Parametric Studies of Source and Site Effects for the Generation of

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Parametric Studies of Source and Site Effects for the Generation of
Workshop
Workshop on
on seismic
seismic input
input motions,
motions, incorporating
incorporating recent
recent geological
geological studies
studies
Tsukuba,
Tsukuba, Japan
Japan 15
15 November
November 2004
2004
Parametric
Parametric Studies
Studies of
of Source
Source and
and Site
Site
Effects
Effects for
for the
the Generation
Generation of
of
Groundshaking
Groundshaking Scenarios
Scenarios
Fabio
Fabio ROMANELLI
ROMANELLI
Dept.
Dept.Earth
EarthSciences
Sciences
Università
Universitàdegli
deglistudi
studididiTrieste
Trieste
Franco
Franco VACCARI
VACCARI
Giuliano
Giuliano F.
F. PANZA
PANZA
SAND
SAND GROUP
GROUP of
ofthe
theabdus
abdus salam
salam
international
centre
for
theoretical
international centre for theoreticalphysics
physics
Outline
Introduction
Some problems in SHA (source-site effects)
P-B design input
Realistic definition of seismic input
Example Case and parametric studies
Focal mechanism
Site effects
Directivity
Conclusions
PSHA
PSHA &
& DSHA
DSHA dualism
dualism
PSHA
Waveform
modelling
Accounts for all
potentially damaging
earthquakes in a
region
Focus on selected
controlling
earthquakes
Single parameter
Complete time series
Deeply rooted in
engineering practice
(e.g. buliding codes)
Dynamic analyses of
critical facilities
Disaggregation,
recursive analysis
Introduction
Study of attenuation
relationships
PSHA
DSHA
PEER
Report
Introduction
In many applications a recursive analysis, where deterministic
interpretations are triggered by probabilistic results and vice
versa, will give the greatest insight and allow the most informed
decisions to be made.
Important
Important issues
issues in
in SRE
SRE
Modified from: Field et al., 2000
Near surface effects: impedance contrast, velocity
geological maps, v30, vl/4, ??
Basin effects
Basin-edge induced waves
Subsurface focusing
The convolutional model is ultimately artificial
(e.g. fault rupturing along the edge of a deep basin)
Problems in SHA-Site effects
SRE
SRE and
and SHA
SHA
Amplification patterns may vary greatly among
the earthquake scenarios, considering different source
locations (and rupture ...)
SCEC
Phase 3
Report
The convolutional model is ultimately artificial
(e.g. fault rupturing along the edge of a deep basin)
Problems in SHA-Site effects
SRE
SRE and
and SHA
SHA
In SHA the site effect should be defined as the
average behavior, relative to other sites, given all
potentially damaging earthquakes
This produces an intrinsic variability with respect to
different earthquake locations, that cannot exceed
the difference between sites
Site characterization:
which velocity?
use of basin depth effect? Is it a proxy for
backazimuth distance?
how to reduce aleatoric uncertainty?
Problems in SHA-Site effects
Seismic
Seismic Input
Input
A proper definition of the seismic input for PBD at a
given site can be done following two main approaches:
The first approach is based on
the analysis of the available
strong motion databases,
collected by existing seismic
networks, and on the grouping
of those accelerograms that
contain similar source, path and
site effects
The second approach is based
on modelling techniques,
developed from the knowledge
of the seismic source process
and of the propagation of
seismic waves, that can
realistically simulate the
ground motion
The
The ideal
ideal procedure
procedure is
is to
to follow
follow the
the two
two
complementary
complementary ways,
ways, in
in order
order to
to validate
validate the
the
numerical
numerical modelling
modelling with
with the
the available
available recordings
recordings
Definition of seismic input
Validation
Validation
The ideal procedure is to follow the two complementary
ways, in order to validate the numerical modelling with the
available recordings (e.g. Decanini et al., 1999; Panza et al.,
2000a,b,c).
Validation and calibration should consider intensity
measures (PGA, PGV, PGD, SA, etc.) as well as other
characteristics (e.g. duration).
The misfits can be due to variability in the physical (e.g.
point-source) and/or the parameters models adopted.
Definition of seismic input
Prediction
Prediction
The result of a simulation procedure should be a set of
intensity estimates, as the result of a parametric study
for different “events” and/or for different model
parameters
The modeling variability, estimated through validation,
can be associated to “models” or “parameters”
Epistemic
Modeling
(point source,
1D-2D-3D)
Parametric
(incomplete data)
Aleatory
Modeling
(scattering, rupture)
Parametric
(rupture)
e.g. Stewart et al., 2001
Definition of seismic input
Time
Time histories
histories selection
selection
They
They are
are used
used to
to extract
extract aa measure,
measure, representing
representing
adequately:
adequately:
Magnitude,
Magnitude, distance
distance
Source
Source characteristics
characteristics (fling,
(fling, directivity)
directivity)
Path
Path effects
effects (attenuation,
(attenuation, regional
regional heterogeneities)
heterogeneities)
Site
Site effects
effects (amplification,
(amplification, duration)
duration)
The
The groundshaking
groundshaking scenarios
scenarios have
have to
to be
be based
based
on
on significant
significant ground
ground motion
motion parameters
parameters
(e.g.
(e.g. velocity
velocity and
and displacement).
displacement).
Definition of seismic input
Parameters
Parameters extraction
extraction
Particularly, in the case of forward rupture directivity most
of the energy arrives in a single large pulse of motion which
may give rise to particularly severe ground motion at sites
toward which the fracture propagation progresses.
it involves the transmission of large energy amounts to
the structures in a very short time.
These shaking descriptors, strictly linked with energy
demands, are relevant (even more than acceleration),
especially when dealing with seismic isolation and passive
energy dissipation in buildings.
Performance-Based Design
VAB
VAB Project
Project (EC)
(EC)
ADVANCED
ADVANCED METHODS
METHODS FOR
FOR ASSESSING
ASSESSING
THE
THE SEISMIC
SEISMIC VULNERABILITY
VULNERABILITY
OF
OF EXISTING
EXISTING MOTORWAY
MOTORWAY BRIDGES
BRIDGES
ARSENAL RESEARCH, Vienna, Austria; ISMES S.P.A,. Bergamo, Italy;
ICTP, Trieste, Italy; UPORTO, Porto, Portugal; CIMNE, Barcelona, Spain;
SETRA, Bagneaux, France; JRC-ISPRA, EU.
Effects on bridge seismic response of
asynchronous motion at the base of bridge piers
Examples
Examples from
from EU
EU project
project
Databank of geological, geophysical and seismotectonic data
SEISMIC SOURCES
1) Database of focal mechanism
9
10
11
12
13
14
15
16
17
SEM63
SEM64_2
49
49
48
48
WARTH
SEM64_1
47
47
SEE72
NEU72
46
46
9
10
11
12
13
14
15
16
17
2) Parametric study on focal mechanism:
strike
dip
rake
depth
Maximum Credible Earthquake
Maximum Design Earthquake
Case study examples
Maximum
Historical
Earthquake
Initial LHM - Warth bridge - model
S-wave velocities
Case study examples
120
220
290
(m/s) 1100
1800
1900
Bedrock
Initial
Initial regional
regional model
model
EUR
EUR II data
data set
set
Density (g/cm3)
Distance (km)
300
0
0
Depth (km)
50
Depth (km)
100
150
200
250
300
2
3
4
5
6
7
8
9 10 1
2
3
4
Attenuation
5 0
500
1000
0
10
10
20
20
30
30
40
40
50
50
60
60
70
70
80
80
90
90
100
350
1
2
3
4
5
6
7
8
Velocity (km/s)
400
1.0
2.5
3.0
3.5
4.0
4.2
4.5
S-wave velocity (km/s)
Definition of str. models
4.8
5.0
5.5
1500
0
9 10 1
2
3
Density
4
(g/cm3)
5 0
500
1000
Attenuation
100
1500
Depth (km)
Velocity (km/s)
1
Hybrid
Hybrid method:
method: MS-FD
MS-FD
Distance from the source
Free surface
A
Depth
Source
Reference layered model
Artificial boundaries, limiting
the FD grid.
A
Zone of high attenuation, where
Q is decreasing linearly toward
the artificial boundary.
Local heterogeneous model
Definition of seismic input
Adjacent grid lines, where the wave
field is introduced into the FD grid. The
incoming wave field is computed with
the mode summation technique. The
two grid lines are transparent for
backscattered waves (Alterman and
Karal, 1968).
Site
Different source-section configurations
S3
S2
S1
Bedrock
model
S3
Mw = 6.0
Distance = 50 km
Definition of seismic input
S1
Strike = 190˚
Dip = 70˚
Rake = 324˚
Depth = 5 km
Mw = 5.5
Distance = 8.7 km
S2
Mw = 5.5
Distance = reverse
COMPUTATION
COMPUTATION OF
OF SEISMIC
SEISMIC INPUT
INPUT
PRELIMINARY COMPUTATION
INITIAL source and structural models
3 components of motion
Displacement, velocity, acceleration
FINAL COMPUTATION
FINAL source and structural models
3 components of motion
Displacement, velocity, acceleration
SEISMIC INPUT
DIFFERENTIAL
MOTION
SITE RESPONSE
1) 1D 10 Hz Parametric study
2) 2D 8Hz
1) time domain
2) spectral domain
1) Fourier spectral ratios
2) Response spectral ratios
Case study examples
PARAMETRIC
PARAMETRIC STUDY
STUDY -- Fp
Fp towards
towards MCE
MCE
All the focal mechanism parameters of the original source model have been
varied in order to find the combination producing the maximum amplitude
of the various ground motion components.
0°
0°
330°
20
30°
300°
330°
30°
300°
60°
60°
source depth (km)
1000
900
270°
90°
90° 270°
1) Strike
150 100 50 (Depth=5km)
0
10 8 6 4 2 0
15 250 200angle
800
700
120°
240°
120°
2) Rake240°angle
600
210°
150°
210°
150°
10 a)
180°
180°
b)
3) Strike-Rake
angles variation
(Dip=45°) 500
0°
400
330°
30°
300
4) Strike-Rake angles
variation (Dip=70°)
300°
60°
5
200
5) Strike-Rake angles variation (Dip=90°) 100
270°
90°
1 0.8 0.6 0.4 0.2 0
6) Depth-Distance
variation
0
5
(Strike=60°,
240°
10
15
210°
distance
(km) 150°
Dip=70°,Rake=0,
c)
180°
0
120°
20
90°)
The computations of synthetic seismograms (displacements, velocities and
accelerations for the radial, transverse and vertical components) have
been carried out with cut-off frequency 10 Hz.
Parametric study 1 - FP
cm/s**2
Tranverse
Tranverse accelerograms
accelerograms M=5.5,
M=5.5, d=6km
d=6km
400
200
0
-200
-400
0
1
2
200
250
260
290
300
400
500
1000
1100
1900
Bedrock
Parametric study 1 - FP
3
4
5
6
time (s)
7
8
9
10
Tranverse
Tranverse acceleration
acceleration spectra
spectra
300
first_2
Acceleration FA (cm/s)
100
0
1
2
3
4 5 6 7
frequency (Hz)
8
9 10
300
prev_5
200
first_5
100
prev_7
200
100
0
0
0
fsp_3
first_7
1
2
3
4 5 6 7
frequency (Hz)
8
0
9 10
1
2
3
4 5 6 7
frequency (Hz)
8
9 10
prev_3
200
300
first_3
fsp_8
300
0
0
1
2
3
4 5 6 7
frequency (Hz)
8
9 10
300
prev_4
200
fsp_6
first_4
Acceleration FA (cm/s)
100
Acceleration FA (cm/s)
fsp_4
Acceleration FA (cm/s)
0
fsp_7
fsp_5
Acceleration FA (cm/s)
200
300
300
prev_2
Acceleration FA (cm/s)
Acceleration FA (cm/s)
fsp_2
100
prev_6
200
first_6
1
2
3
4 5 6 7
frequency (Hz)
8
0
0
Parametric study 1 - FP
100
0
9 10
0
200
250
260
290
300
400
500
1000
1100
1900
Bedrock
first_8
200
100
0
0
prev_8
1
2
3
4 5 6 7
frequency (Hz)
8
9 10
1
2
3
4 5 6 7
frequency (Hz)
8
9 10
PARAMETRIC
PARAMETRIC STUDY
STUDY 22 -- Fp
Fp towards
towards 1Hz
1Hz
Another parametric study has been performed in order to find a seismic sourceWarth site configuration providing a set of signals whose seismic energy is
concentrated around 1 Hz, frequency that corresponds approximately to that of
the fundamental transverse mode of oscillation of the bridge.
20
1.2
500
1.15
450
16
1.1
400
14
1.05
350
1
300
0.95
250
0.9
200
0.85
150
0.8
100
focal depth (km)
18
12
10
8
6
4
0
10
20
30
50
40
60
source-site distance (km)
70
80
90
100
The
The results
results show
show that,
that, in
in order
order to
to reach
reach aa relevant
relevant value
value of
of PGA
PGA (e.g.
(e.g. greater
greater
than
than 0.1g)
0.1g) in
in the
the desired
desired period
period range
range (i.e.
(i.e. 0.8-1.2
0.8-1.2 s),
s), an
an alternative
alternative and
and suitable
suitable
configuration
configuration is
is aa source
source
12
12 km
km deep
deep at
at an
an epicentral
epicentral distance
distance of
of 30
30 km.
km.
Parametric
Parametric study
study 22 -- FS
FS &
& RSR
RSR
1
70
70
2
60
60
3
50
50
4
40
40
5
Acceleration FA (cm/s)
Acceleration FA (cm/s)
80
80
6
30
30
7
20
20
0
0
2
3
4
5
6
7
8
8
bedrock
bedrock
10
10
0
1
0
1
1
2
2
3
3
4
5
6
4
5
6
frequency (Hz)
frequency (Hz)
7
7
8
8
9
9
10
10
8.0
8.0
3.5
3.5
7.0
7.0
3.0
3.0
6.0
6.0
2.5
2.5
4.0
4.0
2.0
2.0
Frequency (Hz)
Frequency (Hz)
5.0
5.0
3.0
3.0
1.5
1.5
2.0
2.0
1.0
1.0
1.0
1.0
0.0
0.0
30.0
30.0
0.5
0.5
30.1
30.1
30.2
30.2
30.3
30.4
30.3
30.4
Distance (km)
Distance (km)
30.5
30.5
30.6
30.6
30.7
30.7
The
The results
results show
show that,
that, the
the local
local structure
structure beneath
beneath the
the Warth
Warth bridge
bridge greatly
greatly amplifies
amplifies the
the
frequency
frequency components
components between
between 33 and
and 77 Hz,
Hz, i.e.
i.e. aa frequency
frequency range
range not
not corresponding
corresponding to
to the
the
fundamental
fundamental transverse
transverse mode
mode of
of oscillation
oscillation of
of the
the bridge
bridge (about
(about 0.8
0.8 Hz)
Hz)
Parametric study 2 - DD
Parametric
Parametric study
study 33 -- LMp
LMp towards
towards 1Hz
1Hz
a)
Local
geotechnical
models of
Warth bridge
section obtained
lowering
successively the
S-wave
velocities of the
uppermost units
b)
c)
100
125
Parametric study 3 - LM
130
140
150
S wave velocities (m/s)
200
250
1000
Bedrock
1900
1100
400
400
SS1a_1
SS1a_1
SS1a_2
SS1a_2
350
350
AccelerationFA
FA(cm/s)
(cm/s)
Acceleration
300
300
Parametric
Parametric study
study 33
FAS
FAS
SS1a_3
SS1a_3
SS1a_4
SS1a_4
250
250
SS1a_5
SS1a_5
SS1a_6
SS1a_6
200
200
150
150
SS1a_7
SS1a_7
SS1a_8
SS1a_8
100
100
50
50
11
22
33
44
55
66
frequency
(Hz)
frequency (Hz)
77
88
99
10
10
SS1b_1
SS1b_1
SS1b_2
SS1b_2
350
350
AccelerationFA
FA(cm/s)
(cm/s)
Acceleration
300
300
300
300
150
150
200
200
50
50
00
00
400
400
00
00
400
400
33
44
55
66
frequency
frequency(Hz)
(Hz)
77
88
10
10
SS1c_1
SS1c_1
SS1c_2
SS1c_2
350
350
AccelerationFA
FA(cm/s)
(cm/s)
Acceleration
300
300
200
200
50
50
11
22
Case study examples
33
44
55
66
frequency
(Hz)
frequency (Hz)
77
88
99
33
44
55
66
frequency
(Hz)
frequency (Hz)
77
10
10
SS2c_5
SS2c_5
SS2c_6
SS2c_6
150
150
SS2c_7
SS2c_7
SS2c_8
SS2c_8
100
100
50
50
00
00
99
SS2c_3
SS2c_3
SS2c_4
SS2c_4
200
200
10
10
88
SS2c_1
SS2c_1
SS2c_2
SS2c_2
250
250
SS1c_7
SS1c_7
SS1c_8
SS1c_8
100
100
22
300
300
SS1c_5
SS1c_5
SS1c_6
SS1c_6
150
150
11
350
350
SS1c_3
SS1c_3
SS1c_4
SS1c_4
250
250
00
00
99
AccelerationFA
FA(cm/s)
(cm/s)
Acceleration
22
SS2b_7
SS2b_7
SS2b_8
SS2b_8
100
100
50
50
11
SS2b_5
SS2b_5
SS2b_6
SS2b_6
150
150
SS1b_7
SS1b_7
SS1b_8
SS1b_8
100
100
SS2b_3
SS2b_3
SS2b_4
SS2b_4
250
250
SS1b_5
SS1b_5
SS1b_6
SS1b_6
200
200
SS2b_1
SS2b_1
SS2b_2
SS2b_2
350
350
SS1b_3
SS1b_3
SS1b_4
SS1b_4
250
250
400
400
AccelerationFA
FA(cm/s)
(cm/s)
Acceleration
00
00
400
400
11
22
33
44
55
66
frequency
(Hz)
frequency (Hz)
77
88
99
10
10
8.0
8.0
7.0
7.0
7.0
7.0
6.0
6.0
6.0
6.0
5.0
5.0
Frequency (Hz)
Frequency (Hz)
5.0
5.0
4.0
4.0
4.0
4.0
3.0
3.0
3.0
3.0
2.0
2.0
2.0
2.0
1.0
1.0
1.0
1.0
0.0
0.0
8.6
8.0 8.6
8.0
Parametric
Parametric study
study 33 RSR
RSR
0.0
0.0
8.7
8.7
8.8
8.8
8.9
9.0
9.1
8.9
9.0
9.1
Distance (km)
Distance (km)
9.2
9.2
9.3
9.3
9.4
9.4
8.0
8.0
7.0
7.0
6.0
6.0
6.0
6.0
5.0
5.0
5.0
5.0
Frequency (Hz)
Frequency (Hz)
Frequency (Hz)
Frequency (Hz)
7.0
7.0
4.0
4.0
4.0
4.0
3.0
3.0
3.0
3.0
2.0
2.0
2.0
2.0
1.0
1.0
1.0
1.0
0.0
0.0
8.6
8.0 8.6
8.0
8.7
8.7
8.8
8.8
8.9
9.0
9.1
8.9
9.0
9.1
Distance (km)
Distance (km)
9.2
9.2
9.3
9.3
9.4
9.4
0.0
0.0
30.0
30.0
8.0
8.0
7.0
7.0
6.0
6.0
6.0
6.0
5.0
5.0
5.0
5.0
4.0
4.0
30.3
30.4
30.3
30.4
Distance (km)
Distance (km)
30.5
30.5
30.6
30.6
30.7
30.7
30.1
30.1
30.2
30.2
30.3
30.4
30.3
30.4
Distance (km)
Distance (km)
30.5
30.5
30.6
30.6
30.7
30.7
4.0
4.0
3.0
3.0
3.0
3.0
2.0
2.0
2.0
2.0
1.0
1.0
1.0
1.0
0.0
0.0
8.6
8.6
30.2
30.2
Frequency (Hz)
Frequency (Hz)
Frequency (Hz)
Frequency (Hz)
7.0
7.0
30.1
30.1
8.7
8.7
8.8
8.8
Case study examples
8.9
9.0
9.1
8.9
9.0
9.1
Distance (km)
Distance (km)
9.2
9.2
9.3
9.3
9.4
9.4
0.0
0.0
30.0
30.0
Synthetic
Synthetic accelerations
accelerations and
and diffograms
diffograms
Case study examples
400
400
SS2c_1
SS2c_1
SS2c_2
SS2c_2
350
350
AccelerationFA
FA(cm/s)
(cm/s)
Acceleration
300
300
200
200
SS2c_5
SS2c_5
SS2c_6
SS2c_6
150
150
SS2c_7
SS2c_7
SS2c_8
SS2c_8
100
100
50
50
11
22
33
44
55
66
frequency
(Hz)
frequency (Hz)
77
99
10
10
p_2
p_2
350
350
AmplitudeFourier
FourierSpectra
Spectra(cm/s)
(cm/s)
Amplitude
88
p_4
p_4
250
250
p_5
p_5
44
66
f_2
f_2
350
350
AmplitudeFourier
FourierSpectra
Spectra(cm/s)
(cm/s)
Amplitude
55
f_4
f_4
250
250
f_5
f_5
44
66
f_3_1D
f_3_1D
f_4_1D
f_4_1D
f_5_1D
f_5_1D
f_6_1D
f_6_1D
f_7_1D
f_7_1D
150
150
f_8
f_8
55
f_2_1D
f_2_1D
200
200
f_8_1D
f_8_1D
100
100
100
100
50
50
00
00
400
400
33
frequency
frequency(Hz)
(Hz)
250
250
f_7
f_7
150
150
22
300
300
f_6
f_6
200
200
11
350
350
f_3
f_3
300
300
p_8_1D
p_8_1D
50
50
00
00
AmplitudeFourier
FourierSpectra
Spectra(cm/s)
(cm/s)
Amplitude
33
frequency
frequency(Hz)
(Hz)
p_7_1D
p_7_1D
100
100
50
50
22
p_6_1D
p_6_1D
150
150
p_8
p_8
11
p_5_1D
p_5_1D
200
200
100
100
00
00
400
400
p_4_1D
p_4_1D
250
250
p_7
p_7
150
150
p_3_1D
p_3_1D
300
300
p_6
p_6
200
200
p_2_1D
p_2_1D
350
350
p_3
p_3
300
300
400
400
AmplitudeFourier
FourierSpectra
Spectra(cm/s)
(cm/s)
Amplitude
00
00
400
400
Synthetic
Synthetic accelerations
accelerations
and
and diffograms
diffograms
FAS
FAS
SS2c_3
SS2c_3
SS2c_4
SS2c_4
250
250
11
Case study examples
22
33
frequency
frequency(Hz)
(Hz)
44
55
66
50
50
00
00
11
22
33
frequency
frequency(Hz)
(Hz)
44
55
66
Parametric
Parametric study
study -- ESp
ESp towards
towards directivity
directivity
Case study examples
2nd rupture model: unilateral at 3 positions
Parametric
Parametric study
study -- ESp
ESp towards
towards directivity
directivity
Case study examples
2nd rupture model: unilateral at 3 positions
Parametric
Parametric study
study -- ESp
ESp towards
towards directivity
directivity
Case study examples
3rd rupture model: different vr at 3 positions
Parametric
Parametric study
study -- ESp
ESp towards
towards directivity
directivity
Case study examples
3rd rupture model: different vr at 3 positions
Parametric
Parametric study
study 44 -- ESp
ESp towards
towards directivity
directivity
PGV (cm/s)
PGV (cm/s)
100
100
PGV_NU
PGV_NU
PGV_FU
PGV_FU
PGV_NU_BED
PGV_NU_BED
PGV_FU_BED
PGV_FU_BED
SOM98_5.5
SOM98_5.5
AK00_5.5
AK00_5.5
RM00_5.5S
RM00_5.5S
10
10
1
1
8.6
8.6
8.7
8.7
8.8
8.8
8.9
8.9
9
9
Epicentral distance (km)
Epicentral distance (km)
9.1
9.1
9.2
9.2
9.3
9.3
9.4
9.4
100
100
1000
1000
PGA (cm/s**2)
PGA
(cm/s**2)
PGV
(cm/s)
PGV (cm/s)
PGV_NV
PGV_NV
PGA_NU
PGV_FV
PGA_NU
PGV_FV
PGA_FU
PGV_NV_BED
PGA_FU
PGV_NV_BED
PGA_NV
PGV_FV_BED
PGA_NV
PGV_FV_BED
PGA_FV
SOM98_5.5
PGA_FV
SOM98_5.5
AK00_5.5
AK00_5.5
RM00_5.5S
RM00_5.5S
10
100
10
100
10
10
8.6
1 8.6
1
8.6
8.6
Parametric study 4 - ES
8.7
8.7
8.7
8.7
8.8
8.8
8.8
8.8
8.9
9
8.9
9
Epicentral distance (km)
(km)
8.9 Epicentral distance
9
8.9
9
Epicentral distance (km)
Epicentral distance (km)
9.1
9.1
9.1
9.1
9.2
9.2
9.2
9.2
9.3
9.3
9.3
9.3
9.4
9.4
9.4
9.4
PGV - PGA
Parametric
Parametric study
study 44 -- ESp
ESp towards
towards directivity
directivity
250
250
uni_1
uni_1
unv_1
unv_1
150
150
uni_2
uni_2
unv_2
unv_2
SV(cm/s)
(cm/s)
SV
200
200
100
100
50
50
00
00
0.5
0.5
11
1.5
1.5
22
2.5
2.5
period
period(s)
(s)
33
3.5
3.5
44
4.5
4.5
55
4.5
4.5
55
1600
1600
1400
1400
uni_1
uni_1
uni_2
uni_2
SA(cm/s**2)
(cm/s**2)
SA
1200
1200
Parametric study 4 - ES
unv_1
unv_1
unv_2
unv_2
1000
1000
800
800
600
600
400
400
200
200
00
00
0.5
0.5
11
1.5
1.5
22
2.5
2.5
period
period(s)
(s)
33
3.5
3.5
44
response spectra
Implementation
Implementation of
of PSD
PSD tests
tests
(a) physical piers in the lab, (b), schematic representation
(c) workstations running the PSD algorithm and controlling the test
Case study examples
Force-displacement for Low-level earthquake experimental results Pier A40
Identification of insufficient seismic
detailing. tall pier A40, buckling of
longitudinal reinforcement at h = 3.5m
Damage pattern after the end of the High-Level Earthquake PSD test,
short pier A70.
Case study examples
Conclusions
Conclusions (?)
(?)
Case studies of seismic hazard assessment techniques
indicate the limits of the currently used methodologies,
deeply rooted in engineering practice, often conditioned by
the definition of the seismogenic zones.
Particularly important are the parameters used to
characterize the damage potential of earthquake ground
motion at a site.
The quantification of the critical ground motion (for PBD)
expected at a particular site can be identified in terms of
energy and displacement demands – the latter particularly
relevant for seismic isolation .
Conclusions
Conclusions
Conclusions -- 11
Different
Different ground
ground motions
motions at
at the
the Warth
Warth site
site have
have been
been studied
studied in
in
order
order to
to define
define the
the maximum
maximum excitation
excitation in
in longitudinal
longitudinal and
and
transverse
transverse direction,
direction, which
which are
are consistent
consistent both
both with
with the
the
Maximum
Maximum Credible
Credible Earthquake
Earthquake and
and with
with the
the Maximum
Maximum Design.
Design.
The
The main
main practical
practical conclusion
conclusion of
of our
our analysis,
analysis, verified
verified by
by
laboratory
laboratory experiments
experiments carried
carried out
out at
at JRC-ISPRA,
JRC-ISPRA, is
is that
that the
the
Warth
Warth bridge
bridge is
is likely
likely to
to well
well stand
stand the
the most
most severe
severe seismic
seismic input
input
compatible
compatible with
with the
the seismic
seismic regime
regime of
of the
the Eastern
Eastern Alps.
Alps.
With
With the
the parametric
parametric study
study we
we have
have defined
defined aa seismic
seismic sourcesourceWarth
Warth site
site configuration
configuration that
that provides
provides aa set
set of
of signals
signals whose
whose
seismic
seismic energy
energy is
is concentrated
concentrated around
around 11 Hz,
Hz, frequency
frequency that
that
corresponds
corresponds approximately
approximately to
to that
that of
of the
the fundamental
fundamental
transverse
transverse mode
mode of
of oscillation
oscillation of
of the
the bridge.
bridge.
Conclusions
Conclusions
Conclusions -- 22
The
The results
results show
show that
that lateral
lateral heterogeneity
heterogeneity can
can produce
produce strong
strong
spatial
spatial variations
variations in
in the
the ground
ground motion
motion even
even at
at small
small incremental
incremental
distances.
distances.
Such
Such variations
variations can
can hardly
hardly be
be accounted
accounted for
for by
by the
the stochastic
stochastic
models
models commonly
commonly used
used in
in engineering
engineering practice.
practice.
In
In absolute
absolute terms,
terms, the
the differential
differential motion
motion amplitude
amplitude is
is comparable
comparable
with
with the
the input
input motion
motion amplitude
amplitude when
when displacement,
displacement, velocity
velocity and
and
acceleration
acceleration domains
domains are
are considered.
considered.
On
On the
the base
base of
of the
the existing
existing empirical
empirical regression
regression relations
relations between
between
Intensity
Intensity and
and peak
peak values
values of
of ground
ground motion
motion aa general
general result
result of
of our
our
modeling
modeling is
is that
that the
the effect
effect of
of the
the differential
differential motion
motion can
can cause
cause an
an
increment
increment greater
greater than
than one
one unit
unit in
in the
the seismic
seismic intensity
intensity
experienced
experienced by
by the
the bridge,
bridge, with
with respect
respect to
to the
the average
average intensity
intensity
affecting
affecting the
the area
area where
where the
the bridge
bridge is
is built.
built.
Conclusions

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