11-paolucci istanbul 2012

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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


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A benchmark problem

Seismic response analysis of a diaphragm wall (Foti and Paolucci, 2012)

60 30 60

5

5

5

5

10

10

10

5

55m

150 m

variabilevariabile

z

Vs(z)

variable variable

bedrock Points of control for acceleration

A

B

C

D E

A

B

C

3


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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 NSRecording device KINEMETRICS SMA-1 (analo KINEMETRICS SMA-1 (analog)Uncorrected amax 101 cm/s

2 129 cm/s

2

Corrected acceleration time histories from:

1) European Strong Motion Database

2) ITalian ACelerometric Archive

3) PEER strong motion database



Selection of input records for non-linear time-history analyses

4


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ATINA NS record

5


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ATINA NS record

ITACA pad-strip

procedure to safely

remove zero-paddingand ensure compatibility

of SM records

6

tapering + detrend on displacements


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Atina


simulations of soil-structure interaction problems8


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Displacement time histories at top of the wallAtina 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]

displacemen

ts[cm]

ITACA

PEER

ESMDB




11/37Roberto Paolucci-14

-12

-10

-8

-6

-4

-2

0

-400 -300 -200 -100 0

peak bending moment [kNm/m]

depth[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 ]

depth[m]

-0.025 -0.020 -0.015 -0.010 -0.005 0.000

peak displacement [m]

itacapeer

esmdb

conf statica

(a) (b)

end of excavation



peak values of displacement and bending momentAtina record

11



BagnoliBending Moment

[kNm/m]Displacement

[cm]

Left wall Right wall Left wall

Right

wallITACA -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



Atina

12



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.





Outline 14

Selection of real accelerograms based on

displacement-spectrum compatibility



S l ti f l l b d di l t



15

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



16Reliability of long-period response spectral ordinates from digital accelerograms

After Paolucci et al., 2008

Zihuatanejo

Jan 11, 1997 Michoacn

(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 1020 sec (...) Akkar and Boore (2009)



1717

Seismic Hazard Map of Italy

(02 s)

DPC-INGV Project S12005-2007

http://esse1.mi.ingv.it

Probabilistic seismic hazard studies in Italy



1818

DPC-INGV Project S52005-2007

Faccioli and Villani, 2009

Long period PSHA in Italy: maps of D10

Probabilistic seismic hazard studies in Italy



1919Probabilistic seismic hazard studies in Italy

Long period PSHA in Italy: map of TD



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)

Selection of real accelerograms based on displacement


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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-


Joint research activity of Politecnico di Milano & Universit Federico II Napoli


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FDTT

TTTTFCSDFDTTT

CSDTTT

T

T

TFSaTTT

NTCseeTT

TS

F

EF

FcFE

cED

CgDC

C

D

10

1010

10

2

2

04

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,TDfrom Project S5, while ag, , S, Cc, F0, TC, TE, TFcome from NTC08

: factor introduced to match short and long

periods (

=1 for constant velocity)

F: long period site factor (from S5 project)


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Italian norms NTC08

Long period PSHA

Connecting branch T-



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= 0.85 -1.4



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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 10 FDd 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



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27

Site factors

NTC08 TDSI


31Selection of real accelerograms based on displacement-


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3232SIMBAD: Selected Input Motions for displacement Based


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3232SIMBAD: Selected Input Motions for displacement-BasedAssessment and Design

Worldwideregions

EC8Sitec

lasses


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3434S ft REXEL DISP 1 1 ( l i it)


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3434Software REXEL-DISP v 1.1 (www.reluis.it)

available at http://www.reluis.it

35Selection of real accelerograms based on displacement-


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3636E l f li ti


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Dependence on the target spectrum (NTC08 vs TDSI)

Aquila, TR = 475 years

%26%,11 max avg %27%,6 max avg


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Dependence on seismicity level

(Aquila vs Udine, TR = 475 yr, TDSI)

%27%6 max avg %28%9 max avg


3838Examples of application


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3838

Broadband compatibility

(Aquila, TR = 475 years, TDSI)


39Practical hints for using REXEL DISP


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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

4040Concluding remarks


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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 systemsnon-linear dynamic SSIsoil stability problems)

... but ...

the accelerograms should be selected from high-quality strong-motion

databases, covering the seismic hazard levels and site conditions ofinterest;

the target spectrum should be carefully defined based on seismic hazard

studies at long periods


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11-paolucci istanbul 2012

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