Characterization and Modeling (Ellen M. Rathje, ed.), Proc Geo-Frontiers 2005 Conference, January 24-26, 2005, Austin, TX.
Abdoun, T., Danisch, L., Ha, D., and Bennett, V. (2006). Advanced Sensing for Real-Time Monitoring of Geotechnical Systems, TRB 85th Annual Meeting, January 22-26, 2006, Washington, DC.
Abdoun, T., Abe, A., Bennett, V., Danisch, L., Sato, M., Tokimatsu, K., and Ubilla, J., (2007). Wireless Real Time Monitoring of Soil and Soil-Structure Systems, Geotech Spec Publ No. 161 Embankments, Dams, and Slopes: Lessons From the New Orleans Levee Failures and Other Current Issues (F. Silva-Tulla and P. Nicholson, eds.), Proc GeoDenver 2007 Conference: New Peaks in Geotechnics, February 18-21, 2007, Denver, CO.
Adalier, K. (1996) Mitigation of Earthquake Induced Liquefaction Hazards, Ph.D. Thesis, Rensselaer Polytechnic Institute, Troy, NY.
1 Professor, Department of Civil and Environmental Engineering, Rensselaer Polytechnic Institute, Troy, NY, E-mail: [email protected]
122
-
Ashford, S.A., Juirnarongrit, T., Sugano, T., and Hamada, M. (2006) Soil-Pile Response to Blast-Induced Lateral Spreading. I: Field Test, J Geotech Geoenviron Eng, Vol. 132, No. 2, pp. 152-162.
Bartlett, S.F., and Youd, T.L. (1992). Case Histories of Lateral Spreads Caused by the 1964 Alaska Earthquake, Ch. 2 of Case Studies of Liquefaction and Lifeline Performance During Past Earthquakes, Vol. 2: United States Case Studies (ORourke and Hamada, eds.), NCEER, SUNY-Buffalo, Buffalo, NY, Tech. Rept. NCEER-92-0002, pp. 2.1-2.127
Beavers, J.E., (ed.) (1991). Costa Rica Earthquake Reconnaissance Report, Earthquake Spectra, EERI, Supplement B, Vol. 7, 127 pages.
Benuzca, L. (ed.) (1990). Loma Prieta Earthquake Reconnaissance Report, Earthquake Spectra, EERI and NRC, Supplement to Vol. 6, 448 pages.
Berrill, J.B., Christensen, S.A., Keenan, R.J., Okada, W., and Pettinga, J.K. (1997). Lateral-Spreading Loads on a Piled Bridge Foundation, Seismic Behavior of Ground and Geotechnical Structures, (Seco E. Pinto, ed.), Balkema, Rotterdam, pp. 176-183.
Bhattacharya, S., Madabhushi, S.P.G., and Bolton, M.D. (2003). Pile Instability During Earthquake Liquefaction, ASCE Engineering Mechanics Conference EM2003, July 16-18, 2003, Seattle, WA.
Bhattacharya, S., and Bolton, M.D. (2004). Errors in Design Leading to Pile Failures During Seismic Liquefaction, Proc 5th International Conference on Case Histories in Geotechnical Engineering, April 13-17, 2004, New York, NY.
Bhattacharya, S., Madabhushi, S.P.G., and Bolton, M.D. (2004). An Alternative Mechanism of Pile Failure Deposits During Earthquakes, Geotechnique, Vol. 54, No. 3, pp. 203-213.
Bhattacharya, S., Madabhushi, S.P.G., and Bolton, M.D. (2005). Closure to An Alternative Mechanism of Pile Failure Deposits During Earthquakes, Geotechnique, Vol. 55, No. 3, p. 263.
Boulanger, R.W., Mejia, L.H., and Idriss, I.M. (1997). Liquefaction at Moss Landing During Loma Prieta Earthquake, Journal of Geotechnical and Geoenvironmental Engineering, Vol. 123, No.5, pp.453-467.
Boulanger, R.W., Meyers, M.W., Mejia, L.H., and Idriss, I.M. (1998). Behavior of a Fine-grained Soil During the Loma Prieta Earthquake, Canadian Geotechnical Journal, Vol. 35, pp.146-158.
Boulanger, R.W., Kutter, B.L, Brandenberg, S.J., Singh, P., and Chang, D. (2003). Pile Foundations in Liquefied and Laterally Spreading Ground During Earthquakes: Centrifuge Experiments and Analyses, Report No. UCD/CGM-03/01, Center for Geotechnical Modeling, University of California, Davis, CA, 205 pages.
Boulanger, R.W. and Tokimatsu, K., eds. (2006). Proceedings Workshop on Seismic Performance and Simulation of Pile Foundations in Liquefiable and Laterally Spreading Ground, March 16-18, 2005, University of California, Davis, CA, ASCE Geotech Special Public No. 145, pp. 50-60.
Brandenberg, S.J., Boulanger, R.W., and Kutter, B.L. (2005). Discussion of Pile Response to Lateral Spreads: Centrifuge Modeling by Dobry et al., J Geotech Geoenviron Eng, Vol. 131, No. 4, pp. 529-531.
Brandenberg, S.J., Boulanger, R.W., Kutter, B.L., and Chang, D. (2005). Behavior of Pile Foundations in Laterally Spreading Ground During Centrifuge Tests, J Geotech Geoenviron Eng, Vol. 131, No. 11, pp. 1378-1391.
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Brandenberg, S.J., Boulanger, R.W., Kutter, B.L., and Chang, D. (2007). Liquefaction-Induced Softening of Load Transfer Between Pile Groups and Laterally Spreading Crusts, J Geotech Geoenviron Eng, Vol. 133, No. 1, pp. 91-103.
Cubrinovski, M., Kokusho, T., and Ishihara, K. (2004). Interpretation From Large-Scale Shake Table Tests on Piles Subjected to Spreading of Liquefied Soils, Proc 11th Intl Conf on Soil Dyn and Earthq Eng, January 7-9, University of California, Berkeley, CA, Vol. 2, pp. 463-470.
Cubrinovski, M., Kokusho, T., and Ishihara, K. (2006). Interpretation From Large-Scale Shake Table Tests on Piles Undergoing Lateral Spreading in Liquefied Soils, J of Soil Dyn and Earthq Eng, Vol. 26, pp. 275-286.
Dale, G. (2002). Prediction of Pile Bending Response to Lateral Spreading by Elastoplastic Analysis Validated by Centrifuge Tests, M.S. Thesis, Rensselaer Polytechnic Institute, Troy, NY.
Dickenson, S.E., McCullough, N.J., Barkau, M.G., and Wavra, B.J. (2002) Assessment and Mitigation of Liquefaction Hazards to Bridge Approach Embankments in Oregon, Final Report SPR 361, Oregon Department of Transportation and Federal Highway Administration, 272 pages.
Dobry, R., and Abdoun, T. (1998). Post-triggering Response of Liquefied Sand in the Free Field and Near Foundations, Proc ASCE Geotechnical Earthquake Engineering and Soil Dynamics III, Seattle, WA, August 3-6 1998, Vol. 1, pp. 270-300.
Dobry, R., and Abdoun, T. (2001). Recent Studies on Seismic Centrifuge Modeling of Liquefaction and its Effect on Deep Foundation, State-of-the-Art Paper, Proc 4th Int Conf on Recent Advances in Geotech Earthq Eng and Soil Dyn (S. Prakash, ed.), Paper SOAP 3, Vol. 2, March 26-31, 2001, San Diego, CA, 30 pages.
Dobry, R., Taboada, V., and Liu, L. (1995). Centrifuge Modeling of Liquefaction Effects During Earthquakes, Proc 1st Int Conf on Earthq Geotech Eng (IS-Tokyo), Tokyo, Japan, Keynote Lecture, pp. 1291-1324.
Dobry, R., Abdoun, T., ORourke, T.D., and Goh, S.H. (2003). Single Piles in Lateral Spreads: Field Bending Moment Evaluation, J Geotech Geoenviron Eng, Vol. 129, No. 10, pp. 879-889.
Dobry, R., Abdoun, T., ORourke, T.D., and Goh, S.H. (2005). Closure to Single Piles in Lateral Spreads: Field Bending Moment Evaluation,. J Geotech Geoenviron Eng, Vol. 131, No. 4, pp. 532-534.
Dobry, R., Thevanayagam, S., Abdoun, T., Elgamal, A., El Shamy, U., Zeghal, M., and Medina, C. (2007). Study of Pile Response to Lateral Spreading Using Physical Testing and Computational Modeling, Proc. 4th Intl Conf Earthquake Geotechnical Engineering, Thessaloniki, Greece, June 25-28.
Dungca, J.R., Kuwano, J., Saruwatari, T., Izawa, J., Suzuki, H., and Tokimatsu, K. (2004). Shaking Table Tests on the Lateral Response of a Pile Buried in Liquefied Sand, Proc 11th Intl Conf on Soil Dyn and Earthq Eng, January 7-9, University of California, Berkeley, CA, Vol. 2, pp. 471-477.
Dungca, J.R., Kuwano, J., Takahashi, A., Saruwatari, T., Izawa, J., Suzuki, H., and Tokimatsu, K. (2006). Shaking Table Tests on the Lateral Response of a Pile Buried in Liquefiable Sand, J of Soil Dyn and Earthq Eng, Vol. 26, pp. 287-295.
124
-
Elgamal, A., Zeghal, M., Taboada, V., and Dobry, R. (1996). Analysis of Site Liquefaction and Lateral Spreading Using Centrifuge Testing Records, Soils and Foundations, JGS, Vol. 36, No. 2, pp. 111-121.
Elgamal, A., Parra, E., Yang, Z. and Adalier, K. (2002). Numerical Analysis of Embankment Foundation Liquefaction Countermeasures, J Earthq Eng, Vol. 6, No. 4, pp. 447-471.
Elgamal, A., Yang, Z., and Parra, E. (2002). Computational modeling of Cyclic Mobility and Post-Liquefaction Site Response, J of Soil Dyn and Earthq Eng, Vol. 22, Issue 4, pp. 259-271.
Elgamal, A., Yang, Z., Parra, E., and Ragheb, A. (2003). Modeling of Cyclic Mobility in Saturated Cohesionless Soils, Int J of Plast, Vol. 19, Issue 6, pp. 883-905.
Elmekati, A., and Zeghal, M. (2007). Systen Identification Analysis of Test LG-0, Internal Progress Report, Rensselaer Polytechnic Institute, Troy, NY.
Finn, W.D.L. (2004). An Overview of the Behavior of Pile Foundations in Liquefiable and Non-Liquefiable Soils during Earthquake Excitation, Ishihara Lecture, Proc 11th Intl Conf on Soil Dyn and Earthq Eng, January 7-9, University of California, Berkeley, CA, Vol. 1, pp. 57-67.
Gonzalez, L., Abdoun, T., and Dobry, R. (2006). Effect of Soil Permeability on Centrifuge Modeling of Pile Response to Lateral Spreading, ASCE Geotech Special Public No. 145 (Boulanger and Tokimatsu, eds.), Proc Workshop on Seismic Performance and Simulation of Pile Foundations in Liquefiable and Laterally Spreading Ground, March 16-18, 2005, University of California, Davis, CA, pp. 50-60.
Gonzalez, L., Abdoun, T., and Dobry, R. (2007). Effect of Soil Permeability on Centrifuge Modeling of Pile Response to Lateral Spreading, J Geotech Geoenviron Eng (accepted).
Guo, W.D., and Ghee, E.H. (2006). Behavior of Axially Loaded Pile Groups Subjected to Lateral Soil Movement, ASCE Geotech Special Public No. 153 Foundation Analysis and Design: Innovative Methods (Parsons, R.L., Zhang, L., Guo, W.D., Phoon, K.K., and Yang, M., eds.), Proc Geoshanghai 2006 Conference, June 6-8, 2006, Shanghai, China.
Haigh, S.K., and Madabhushi, S.P.G. (2006). The Effect of Pile Flexibility on Pile-Loading in Lateral Spreading Slopes, ASCE Geotech Special Public No. 145 (Boulanger and Tokimatsu, eds.), Proc Workshop on Seismic Performance and Simulation of Pile Foundations in Liquefiable and Laterally Spreading Ground, March 16-18, 2005, University of California, Davis, CA, pp. 24-37.
Hamada, M. (1992). Large Ground Deformations and Their Effects on Lifelines: 1964 Niigata Earthquake, Ch. 3 of Case Studies of Liquefaction and Lifeline Performance During Past Earthquake, Vol. 1: Japanese Case Studies (Hamada and ORourke, eds.), NCEER, SUNY-Buffalo, Buffalo, NY, Tech. Rept. NCEER-92-0001, pp. 3.1-3.123.
Hamada, M. (1992). Large Ground Deformations and Their Effects on Lifelines: 1983 Nihonkai-Chubu Earthquake, Ch. 4 of Case Studies of Liquefaction and Lifeline Performance During Past Earthquake, Vol. 1: Japanese Case Studies (Hamada and ORourke, eds.), NCEER, SUNY-Buffalo, Buffalo, NY, Tech. Rept. NCEER-92-0001, pp. 4.1-4.85.
Hamada, M., and ORourke, T.D. (eds.), (1992). Case Studies of Liquefaction and Lifeline Performance During Past Earthquakes. Vol. 1: Japanese Case Studies, NCEER, SUNY-Buffalo, Buffalo, NY, Tech. Rept. NCEER-92-0001.
125
-
Hamada, M., Yasuda, S., Isoyama, R., and Emoto, K. (1986). Study on Liquefaction Induced Permanent Ground Displacement, Research Committee Report, Association for the Development of Earthquake Prediction, Tokyo, Japan, 87 pages.
Hamada, M., R. Isoyama, K. Wakamatsu, (1995). The 1995 Hyogoken-Nanbu (Kobe) earthquake: Liquefaction, Ground Displacement and Soil Condition in Hanshin Area, Assoc. for Development of Earthquake Prediction, School of Science and Engineering, Waseda University, and the Japan Engineering Consultants, Publ. by the Assoc. for Development of Earthquake Prediction, 194 pages.
Hamada, M., Wakamatsu, K., and Ando, T. (1996). Liquefaction-Induced Ground Deformation and its Caused Damage During the 1995 Hyogeken-Nanbu Earthquake, Proc. 6th Japan-U.S. Workshop on Earthquake Resistant Design of Lifeline Facilities and Countermeasures Against Soil Liquefaction (Hamada and ORourke, eds.), NCEER, SUNY-Buffalo, Buffalo, NY, Tech. Rept. NCEER-96-0012, Vol. 1, pp. 137-152.
Harada, N., Towhata, I., Takatsu, T., Tsunoda, S., and Sesov, V. (2004). Development of New Drain Method for Protection of Existing Pile Foundations From Liquefaction Effects, Proc 11th Intl Conf on Soil Dyn and Earthq Eng, January 7-9, University of California, Berkeley, CA, Vol. 2, pp. 498-505.
Harada, N., Towhata, I., Takatsu, T., Tsunoda, S., and Sesov, V. (2006). Development of New Drain Method for Protection of Existing Pile Foundations From Liquefaction Effects, J of Soil Dyn and Earthq Eng, Vol. 26, pp. 297-312.
He, L., Elgamal, A., Abdoun, T., Abe, A., Dobry, Meneses, J., Sato, M., and Tokimatsu, K. (2006). Lateral Load on Piles Due to Liquefaction-Induced Lateral Spreading During 1G Shake Table Experiments, Proc. 8th U.S. National Conf on Earthq Eng, April 18-22, 2006, San Francisco, CA, Paper No. 881.
Hwang, J.I., Kim, C.Y., Chung, C.K., and Kim, M.M. (2004). Behavior of a Single Pile Subjected to Flow of Liquefied Soil in an Infinite Slope, Proc 11th Int Conf on Soil Dyn and Earthq Eng, Vol. 2, pp. 573-580.
Idriss, I.M., and Boulanger, R.W. (2004). Semi-empirical Procedures for Evaluating Liquefaction Potential During Earthquakes, Proc 11th Intl Conf on Soil Dyn and Earthq Eng, January 7-9, University of California, Berkeley, CA, Vol. 1, pp. 32-56.
Ishihara, K. (2003). Liquefaction-induced Lateral Flow and its Effects on Foundation Piles, Proc. Fifth Natl Conf on Earthquake Engineering, Istanbul, Turkey, May 26-30, Invited Lecture, 28 pages.
Ishihara, K., Yasuda, S., and Nagase, H. (1996). Soil Characteristics and Ground Damage, Soils and Foundations Special Issue on Geotechnical Aspects of the January 17 1995 Hyogoken-Nambu Earthquake, JGS, Special Vol. January, pp. 109-118.
Iwasaki, T. (1986). Soil Liquefaction Studies in Japan, Technical Memorandum of PWRI No. 2239, Public Works Research Institute, Ministry of Construction, Japan, 143 pages.
Juirnarongrit, T., and Ashford, S.A. (2006). Soil-Pile Response to Blast-Induced Lateral Spreading. II: Analysis and Assessment of the p-y Method, J Geotech Geoenviron Eng, Vol. 132, No. 2, pp. 163-172.
Japanese Geotechnical Society (1998). Special Issue of Soils and Foundations on the Effects of the 1995 Hyogoke-Nambu Earthquake.
126
-
Kachadoorian, R. (1968). Effects of the Earthquake of March 27, 1964, on the Alaska Highway System, U.S. Geological Survey Professional Paper 545-C, U.S. Geological Survey.
Kagawa, T., Sato, M., Minowa, C., Abe, A., and Tazoh, T. (2003) Centrifuge Simulations of Large-Scale Shaking Table Tests: Case Studies, J Geotech Geoenviron Eng, Vol. 130, No. 7, pp. 663-672.
Knappett, J.A., and Madabhushi, S.P.G. (2006). Modelling Effects of Axial Load on Behaviour of Pile Groups in Laterally-Spreading Soil,. Proc 6th International Conference on Physical Modelling in Geotechnics, August 4-6, 2006, Hong Kong, pp. 1007-1012.
Kawashima, K., Shimizu, K., Mori, S., Takagi, M., Susuki, N, and Nakamura, S. (1988). Analytical Studies on Damage to Bridges and Foundation Piles Caused by Liquefaction-Induced Permanent Ground Displacement, Proc. Japan-U.S. Workshop on Liquefaction, Large Ground Deformation and Their Effect on Lifeline Facilities, Nov. 16-19, Tokyo, Japan, Association for the Development of Earthquake Prediction, (Japan) and NCEER (U.S.), pp. 99-117.
Koyamada, K., Miyamato, Y., and Tokimatsu, K. (2006). Field Investigation and Analysis Study of Damage Pile Foundation During the 2003 Tokachi-Oki Earthquake, ASCE Geotech Special Publ No. 145 (Boulanger and Tokimatsu, eds.), pp. 97-108.
Lin S., Tseng, Y., Chiang, C., and Hung, C. (2006). Damage of Piles Caused by Lateral Spreading-Back Study of Three Cases, ASCE Geotech Special Public No. 145 (Boulanger and Tokimatsu, eds.), Proc Workshop on Seismic Performance and Simulation of Pile Foundations in Liquefiable and Laterally Spreading Ground, March 16-18, 2005, University of California, Davis, CA, pp. 121-133.
Matsui, T. and K. Oda. (1996). Foundation Damage to Structures, Soils and Foundations Special Issue on Geotechnical Aspects of the January 17 1995 Hyogoken-Nambu Earthquake, JGS, Special Vol., January, pp. 189-200.
McCulloch, D.S., and Bonilla, M.G. (1970). Effects of the Earthquake of March 27, 1964 on the Alaska Railroad, U.S. Geological Survey Professional Paper 545-D, U.S. Geological Survey.
Miwa, S., Ikeda, T., and Sato, T. (2006). Damage Process of Pile Foundation in Liquefied Ground During Strong Ground Motion, J of Soil Dyn and Earthq Eng, Vol. 26, pp. 325-336.
Mizuno, H. (1987). Pile Damage During Earthquakes in Japan (1923-1983), Proc ASCE Session on Dynamic Response of Pile Foundations (T. Nogami ed.), April 27, 1987, Atlantic City, pp. 53-77.
ORourke, T.D., and Hamada, M. (eds.), (1992). Case Studies of Liquefaction and Lifeline Performance During Past Earthquakes. Vol. 2: United States Case Studies, NCEER, SUNY-Buffalo, Buffalo, NY, Tech. Rept. NCEER-92-0002.
O'Rourke, T.D., and Pease, J.W. (1992). Large Ground Deformations and Their Effects on Lifeline Facilities: 1989 Loma Prieta Earthquake, Ch. 5 of Case Studies of Liquefaction and Lifeline Performance During Past Earthquake, Vol. 2: United States Case Studies (ORourke and Hamada, eds.), NCEER, SUNY-Buffalo, Buffalo, NY, Tech. Rept. NCEER-92-0002, pp. 5.1-5.85.
Parra, E. (1996). Numerical Modeling of Liquefaction and Lateral Ground Deformation Including Cyclic Mobility and Dilation Response in Soil Systems, Ph.D. Thesis, Rensselaer Polytechnic Institute, Troy, NY.
127
-
Pyke, R. (2003). Discussion of Liquefaction Resistance of Soils: Summary Report from the 1996 NCEER and 1998 NCEER/NSF Workshops on Evaluation of Liquefaction Resistance of Soils by Youd et al., J Geotech Geoenviron Eng, Vol. 129, No. 3, pp. 283-284.
Radwan, H., and Abdoun, T. (2006). 3D Data Viewer of Centrifuge Physical Models, Geotech Special Publ Proc GeoCongress 2006 Conference: Geotechnical Engineering in the Information Technology Age (D.J. DeGroot, J.T. DeJong, J.D. Frost, and L.G. Baise, eds.), February 26-March 1, 2006, Atlanta, GA.
Ramos, R. (1999). Centrifuge Study of Bending Response of Pile Foundation to a Lateral Spread Including Restraining Effect of Superstructure, Ph.D. Thesis, Rensselaer Polytechnic Institute, Troy, NY.
Ross, G.A., Seed, H.B., and Migliaccio, R.R. (1973). Performance of Highway Bridge Foundations, The Great Alaska Earthquake of 1964, Engineering Volume, National Academy of Sciences, Washington, D.C., pp. 190-242.
Seed, R.B., Dickenson, S.E., Riemer, M.F., Bray, J.D., Sitar, N., Mitchell, J.K., Idriss, I.M., Kayen, R.E., Kropp, A., Harder Jr., L.F., and Power, M.S. (1990). Preliminary Report on the Principal Geotechnical Aspects of the October 17, 1989 Loma Prieta Earthquake, Report No. UCB/EERC-90/05, Earthquake Engineering Research Center, University of California at Berkeley, Berkeley, CA., 139 pages.
Shea, G.H., (ed.) (1991). Costa Rica Earthquake Reconnaissance Report, Earthquake Spectra, EERI, Supplement B, Vol. 7, Chapter 6 Bridges, 127 pages.
Shengcong, F., and Tatsuoka, F. (1984). Soil Liquefaction During Haicheng and Tangshan Earthquakes in China; A Review, Soils and Foundations, Vol. 24, No. 4, pp 11-29.
Shenthan T. (2001). Factors Affecting Liquefaction Miitigation in Silty Soils Using Stone Columns, MS Thesis, University at Buffalo, SUNY, NY, p. 129.
Shibata, T., F. Oka, and Y. Ozawa. (1996). Characteristics of Ground Deformation due to Liquefaction, Soils and Foundations Special Issue on Geotechnical Aspects of the January 17 1995 Hyogoken-Nambu Earthquake, JGS, Special Vol. January, pp. 65-80.
Stewart, H.E., Miura, F., and ORourke, T.D. (1988). Pile Damage Due to Large Ground Displacement, Proc. Japan-U.S. Workshop on Liquefaction, Large Ground Deformation and Their Effect on Lifeline Facilities, Nov. 16-19, Tokyo, Japan, Association for the Development of Earthquake Prediction, (Japan) and NCEER (U.S.), pp. 173-182.
Susuki H., and Tokimatsu, K. (2004). Effect of Pore Water Pressure Response Around Pile on p-y Relation During Liquefaction, Proc 11th Intl Conf on Soil Dyn and Earthq Eng, January 7-9, University of California, Berkeley, CA, Vol. 2, pp. 567-572.
Susuki H., Tokimatsu, K., Sato, M., and Abe, A. (2006) Factor Affecting Horizontal Subgrade Reaction of Piles During Soil Liquefaction and Lateral Spreading, ASCE Geotech Special Public No. 145 (Boulanger and Tokimatsu, eds.), Proc Workshop on Seismic Performance and Simulation of Pile Foundations in Liquefiable and Laterally Spreading Ground, March 16-18, 2005, University of California, Davis, CA, pp. 1-10.
Swan ,S.W., Flores, P.J., and Hooper, J.D. (1996). The Manzanillo Mexico Earthquake of October 9, 1995, NCEES Bulletin, The Quarterly Publication of NCEER, Vol. 10, No. 1, January.
128
-
Taboada, V.M. (1995). Centrifuge Modeling of Earthquake-Induced Lateral Spreading in Sand Using a Laminar Box, J Geotech Geoenviron Eng, Vol. 129, No. 10, pp. 879-889.
Tamura, S., and Tokimatsu, K. (2006) Seismic Earth Pressure Acting on Embedded Footing Based on Large-Scale Shaking Table Tests, ASCE Geotech Special Public No. 145 (Boulanger and Tokimatsu, eds.), Proc Workshop on Seismic Performance and Simulation of Pile Foundations in Liquefiable and Laterally Spreading Ground, March 16-18, 2005, University of California, Davis, CA, pp. 83-96.
TGC (1995). Geotechnical Response of Quay and Loading Areas in Puerto Manzanillo During October 1995 Earthquake, (in Spanish) Report TGC Geotecnia 95-1763-C, October, Mexico.
Tokimatsu, K. (1999). Performance of Pile Foundations in Laterally Spreading Soils, Proc 2nd Int Conf on Earthq Geotech Eng (P. Seco e Pinto, ed.), June 21-25, 1999, Lisbon, Portugal, Vol. 3, pp. 957-964.
Tokimatsu K., Mizuno, H., and Kakurai, M. (1996). Building Damage Associated with Geotechnical Problems, Soils and Foundations Special Issue on Geotechnical Aspects of the January 17 1995 Hyogoken-Nambu Earthquake, JGS, Special Vol. January, pp. 219-234.
Tokimatsu, K., H. Oh-Oka, Y. Shamoto, A. Nakazawa, and Y. Asaka. (1997). Failure and Deformation Modes of Piles Caused by Liquefaction-Induced Lateral Spreading in 1995 Hyogoken-Nambu Earthquake, Proc 3rd Kansai International Geotechnical Forum on Comparative Geotechnical Engineering (KIG-Forum '97), Kobe, January, Publ. by the Kansai Branch of the Japanese Geotechnical Society, pp. 239-248.
Tokimatsu, K., H. Oh-Oka, K. Satake, Y. Shamoto, and Y. Asaka, Y. (1998). Effects of Lateral Ground Movements on Failure Patterns of Piles in the 1995 Hyogoken-Nambu Earthquake, Proc ASCE Geotechnical Earthquake Engineering and Soil Dynamics III, Seattle, WA, August 3-6, 1998, Vol. 2, pp. 1175-1186
Tokimatsu, K., Suzuki, H., and Sato, M. (2004). Influence of Inertial and Kinematic Components on Pile Response during Earthquakes, Proc 11th Intl Conf on Soil Dyn and Earthq Eng, January 7-9, University of California, Berkeley, CA, Vol. 1, pp. 768-775.
Tokimatsu, K., Suzuki, H., and Sato, M. (2005). Effects of Inertial and Kinematic Interaction on Seismic Behavior of Pile with Embedded Foundation, J of Soil Dyn and Earthq Eng, Vol. 25, pp. 753-762.
Towhata, I., Sesov, V., Motamed, R., and Gonzalez, M. (2006). Model Tests on Lateral Earth Pressure on Large Group Pile Exerted by Horizontal Displacement of Liquefied Sandy Ground, Proc. 8th U.S. National Conf on Earthq Eng, April 18-22, 2006, San Francisco, CA, Paper No. 1227.
Ubilla, J. (2007). Physical Modeling of the Effects of Natural Hazards on Soil-Structure Interaction, Ph.D. Thesis, Rensselaer Polytechnic Institute, Troy, NY.
Uzuoka, R., Sento, N., Kazama, M., Zhang, F., Yashima, A., and Oka, F. (2007). Three-dimensional Numerical Simulation of Earthquake Damage to Group-Piles in a Liquefied Ground, J of Soil Dyn and Earthq Eng, Vol. 27, pp. 395-413.
Yao, S., Kobayashi, K., Yoshida, N., and Matsuo, H. (2004). Interactive Behavior of Soil-Pile-Superstructure System in Transient State to Liquefaction by Means of Large Shake Table Test, J of Soil Dyn and Earthq Eng, Vol. 24, pp. 397-409.
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Yasuda, F., A. Nanjoh, and K. Kosa. (1997). Investigation and Checking of Load Bearing Capacity of Damaged Piles, Proc. of the 3rd Kansai International Geotechnical Forum on Comparative Geotechnical Engineering (KIG-Forum '97), Kobe, January, Publ. by the Kansai Branch of the Japanese Geotechnical Society, pp. 249-257.
Yokoyama K., Tamura, K., and Matsuo, O. (1997). Design Methods of Bridge Foundations Against Soil Liquefaction and Liquefaction-Induced Ground Flow, Proc 2nd Italy-Japan Workshop on Seismic Design and Retrofit of Bridges, February 27-28, 1997, Rome, Italy, pp. 109-131.
Yoshida, N., and Hamada, M. (1991). Damage to Foundation Piles and Deformation Pattern of Ground Due Liquefaction-Induced Permanent Ground Deformations, Proc. 3rd Japan-U.S. Workshop on Earthquake Resistant Design of Lifeline Facilities and Countermeasures for Soil Liquefaction, NCEER, SUNY-Buffalo, Buffalo, NY, Tech. Rept. NCEER-91-0001 , pp. 147-161.
Yoshida, N., Watanabe, H., Yasuda, S., and Mora, S. (1992). Liquefaction-Induced Ground Failure and Related Damage to Structures During 1991 Telire-Limon, Costa Rica, Earthquake, Proc. 4th
Japan-U.S. Workshop on Earthquake Resistant Design of Lifeline Facilities and Countermeasures for Soil Liquefaction (Hamada and ORourke, eds.), NCEER, SUNY-Buffalo, Buffalo, NY, Tech. Rept. NCEER-92-0019, Vol. 1, pp. 37-52.
Yoshida, N., Towhata, I., Yasuda, S., and Kanatani, M. (2005). Discussion to An Alternative Mechanism of Pile Failure Deposits During Earthquakes by Bhattacharya et al., Geotechnique, Vol. 55, No. 3, pp. 259-263.
Youd, T.L. (1993), Liquefaction-Induced Damage to Bridges, Transportation Research Record, published by the TRB and the National Research Council, Washington, DC., No. 1411, pp. 35-41.
Youd, T.L., Rollins, K.M., Salazar, A.F., and Wallace, R.M. (1992). Bridge Damage Caused by Liquefaction During the 22 April 1991 Costa Rica Earthquake, Proc. 10th World Conference on Earthquake Engineering, July 19-24, Madrid, Spain, Vol. 1, pp 153-158.
Youd, T.L., Idriss, I.M., Andrus, R.D., Arango, I., Castro, G., Christian, J.T., Dobry, R., Finn, W.D.L., Harder Jr., L.F., Hynes, M.E., Ishihara, K., Koester, J.P., Liao, S.S.C., Marcuson III, W.F., Martin, G.R., Mitchell, J.K., Moriwaki, Y., Power, M.S., Robertson, P.K., Seed, R.B., and Stokoe II, K.H. (2001). Liquefaction Resistance of Soils: Summary Report from the 1996 NCEER and 1998 NCEER/NSF Workshops on Evaluation of Liquefaction Resistance of Soils, J Geotech Geoenviron Eng, Vol. 127, No. 10, pp. 817-833.
Youd, T.L., Idriss, I.M., Andrus, R.D., Arango, I., Castro, G., Christian, J.T., Dobry, R., Finn, W.D.L., Harder Jr., L.F., Hynes, M.E., Ishihara, K., Koester, J.P., Liao, S.S.C., Marcuson III, W.F., Martin, G.R., Mitchell, J.K., Moriwaki, Y., Power, M.S., Robertson, P.K., Seed, R.B., and Stokoe II, K.H. (2003). Closure to Liquefaction Resistance of Soils: Summary Report from the 1996 NCEER and 1998 NCEER/NSF Workshops on Evaluation of Liquefaction Resistance of Soils, J Geotech Geoenviron Eng, Vol. 129, No. 3, pp. 284-286.
Zeghal, M., and El Shamy, U. (2004). A Continuum-Discrete Hydromechanical Analysis of Granular Deposit Liquefaction, Int J Numer Anal Met Geomech, Vol. 28, No. 14, pp. 1361-1383.
Zeghal, M., and Oskay, C. (2003). A Local Identification Technique for Geotechnical and Geophysical Systems, Int J Numer Anal Meth Geomech, Vol. 27, No. 11, pp. 967-987.
Zeghal, M., Elgamal, A.W., Tang, H.T., and Stepp, J.C. (1995). Lotung Downhole Array. II: Evaluation of Soil Nonlinear Properties. J of Geotech Eng, Vol. 121, No. 4, pp. 363-378.
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WORKSHOP 1 Large scale facilities, geotechnical strong
motion arrays and experimental sites
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4th International Conference on Earthquake Geotechnical Engineering
June 25-28, 2007 Paper No. W1-1005
REFLECTIONS ON THE IMPORTANCE OF THE QUALITY OF THE INPUT MOTION IN SEISMIC CENTRIFUGE TESTS
Jean-Louis CHAZELAS 1, Gopal SP MADABHUSHI2
ABSTRACT
Dynamic centrifuge modelling is widely accepted as the experimental technique that can be used to understand complex behaviour of soil-structure systems subjected to earthquake loading. In Europe, the centrifuge facility at Schofield Centre in Cambridge has been active for more than 30 years in the area of dynamic centrifuge modelling. The earthquake loading is simulated on the Cambridge centrifuge using simple mechanical actuators that produce sinusoidal shaking. While such input motions are simple and helpful in deciphering certain aspects of soil behaviour particularly while assessing damaging effects of the earthquakes, the complex non-linear behaviour of soils requires more sophisticated earthquake actuators that can simulate multi-frequency nature of real earthquakes. Such a servo-hydraulic shaker has been established on the LCPC centrifuge in Nantes, similar to the shaker at C-Core centrifuge facility in St Johns, Canada. In this keynote paper, the importance of the quality of input motion is investigated. The difficulties in generating complex motion aboard centrifuges are discussed. Another aim of this paper is to discuss some of the exciting developments that are occurring in the modelling of earthquakes on centrifuges. The outline design of a 2-D (horizontal and vertical) shaker being developed at Cambridge is presented. Similarly creation of distributed testing facilities that are networked within UK under the UK-NEES project that is linked to US-NEES and other similar networks opens up a new era of collaborative testing in earthquake engineering.
Keywords: actuators, earthquakes, input motions, geotechnical engineering, centrifuge modelling
INTRODUCTION
Physical modeling in earthquake engineering with reduced scale experiments in the centrifuge is now widely considered as the established experimental technique of obtaining data in controlled conditions to help engineers and researchers to understand the mechanism involved in the response of soil structure systems to seismic loading. This experimental approach recreates the stress state in soils which is a fundamental condition to observe realistic soil behaviour. Of course, as any other experimental method it has its limitations, among which the most evident is the boundary effect due to the fact that the soil model mounted in the centrifuge is necessarily of limited dimensions. This is classically treated by using laminar or shear stack box which allow the natural deformation of a soil column. Another important limit is the ability to impose a realistic input at the base of the soil model. Earthquakes generate a complex sequence of vibrations that can lead to 3D displacements with a broad frequency content of very variable duration. Firstly, it is difficult to build a 3D shaking table in the
1 Senior Researcher, Laboratoire Central des Ponts et Chausses, Nantes, France, Email: [email protected] Reader in Geotechnical Engineering, Department of Engineering, University of Cambridge, Cambridge, UK, Email: [email protected]
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limited volume of the basket of a centrifuge. Secondly, it is difficult to generate independent time histories for each axis of shaking: it is of course simpler to generate harmonic inputs than to reproduce broad band records of real earthquakes. Note that these two problems apply as well to full scale shaking tables.
The purpose of this paper is to present recent and upcoming experimental facilities developed in Europe and discuss the effort that led to an improvement in the quality of the simulations. Establishing the quality of simulations essentially means to define and justify the choice of 1, 2 or 3D movements, the ability to simulate single or multi frequency inputs, and the quality of the resulting inputs in comparison with the target input. There is an on-going discussion amongst centrifuge modellers on the best type of input motions that may be used in dynamic centrifuge modelling. The input motion that has simple, sinusoidal tone bursts at different frequency will lend itself to easy analysis of the response the soil and the superstructure. This is used extensively at Cambridge on a wide range of boundary value problems in which the key mechanisms of failure are eloquently deciphered. This choice to some extent is independent of the actuators available with RPI centrifuge facility using sinusoidal inputs even though their servo-hydraulic shaker is capable of simulating realistic earthquakes. Similarly, use of a more realistic input motion from a previous earthquake such as Kobe motion or Northridge motion would be considered useful from the design of future structures point of view. Further, the role of multi-frequency input motion on the dynamic behaviour of soils is not fully understood. It is generally argued that for soil liquefaction problems use of simple input motions is sufficient. Recently, finite element analyses were carried out by Ghosh and Madabhushi (2003) and dynamic centrifuge modelling was carried out by Madabhushi, Ghosh and Kutter (2006) to investigate the role of type of input motions in the generation of excess pore pressures. These investigations revealed that the amount of excess pore pressure generated in loose, saturated sands may be not be effected by sinusoidal input motions or more realistic input motions. However, the amount of lateral spreading of sloping ground that can occur may be quite different if sinusoidal motions are used as the dilation spikes that occur during strong shaking cycles are more pronounced compared to a more realistic input motion with only a few strong cycles of shaking.
First attempts of centrifuge shaking tables were mechanical 1D harmonic devices based on leaf spring device (Morris, 1979), bumpy road tracks (Kutter, 1982) or cams systems (Suzuki et al., 1991, Kimura et al, 1998, ). Other technologies have been tested such as explosives (Zelikson et al., 1981), piezo-electric jacks (Arulanandan, 1982), electromagnetic motors (Fujii, 1994) - but the majority of the existing devices are now electro-hydraulic (Ketcham et al., 1988, Van Laak et al. 1994) because of the ability of electric servo-valves to accept complex driving functions and the command hydraulic jacks with a rich frequency content. Few 2 D devices have been developed either with two horizontal shaking directions or one horizontal and one vertical. The difficulty of avoiding uncontrolled frequency contents especially harmonics due to mechanical guidance and clearance in sine inputs and spurious movements especially yawing and rocking is largely increased from 1D to 2D. Note that these considerations apply as well to full scale shaking tables but with specific aspects due to the fact that the device is embarked in the basket of a rotating machine.
Among main issues in a shaker design are how to shake the biggest mass i.e. the largest model and how to control that the acceleration at the basis of the soil box with reduced spurious movements and reduced transmissions of vibration to the centrifuge. Till recently, the basic option was to use the basket of the centrifuge as the reaction mass for the shaking of the table. The heaviest payload was then dependent on the basket weight and the level of vibration tolerated by the centrifuge. The question of the spurious movements arises first from problems of symmetry in the case of a simple actuator, and from the coordination in the case of multiple actuator. The type of bearings is also of main importance in this design with two opposite schools; rigid guidance on rails and no guidance at all on oil bearings.
C-Core Laboratory in Newfoundland, Canada, and Laboratoire Central des Ponts et Chausses, France, have purchased a new concept 1D earthquake simulator (EQS) designed by ACTIDYN that overcome these two basic difficulties with a highly sophisticated set of technological solutions
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(Chazelas et al, 2006). On the other hand, Cambridge University has long operated 1D mechanical shakers (ref of the bumpy road, Madabhushi et al, 1998), and is now developing a new 2D simulator.
We propose here to present the different aspects of the performances achieved at LCPC's facility, to present the priorities assigned by Cambridge to its new design and then to open a debate on the interest of achieving such quality of input and control.
LABORATORY SPECIFICATIONS OF A HIGH QUALITY 1D SHAKING TABLE AT C-CORE AND LCPC
The specifications imposed to providers by C-Core and LCPC were very similar; they result from a bibliographical review of existing device giving an insight on what was possible and what have been the recent evolutions. Both Laboratories chose a 1D shaker, as very few 2D devices are now operational as there is still much work to realize in 1D modelling. The direction of the shaking, conventionally noted Y, was naturally fixed horizontal regarding the model in flight and parallel to the axis of rotation of the centrifuge regarding the fix natural repair in order to limit the Coriolis forces. The maximum g level of operation was fixed between 80 and 100 g as many models are achieved at 40, 50 or 80 g in the domain of foundations. Over 100 g, the models become very small and difficult to be instrumented. The most important specifications were the level of the horizontal acceleration a minimum of 0,4 g prototype scale this figure commonly admitted since Kobe 1995 earthquake. The control on the acceleration an not on the displacement was considered as compulsory in relation to the fact that the design of a reduced scale experiments in the centrifuge is controlled by the level of the centrifuge acceleration. C-Core called for proposal in 2001 and finally negotiated with Actidyn the performances recalled in table I. LCPC followed two year later and just increased certain values of the specifications (see table I). It must be emphasized that these specifications correspond to sine inputs; this inputs imply the highest power on the jacks shaking the table and the largest volume of hydraulic storage. These specifications included upper bounds for the spurious moments, expressed as a maximum 10% ratio between the X and Z acceleration on the table and the Y acceleration in the direction of the shaking. Note that these accelerations were to be recorded at the extremity of the table, the most severe position to evaluate these movements.
Table I : Specifications of C-Core and LCPC Earthquake simulators Specifications C- Core LCPC
Maximum centrifuge acceleration of operation (MAO) 80 g 80 g
Maximum payload 400 kg 400 kg
Maximum horizontal acceleration (Y direction) 0.5 MAO 0.5 MAO
Duration of full power sine shake 1 s 1 s
Maximum velocity 1m/s 1m/s
Maximum displacement 2.5 mm 5 mm
Bandwidth of operation in sine 20 200 Hz 20 250 Hz
Maximum spurious accelerations in X and Z direction recorded at the Y end of the shaking table
RMS X and RMS Z < 10% RMS Y
RMS X and RMS Z < 10% RMS Y
LCPC added a last category of specifications: the ability of the shaker to reproduce earthquakes with very specific signatures supposed to solicit differently the machine. Four records from reference earthquake were specified. They are recalled in table II with their respective selection criteria.
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TECHNOLOGICAL RESPONSE AND PERFORMANCES
In addition to the fulfilment of the above mentioned specifications, the main Actidyn's ambitions were to demonstrate its ability to isolate the centrifuge from the vibrations of the payload and to limit the spurious movements applied to the model. The technological choices have been detailed in [Perdriat et al, 2002] and [Hutin et al, 2004], and will only be described briefly here: - the main innovation was the concept of a permanent dynamic equilibrium between the payload on
its shaking table and a counterweight embarked together in the basket of the centrifuge. Actidyn was then able to increase largely the mass of the payload, provided the centrifuge was able to support thetotal mass. This last condition was easily fulfilled in both laboratories, - the second technological bet was to opt for oil bearings two superimposed, one for the counterweight on the basis of the shaker and one for the payload table on the counterweight (see fig.1). There is not any longitudinal guidance so as to avoid high frequencies due to micro shocks in mechanical clearance,
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Figure 1. Actityns EQS - Dynamic equilibrium payload counterweights
- another essential design option was to install one jack on each side of the shaking table between the payload table and the counterweight table. These two jacks and their servo-valves are operated through a multi-axis control system developed by Data Physics, Hutin et al., 2002.
In the simulation of the real earthquakes, specifications and technological limits of the machineconstraint the results: the control system computes the drive function sent to the servo-valves in a bandwidth of 20 to 400 Hz. Actidyn considered that the jacks would probably have a flat response till 200 or 250 Hz and then fixed the bandwidth controlled by the Data Physic software controller to 20 400 Hz. In the domain of broad band signals, the records were first filtered in the 20 - 350 Hz bandwidth because the power needed is much reduced as regard to sine tests. This means first that the prototype record has to be filtered in 0,5 - 8.75 Hz for 1/40th tests or 0.25 - 4.75 Hz for 1/80th test, for example before time scaling. It must then be pointed that the record from Kobe cannot be correctlyreproduced lower than 1/55th because its Fourier spectrum still contain much energy at 0,4 Hz. At higher reduction scales, the bandwidth of the system will accept such low frequency earthquakes.
The physical limits of the machines in terms of maximum accelerations, velocities and displacementsalso impose constraints : the maximum horizontal acceleration is limited to 0.5 the centrifugeacceleration, the velocity is limited to 1 m/s and the maximum displacement is limited to 5 mm. It is necessary to control, by a double integration process, that none of these limits will be overcome by the reference input. This leads to eventually apply a reduction factor on the filtered record as shown in thelast column of table II.
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With the combination of the specifications and the physical limits of the machine, any earthquake cannot be simulated without care but table II shows that a wide rage of characteristic earthquakes was theoretically possible to run. Figures 2 and 3 show the quality of the fitting of the model earthquake tothe reference record for two of these references. All these figures are expressed in the prototype 1gscale. The payload was in a first time a rigid concrete block of mass 400 kg. In the case of Mexico, thehigh frequency content corresponds to non controlled high frequencies (around 360 Hz) at the time of these tests. Since then, with a fine calibration of the accelerometers in the control loop, these spurious frequencies have been largely reduced. This is proved by the comparison of the Landers reference to records in the tree directions at the extremity of the shaking table supporting the payload (figure 5).This test was run at 40 g and the payload was a shear stack box with sand, for a total mass of 350 kg.
Table II: Real earthquake records selected as references in order to evaluate the performance of LCPCs earthquake simulator
Site Selection criteria Span Reduction ratio after filtering
Landers- Lucerne Valley Station Component N09E -28/06/1992
Short Strong amplitude in low frequencies and important velocity spike.
48 s 0 dB
Kobe DAI8-G - Component N43W - 17/01/95
Long span and high amplitudes of acceleration
120 s - 3 dB at 50 g - 4 dB at 80 g
Mexico - Sec. Com. YTransport StationComponent 090 19/09/85
Long span Rich spectrum in low frequencies
180 s 0 dB
Northridge Tarzana StationComponent 90 17/01/94
Very impulsive. Very high acceleration peaks
60 s - 8,5 dB at 50 g - 5.6 dB at 80 g
0.3
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Figure 4. Fourier Spectrum of Landers earthquake simulation with spurious accelerations
This last figure shows that the system is able to face a certain lack of equilibrium of the dynamicbalance as the counterweights are not of tunable mass.
The above-mentioned tests verified the ability of the device to simulate true 1D broadband earthquakes with different frequency content. Of course in the domain of sine inputs, known to bemuch more demanding for the machine, the main problem was to control the ability to carry out full power sine inputs under any centrifuge accelerations from 40 to 80 g and during 1 second (modelscale, which correspond respectively to 40 to 80 s at model scale). In brief, during the acceptance tests, we could carry out very pure sine inputs from 40 Hz up to 100 Hz in this range of centrifugeaccelerations and with the rigid 400 kg payload. Pure, here, meant with no spurious movements acceleration in the X (yawing) and Z (rocking) direction measured at the extremity of the shaking table greater than 15 % (we had specified 10%). As indicated earlier, last tests with a fine calibration of the accelerometers involved in the control loops largely widened this frequency range as we achieved tests at 40 g centrifuge, 18 g horizontal acceleration (or 0.45 g prototype scale) from 32 to 200 Hz with spurious moments in the X and Z direction limited to 10%.
Two other types of controls have been achieved during acceptance test: an analysis of the harmoniccontent of the sine inputs and a verification of the vibration of the basket and the arms of the centrifuge. The harmonic content had not been specified. The correction of the harmonic content is realized by the Data Physic control software through an iterative fitting process applied to a dummypayload. The most troublesome harmonics to be corrected were generally the third and the fifth and, at the end of the fitting process, appeared to be limited to less than 10 % of the main frequency
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component in the band 40 100 Hz. This should be improved with the recent corrections in thecontrol loops. Of course, when the sine input will be over 130 Hz, correcting the third harmonic will be impossible due to the 400 Hz limit of the controller.
The control of the vibration of the basket is not yet completely checked: it has been only conducted at40gs due to aging of the centrifuge itself. The isolation was determined at different frequencies with sinusoidal motion. It was calculated as the ratio of the acceleration measured on the shaking table to the one measured at the basket floor or on the arms. It is to be compared to the inertial isolation ratio, the ratio of the basket and simulator mass to the payload mass. The inertial isolation ratio is 6.5 while from 40 to 100 Hz the real isolation is from 30 to 60, that is to say an improvement of a factor 5 to 9. At lower frequencies the isolation improvement is reduced to 3 and at higher frequencies, it vanished progressively but these tests should be renewed next with the corrections introduced in thecontrol loops.
Globally speaking, the earthquake simulator at LCPC produces earthquakes with a very good fitting to the reference signal, as well sinusoidal motion of up to 0.5 g (prototype scale) as a wide range of broad band real records at 40 and 50 g centrifuge in the bandwidth 40 200 Hz for sinusoidal motion and 0 350 Hz for broad band record. At higher level of centrifuge acceleration up to 80 gc - the bandwidth of acceptable response has been tentatively controlled to be narrower up to 100 Hz - but should be once more controlled with recent improvements. Good fitting means limited spuriousmovements yawing and rocking accelerations at the extremity of the table less that 10 to 15% - and superior harmonics for sine inputs limited to 10% in amplitude.
EARTHQUAKE GEOTECHNICAL ENGINEERING RESEARCH AT CAMBRIDGE UNIVERSITY
Current Facilities: The success of earthquake geotechnical engineering at Cambridge depended to a large extent on the simple mechanical actuators that have been used for more than 30 years. The current earthquakeactuator that relies on Stored Angular Momentum (SAM) to deliver powerful earthquakes at high gravities was developed and is in operation for 12 years, Madabhushi et al (1998). In Fig.5 the front view of the SAM actuator while in Fig.6 a view of the SAM actuator loaded onto the end of the 10mdiameter Turner Beam centrifuge is presented. The model seen in Fig.6 was from an investigation carried out by Haigh and Madabhushi (2002), on lateral spreading of liquefied ground past square and circular piles.
Figure 5. A view of SAM earthquake actuator at Cambridge
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The SAM earthquake actuator is a mechanical device which stores the large amount of energy required for the model earthquake event in a set of flywheels. At the desired moment this energy is transferred to the soil model via a reciprocating rod and a fast acting clutch. When the clutch is closed through a high pressure system to start the earthquake, the clutch grabs the reciprocating rod and shakes with an amplitude of 2.5 mm. This is transferred to the soil model via a bell crank mechanism. The levering distance can be adjusted to vary the strength of the earthquake. The duration of the earthquake can be changed by determining the duration for which the clutch stays on. Earthquakes at different frequencytone bursts can be obtained by selecting the angular frequency of the flywheels.
Recent modifications to the SAM actuator were carried out to further enhance its capabilities and to improve the performance envelope. Early earthquakes using this device were non-symmetric as the clutch migrated downwards to an end stop once the centrifugal acceleration was applied. This meantthat at the start of the earthquake the clutch body was hitting the end stop if it grabbed the reciprocating rod during its downward motion. This problem has been rectified by incorporating a pneumatic actuator that centralises the clutch prior to every earthquake. Logic controls automaticallyturn the air to the pneumatic actuator off once the earthquake is fired and the clutch starts to movewith the reciprocating rod.
In its original conception the SAM actuator was mounted onto the end of the beam centrifuge and shook a package on the special swing, reminiscent of the Bumpy Road actuator, Kutter (1982). However this arrangement was modified and a self-contained swing platform was developed that could house the SAM actuator as shown in Fig. 5 following a research grant (No:GR/L90415/01) fromEPSRC, UK. This has transformed the usage of the SAM actuator and since 1994 nearly PhD students utilised this facility and several industrial, EPSRC and EU projects were successfully completed using this actuator.
Figure 6. A view of SAM earthquake actuator loaded onto the end of the beam centrifuge (Model seen is that of lateral spreading of soil past square and circular piles,
Haigh and Madabhushi (2002))
The technical specifications of the SAM actuator are listed in Table III. In its normal operational modethe SAM actuator is used to deliver strong shaking to model packages either at particular but different tone bursts that could recreate damaging cycles felt by the structure during an earthquake loading or toapply a swept sine wave motion to detect the frequency response of the soil-structure system.
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Table III: Specifications of the SAM actuator Parameter ValueMaximum g-level of operation 100 g
56 m (L) 25 m (B) 22 m (H) Dimension of the soil models80 m (L) 25 m (B) 40 m (H)
Earthquake strength of choice Upto 0.4g of bed rock acceleration Earthquake duration of choice From 0 s to 150 s
From 0.5 Hz to 5 Hz Earthquake frequency of choice Swept sine wave capability
Note: All parameters above are in prototype scale
As mentioned earlier the SAM actuator was used in the investigation of several boundary value problems. As an example of the input motions generated by the SAM actuator the following investigation of liquefaction induced lateral spreading problem is presented. The dynamic behaviourof the slope was studied using miniature instrumentation for the measurement of pore-pressures and accelerations throughout the slope. Analysis of these signals has revealed interesting details about theresponse of these slopes to earthquake loading. The accelerometer time-histories in Fig.7 show themeasured base (ACC 9082), mid layer acceleration (ACC 8076) and surface accelerations (ACC 8025)in one of the models. It can be seen that whilst the base motion is approximately constant from cycleto cycle, the surface response late in the earthquake shows alternate cycles having profoundly different behaviour.
Figure 7. Acceleration time-histories
This shows itself as an amplified frequency component at half of the fundamental earthquake frequency upon study of FFTs. Measurement of the phase lag of acceleration between base andsurface of the models, as could be achieved from the time-histories shown in Fig.8, allows estimates ofthe shear wave velocity to be made at different times during the earthquake. From this data it can be shown that as the soil liquefies and softens, the shear wave velocity falls to such a point that the natural frequency of the soil column becomes approximately 25 Hz, half that of the earthquakeexcitation. It is thus postulated that the soil column is resonating at this natural frequency, hencegiving the behaviour described above.
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Figure 8. Upward propagation of S wave It is also interesting to note the dilative response of the soil slope. All of the PPTs present in the model show significant dilative behaviour occurring with the generation of a suction-spike once per cycle. Examining the timing of these spikes with respect to depth illustrates that this suction pulse propagates vertically from the base of the model to the surface at the shear wave velocity. This behaviour is illustrated in Fig.9. It is postulated that this is due to the dynamic shear stress applied bythe wave, superimposed on the initial static shear stress causing the soil stress path to cross thecharacteristic state threshold and hence the soil to dilate. This pore-pressure behaviour will cause a slip-stick motion of the soil down the slope, with velocity and displacement being accumulated while the base is accelerating upslope and then locking up on the other half-cycle when dilation occurs. As described earlier using a sinusoidal input motion may lead to an under-estimate of the amount oflateral spreading of sloping ground that can occur as strong cycles of shaking are applied throughout the model earthquake, making the liquefied soil to dilate in each half cycle and hence stopping the lateral displacement of the ground. If a more realistic earthquake motion is applied then the ground liquefies during one or two strong cycles applied and stays liquefied during the smaller cycles that follow allowing the ground to suffer much larger lateral displacement. This is one example where typeof input motion can have a bearing on the output from the centrifuge test.
Figure 9. Upward propagation of the suction spike
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Future Developments:
At Cambridge University, preliminary design of a new 2-D earthquake actuator has been recentlycompleted. This actuator, when fabricated will be able to shake the soil models both horizontally and vertically akin to the 2-D actuator recently established at UC Davis in the USA. The vertical groundaccelerations can play an important role in the ultimate performance of a structure. Recent earthquakeshave yielded many recordings of vertical accelerations which are quite large (in some cases up to 0.8g to 1.0g). Current design codes only allow for a fraction of these as vertical accelerations. Also the combination of vertical shaking followed by strong horizontal shaking can lead to unexpected and interesting failure mechanisms in a wide range of civil engineering structures. With this in view the Cambridge 2-D earthquake actuator project has been initiated and is currently at an early stage. Aschematic diagram of the 2-D earthquake actuator assembly is presented in Fig.10 below. A Pro-Engineer CAD drawing is presented in Fig.11. The design of this 2-D actuator for the Cambridgecentrifuge is quite demanding as the payload capacity of the Turner beam centrifuge is limited to 1tonne. In addition there are severe space constraints. Further, the Turner beam centrifuge is used extensively for non-earthquake testing which means that the 2-D earthquake actuator needs to be loaded and unloaded on and off the centrifuge quite frequently. These bring in additional complexitiessuch as breaks in high pressure hydraulic lines, contamination of the hydraulic fluid etc. Despite these difficulties the design of this 2-D actuator is progressing well and with suitable funding should be available for use in a few years time. This would become the only 2-D earthquake actuator to serve the European Community.
The specifications of the 2-D shaker were drawn taking to consideration the special requirements of the Turner beam centrifuge. Unlike the LCPC shaker the entire centrifuge is used as the reaction massas the swing platform on which the 2-D shaker is mounted is locked onto the centrifuge when the centrifuge is speeded up beyond 10gs. Also the use of the 2-D shaker is expected to complement the SAM earthquake actuator that can operate at high gravities and deliver powerful sinusoidal earthquakes. The 2-D shaker will be used at relatively lower g levels but with more realistic earthquake input motions in horizontal and vertical directions.
Figure 10. Schematic view of the 2-D actuator assembly
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Table IV: Preliminary design specifications of the 2-D earthquake actuator Parameter ValueMaximum g-level of operation 50 g ~ 80 g
56 m (L) 25 m (B) 22 m (H) Dimension of the soil models80 m (L) 25 m (B) 40 m (H) Up to 0.8gEarthquake strength of choice Horizontal direction
Vertical direction Up to 0.6g Earthquake duration of choice From 0 s to 150 s Earthquake frequency of choice From 0.5 Hz to 5 Hz
Note: All parameters above are in prototype scale
There is a good collaboration between Cambridge group and the geotechnical centrifuge modellers at UC Davis through the EPSRC funded UK-NEES project and at LCPC, Nantes through the funding provided by British Council in France. The lessons learnt on the quality of input motions from servo-hydraulic shakers at Davis and Nantes will be extremely valuable in the development of the 2-Dshaker at Cambridge.
UK NEES Project: Another exciting development in the field of earthquake engineering research is the NEES project in the USA that established the concept of distributed testing at geographically distributed sites. This concept is extremely useful for Europe given the expertise in earthquake engineering in Europe and the geographical distances between the centres of excellence. Having distributed experimentalfacilities that are linked to a dedicated network will enable research workers in the whole of Europe to not only access the experimental data but to actually have tele-observation and tele-participation capabilities. The USA-NEES project has been well set up and a similar network in Europe benefitsfrom the technological advances already achieved in the USA. For example, network protocols fordata sharing and data archiving are already available.
Figure 11. Schematic view of the 2-D actuator
To complement the US-NEES, EPSRC funded a research project to develop a UK-NEES networkamong Cambridge, Oxford and Bristol universities. This project is at an early stage and a furtheropportunity arose to collaborate with NZ-NEES program in New Zealand. In Fig.12 a snapshot of one of the meetings is presented which shows the teams from Cambridge, Oxford, Bristol and Auckl