An Introduction toUtility Software for Data

Processing (USDP)Sinan Akkar

Earthquake Engineeri ng Research Center

Middel East Technical University Earthquake Engineering Earthquake Engineering Research CenterResearch Center

Middle East Technical Middle East Technical UniversityUniversity

Utility Software for Data Utility Software for Data ProcessingProcessing

4th BSHAP Project Workshop16-17 December 2008, Budva, Montenegro

USDP: data processing and USDP: data processing and spectral analysisspectral analysis

2Sinan Akkar

q Record processing through fil tering, baseline correct ion or combinat ion of both (blpadflt.exe by D. Boore)

q Fourier Analysis (smc2fs2.exe by D. Boore)

q Response spec trum for linear and nonlinear oscill ator response (sa4nor.exe by Ö. Kale and S. Akkar)

ContributorsContributors

3Sinan Akkar

Main Components:S.Akkar (Nonlinear/Linear Spectrum)Ö.Kale (Nonlinear/Linear Spectrum)D.M. Boore (Processing & F AS)E.V. Çektimur (Graphical interface)S.Baş (Graphical interface)

Outline of this presentationOutline of this presentation

Sinan Akkar 4

o Basic USDP str uctureo Main features (including its i terative character) using simple case s tudies

Ø data processing (*)

Ø Fourier spectrumØ nonlinear spect rum

(*) Discussions on optimum data proc essing parameters are out of scope of this presentation

Acknowledgment

Sinan Akkar 5

o Data processing and FAS case studies discussed in this presentation are taken from TSPP manual (http://quake.wr.usgs.gov/~boore/software_online.htm).

o Record used for the nonlinear response spectrum case study is taken from the dataset compiled for the Turkish strong-motion data project (T-NSMP, TUBITAK 105G016)

USDP Major CapabilitiesUSDP Major Capabilities

Sinan Akkar 6

Data Processing

Data Processing

Fourier Amplitude Spectrum

(FAS)

Fourier Amplitude Spectrum

(FAS)

Linear and Nonlinear Spectral Analysis

Linear and Nonlinear Spectral AnalysisBaseline

correctionBaseline correction

Acausal/Causal digital filteringAcausal/Causal digital filtering

Hybrid (Combination of baseline correction and digital filtering)

Hybrid (Combination of baseline correction and digital filtering)

Constant ductilityConstant ductility

Constant strengthConstant strength

Constant base shear coefficientConstant base shear coefficient

Smoothing option with different techniques)

Smoothing option with different techniques)

Interpolation option for a given frequency interval

Interpolation option for a given frequency interval

Powerful graphical interface to display the resultsPowerful graphical interface to display the results

Data processingData processing(Basic filtering with / without (Basic filtering with / without

tapering)tapering)

Sinan Akkar 7

Start Data Processing Wizard Start Data Processing Wizard

Sinan Akkar 8

Two records to process

Two records to process

Records can be viewed by clicking on “Quick view”

Records can be viewed by clicking on “Quick view”

Remove preRemove pre --event mean (zerothevent mean (zeroth --orderorder--correction, zoc) correction, zoc)

Sinan Akkar 9

Step #1:Remove mean of first 8 sec from the entire lengths of both records

Step #2:Click “next” until the “spectrum”window appears

Step #3:100 log-spaced period values between 0.01 sec to 50 sec for 5% damping spectrum

Step #4:Hit “Skip to Last Page” to finalize the wizard

Results of zoc for Example 1

Sinan Akkar 10

After h

itting

“close”

Illustrations (zoc displacements)

Sinan Akkar 11

Artifacts that Artifacts that result in longresult in long--period period fluctuationsfluctuations

High-pass (acausal) filtering of zoc record

Sinan Akkar 12

You can duplicate the folders and drag-and-drop the outputs of one folder into the other

High-pass acausal filter with 0.02 Hz. Filter roll-of is such that filter decays as f8 at low frequencies

Choose “Acausal”filtering option and click on “Next”

Results of low-cut filtering for Example 1

Sinan Akkar 13

After hiting

“close”

Illustrations (low -cut filtered records)

Sinan Akkar 14

Filter transients due to acausal filtering. Apply tapering to reduc e their effects

Filter transients due to acausal filtering. Apply tapering to reduc e their effects

Tapering and Acausal filteringTapering and Acausal filtering

Sinan Akkar 15

Duplicate the previous folder

Apply tapering to the last 20 sec of the record

Click on “Skip to Last Page” to finalize the wizard

Results of low-cut filtering and tapering for Example 1

Sinan Akkar 16

After hiting

“close”

Illustrations (low -cut filtered and tapered records)

Sinan Akkar 17

Filter transients decreased significantly

Filter transients decreased significantly

Compare Spectral Compare Spectral DisplacementsDisplacements

Sinan Akkar 18

Plot the spectral curves of “zoc” (red) and acausally filtered data with (green) and without (blue) tapering

Plot the spectral curves of “zoc” (red) and acausally filtered data with (green) and without (blue) tapering

Filtering with and without tapering makes a di fference in SD at periods relatively smaller than filter cut-off period (Tc = 50 sec). This indicates filter transients are influential on SD calculations for this particular record

Filtering with and without tapering makes a di fference in SD at periods relatively smaller than filter cut-off period (Tc = 50 sec). This indicates filter transients are influential on SD calculations for this particular record

Fourier Amplitude Spe ctrumFourier Amplitude Spe ctrum(Unsmoothed / smoothed FAS) (Unsmoothed / smoothed FAS)

Sinan Akkar 19

FAS – no smoothing

Sinan Akkar 20

The FAS of zoc and acausally f iltered (with/without tapering )accelerograms are calculated. Click on “Next” after adding these files.

The FAS of zoc and acausally f iltered (with/without tapering )accelerograms are calculated. Click on “Next” after adding these files.

Specify “no smoothing” in the calculations

Sinan Akkar 21

No smoothing

No smoothing

DC comp. is removed

DC comp. is removed

Click on “Next”

Click on “Next”

Illustrations (FAS – no smoothing)

Sinan Akkar 22

Click on “Close” when the runs finish

Filter cut-off frequency (0.02 Hz)

Choose a fi lter cut-off higher than 0.02 Hz to have faster decay at low frequencies

Choose a fi lter cut-off higher than 0.02 Hz to have faster decay at low frequencies

FAS – smoothed – freq. indep

Sinan Akkar 23

Click on this button to choose the smoothing parameters

Click on this button to choose the smoothing parameters

Smoothing over frequency-independent intervals (Define the number of weights either for “Box” or “Triangular” smoothing operators.

Smoothing over frequency-independent intervals (Define the number of weights either for “Box” or “Triangular” smoothing operators.

Smoothing over frequency-dependentintervals (smoothing band is controlled by width to central frequency ratio). This option corresponds to constant width in log -frequency

Smoothing over frequency-dependentintervals (smoothing band is controlled by width to central frequency ratio). This option corresponds to constant width in log -frequency

Triangular function with weights 0, ¼, ½, ¼, 0.

Triangular function with weights 0, ¼, ½, ¼, 0.

FAS – smoothed – freq. dep

Sinan Akkar 24

Same exercise but this time with log -spaced triangular smoothing operator.

Same exercise but this time with log -spaced triangular smoothing operator.

Comparison between different smoothing options

Sinan Akkar 25

Freq. indep smoothing

Freq. indep smoothing

Freq. dep smoothing

Freq. dep smoothing

Sinan Akkar 26

Nonlinear SpectrumNonlinear Spectrum(Constant ducti lity, strength and base(Constant ducti lity, strength and base --

shear coefficient) shear coefficient)

Data Input and Running Nonlinear Spectra

Sinan Akkar 27

Data input is similar to the previously shown processing and FAS wizards.

Data input is similar to the previously shown processing and FAS wizards.

The options either for running spectral analysis or performing response history analysis of a particular oscillator are given in this window.

The options either for running spectral analysis or performing response history analysis of a particular oscillator are given in this window.

In this example, nonlinear spectral analysis are conducted for a period interval of 0.05s - 3.0s. There are linearly-spaced 31 discrete period values.

In this example, nonlinear spectral analysis are conducted for a period interval of 0.05s - 3.0s. There are linearly-spaced 31 discrete period values.

Hysteretic models and rele vant input

Sinan Akkar 28

There are 10 hysteretic models ranging from elastoplastic to Takeda stiffness and strength degrading.

There are 10 hysteretic models ranging from elastoplastic to Takeda stiffness and strength degrading.

Some of these models require additional input parameters

Some of these models require additional input parameters

Constant-strength spectra for an elastoplastic system

Sinan Akkar 29

Click “Next” to finish the runClick “Next” to finish the run

Necessary parameters to define EPP behavior with R = 1,…,6

Necessary parameters to define EPP behavior with R = 1,…,6

Illustration of Results

Sinan Akkar 30

Inelastic to elastic spectral displacement ratios for a set of R values

Inelastic to elastic spectral displacement ratios for a set of R values

Spectral dispalcements for a set of R values

Spectral dispalcements for a set of R values

Conclusions

Sinan Akkar 31

o USDP is a user-friendly data processing and spectral analysis sof tware. The software makes use of a set of executable codes of D.M Boore, Ö. Kale and S. Akkar and combines them under a powerful graphical interf ace.

o A given ground motion can be analyzed for different processing options in a rapid manner. T his can be advantageous for research.

o This is also the case for elastic and inelastic spectral analysis.

o A built-in help menu can show the effective use of this software to the users. A handbook is also in preperation that discusses processing techniques as well as spectral calculations.