the importance of strong-motion data in engineering seismology and earthquake engineering
DESCRIPTION
The importance of strong-motion data in engineering seismology and earthquake engineering Roberto PAOLUCCI Department of Structural Engineering Politecnico di Milano, ITALY. Outline. Influence of strong motion processing on numerical simulations of soil-structure interaction problems. - PowerPoint PPT PresentationTRANSCRIPT
The importance of strong-motion data in engineering seismology and earthquake
engineering
Roberto PAOLUCCI
Department of Structural Engineering
Politecnico di Milano, ITALY
Roberto Paolucci
Outline 2
Selection of real accelerograms based on displacement-spectrum compatibility
Influence of strong motion processing on numerical simulations of soil-structure interaction problems
Roberto Paolucci
Influence of strong motion processing on numerical simulations of soil-structure interaction problems
A benchmark problem
Seismic response analysis of a diaphragm wall (Foti and Paolucci, 2012)
60 30 60
55
55
10
10
10
5
55
m
150 m
variabilevariabile
z
Vs(z) variable variable
bedrock Points of control for acceleration
A
B
C
D E A’
B’
C’
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Roberto Paolucci
Earthquake Val Comino 7/5/1984 M5.9 Irpinia 23.11.1980 M6.9 Recording Station Atina Bagnoli Irpino Epicentral Distance 10.3 km 22.6 km Component NS NS Recording device KINEMETRICS SMA-1 (analog) KINEMETRICS SMA-1 (analog) Uncorrected amax 101 cm/s2 129 cm/s2
Corrected acceleration time histories from:
1) European Strong Motion Database 2) ITalian ACelerometric Archive 3) PEER strong motion database
Influence of strong motion processing on numerical simulations of soil-structure interaction problems
Selection of input records for non-linear time-history analyses
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Roberto Paolucci
Influence of strong motion processing on numerical simulations of soil-structure interaction problems
ATINA NS record
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Roberto Paolucci
Influence of strong motion processing on numerical simulations of soil-structure interaction problems
ATINA NS record
ITACA “pad-strip” procedure to safely remove zero-padding and ensure compatibility of SM records
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tapering + detrend on displacements
Roberto Paolucci
Influence of strong motion processing on numerical simulations of soil-structure interaction problems
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Roberto Paolucci
Atina
Influence of strong motion processing on numerical simulations of soil-structure interaction problems
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Roberto Paolucci
Bagnoli
Influence of strong motion processing on numerical simulations of soil-structure interaction problems
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Roberto Paolucci
Displacement time histories at top of the wall – Atina record
-1.0
-0.5
0.0
0.5
1.0
1.5
2.0
2.5
0 2 4 6 8 10
time [s]
dis
pla
cem
ents
[cm
]
ITACA
PEER
ESMDB
Influence of strong motion processing on numerical simulations of soil-structure interaction problems
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Roberto Paolucci
-14
-12
-10
-8
-6
-4
-2
0
-400 -300 -200 -100 0
peak bending moment [kNm/m]
dept
h [m
]
0 100 200 300 400
peak bending moment [kNm/m]
itaca
peer
esmdb
conf statica
(a) (b)
end of excavation
-14
-12
-10
-8
-6
-4
-2
0
0.000 0.005 0.010 0.015 0.020 0.025
peak displacement [m]
dept
h [m
]
-0.025 -0.020 -0.015 -0.010 -0.005 0.000
peak displacement [m]
itaca
peer
esmdb
conf statica
(a) (b)
end of excavation
Influence of strong motion processing on numerical simulations of soil-structure interaction problems
peak values of displacement and bending moment – Atina record
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Roberto Paolucci
Bagnoli Bending Moment
[kNm/m] Displacement
[cm]
Left wall Right wall Left wall Right wall
ITACA -441.1 500.3 14.0 -12.6
PEER -462.0 472.6 10.8 -11.7
ESMDB -449.0 505.3 -54.6 -59.0
Bending Moment
[kNm/m] Displacement
[cm]
Left wall Right wall Left wall Right wall
ITACA -372.0 354.9 2.50 -2.05
PEER -370.1 349.7 1.99 -2.06
ESMDB -375.7 354.0 2.56 -1.90
Influence of strong motion processing on numerical simulations of soil-structure interaction problems
Atina
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Roberto Paolucci
Summary
Consequences of processing procedure Limited on bending moments Relevant (20-30%) on displacements (important for PBD)
Differences observed on a relatively rigid system (conservative design with PS approach of EC8). Likely higher effects on more flexible systems
“Engineering” rules to avoid gross errors in the use of real accelerograms used as input motion for non-linear dynamic soil-structure interaction analyses: do not manipulate the corrected record provided by the database; prefer records corrected by acausal filtering; prefer digital records; check, before the numerical simulation, that velocities and displacements resulting
by integration of the input acceleration are not affected by unphysical drifts.
Influence of strong motion processing on numerical simulations of soil-structure interaction problems
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Roberto Paolucci
Outline 14
Selection of real accelerograms based on displacement-spectrum compatibility
Influence of strong motion processing on numerical simulations of soil-structure interaction problems
Roberto Paolucci
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Introductory works at Politecnico from 2000 to 2010, for characterization of long period ground motion
displacement spectra at long periods (→ Faccioli et al., 2004)
Study on the reliability of long period spectral ordinates from digital accelerograms (→ Paolucci et al., 2008)
GMPE at long periods (→ Cauzzi and Faccioli, 2008)
PSHA at long periods for Italian sites (→ Faccioli and Villani, 2009)
Selection of real accelerograms based on displacement-spectrum compatibility
Roberto Paolucci
16Reliability of long-period response spectral ordinates from digital accelerograms
After Paolucci et al., 2008
Zihuatanejo Jan 11, 1997 Michoacán (MW7.1, Re=143 km)
Morge Sep 8, 2005 Pennine Alps (MW4.4, Re=17 km)
"the elastic spectra from the most basic processing, in which only the pre-event mean is removed from the acceleration time series, do not diverge from the baseline-corrected spectra until periods of 10–20 sec (...) Akkar and Boore (2009)
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1717
Seismic Hazard Map of Italy (0 – 2 s)
DPC-INGV Project S1 – 2005-2007
http://esse1.mi.ingv.it
Probabilistic seismic hazard studies in Italy
Roberto Paolucci
1818
DPC-INGV Project S5 – 2005-2007Faccioli and Villani, 2009
Long period PSHA in Italy: maps of D10
Probabilistic seismic hazard studies in Italy
Roberto Paolucci
1919Probabilistic seismic hazard studies in Italy
Long period PSHA in Italy: map of TD
Roberto Paolucci
2020Probabilistic seismic hazard studies in Italy
How to match short and long period PSHA results and put them in a format for engineering applications ?
→ towards a target displacement spectrum for Italian sites (TDSI)
Roberto Paolucci
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SIMBAD: a database for engineering analyses of long period ground motion
Target displacement spectra for Italian sites
Software REXEL-DISP v 1.1
Examples of application
Selection of real accelerograms based on displacement-spectrum compatibility
Joint research activity of Politecnico di Milano & Università Federico II Napoli
Roberto Paolucci
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FDTTTT
TTFCSDFDTTT
CSDTTT
T
T
TFSaTTT
NTCseeTT
TS
F
EF
FcFE
cED
CgDC
C
D
10
1010
10
2
2
0 4
08
)(
A Target Displacement Spectrum for Italian Sites
Broadband displacement spectrum for design, matching the Italian NTC08 regulations at short periods with the long period PSHA
1
20
102
log4
log
D
C
Dg
c
T
T
TFa
CD
375.030/800 SVF
D10,TD from Project S5, while ag, , S, Cc, F0, TC, TE, TF come from NTC08
: factor introduced to match short and long periods (=1 for constant velocity)
F: long period site factor (from S5 project)
Roberto Paolucci
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Italian norms NTC08
Long period PSHA
Connecting branch T-α
A Target Displacement Spectrum for Italian Sites
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= 0.85 -1.4
A Target Displacement Spectrum for Italian Sites
Roberto Paolucci
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Comparison of TDSI with NTC08 (Italian seismic regulations)
DC
DCgg
TTa
TTaSdd
max
max
025.0
025.0
NTC08 TDSI
DC TTFaMSD 0max025.0 CCSDMSD 10FDd 10max
9.10.1/800 375.030 SVF
A: VS30 = 800 m/s; B: VS30 = 580 m/s; C/E: VS30 = 270 m/s; D: VS30 = 140 m/s
A Target Displacement Spectrum for Italian Sites
Roberto Paolucci
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Site factors
NTC08 TDSI
A Target Displacement Spectrum for Italian Sites
Roberto Paolucci
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SIMBAD: a database for engineering analyses of long period ground motion
Target displacement spectra for Italian sites
Software REXEL-DISP v 1.1
Examples of application
Selection of real accelerograms based on displacement-spectrum compatibility
Roberto Paolucci
3232SIMBAD: Selected Input Motions for displacement-Based Assessment and Design
Wor
ldw
ide
regi
ons
EC8
Site
cla
sses
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SIMBAD: a database for engineering analyses of long period ground motion
Target displacement spectra for Italian sites
Software REXEL-DISP v 1.1
Examples of application
Selection of real accelerograms based on displacement-spectrum compatibility
Roberto Paolucci
3434Software REXEL-DISP v 1.1 (www.reluis.it)
available at http://www.reluis.it
Roberto Paolucci
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SIMBAD: a database for engineering analyses of long period ground motion
Target displacement spectra for Italian sites
Software REXEL-DISP v 1.1
Examples of application
Selection of real accelerograms based on displacement-spectrum compatibility
Roberto Paolucci
3636
Dependence on the target spectrum (NTC08 vs TDSI) Aquila, TR = 475 years
%26%,11 max avg %27%,6 max avg
Examples of application
Roberto Paolucci
3737
Dependence on seismicity level(Aquila vs Udine, TR = 475 yr, TDSI)
%27%6 max avg %28%9 max avg
Examples of application
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3838
Broadband compatibility(Aquila, TR = 475 years, TDSI)
Examples of application
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Type of application Hints
Search for 7 one- or two-component displacement-spectrum compatible accelerograms
- preference to unscaled records - use of wide magnitude and distance intervals (e.g., default values: 5-7 and 0-30 km) and any site class (due to the limited number of records on some soil types in the SIMBAD database) - ensure spectral matching over a rather broad range of vibration periods (e.g., default values: 0.5-8 s) - when searching for scaled records the use of limited magnitude and distance range is found to be more feasible.
Search for displacement-spectrum compatible individual records
- preference to unscaled records - use of wide magnitude and distance intervals (e.g., default values: 5-7 and 0-30 km) and any site class- limit spectral compatibility to relatively small period ranges (e.g., 1-3 s)
Search for 30 displacement-spectrum compatible accelerograms
- preference to unscaled records when selecting 30 one-component records but the use of scale factors is advisable when searching for 30 two-component records. - use of wide magnitude intervals (e.g., default values: 5-7) and any site class- ensure spectral matching over a rather broad range of vibration periods (e.g., default values: 0.5-8 s) - when searching for scaled records the use of limited magnitude and distance range is found to be more feasible.
Practical hints for using REXEL-DISP
Roberto Paolucci
4040Concluding remarks
Why using spectral displacements as a target for ground motion selection?
the target magnitude range is “naturally” satisfied;
no need to scale accelerograms;
a broadband spectral compatibility is easily achieved (→ NLTHA of MDOF systems – non-linear dynamic SSI – soil stability problems)
... but ...
the accelerograms should be selected from high-quality strong-motion databases, covering the seismic hazard levels and site conditions of interest;
the target spectrum should be carefully defined based on seismic hazard studies at long periods
Roberto Paolucci
Thank you !
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