Signal Processing and Analysis Tools for Civil Engineers

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Strong Ground Motion (SGM) Module

Purpose

The Strong Ground Motion Module is used for analyse the data form strong ground motions measured by seismic recorders (e.g. GSR files), but it can also be used with other sources, like data from tests (e.g. test's earthquake scenario analysis).

This module is unit dependent, so the time histories have to be defined with coherent units (accelerations time histories in acceleration units, etc).

 

Main Features

  • Compute the accelerations, velocities and displacements TH (with automatic/manual signal processing);

  • Compute several frequency domain functions (Response spectra, Fourier amplitude and phase, Power spectrum, PSD, Husid Plot and Energy Flux Plot);

  • Compute several SGM parameters: (PGA, PGV, PGD; Peak velocity and acceleration ratio; Arias Intensity; A95 parameter; t05 parameter; t95 parameter; Significant duration; Characteristic intensity; Predominant period; Mean period; Sustained maximum acceleration; Acceleration Spectrum Intensity; Velocity Spectrum Intensity);

  • Automatic report generation;

  • Automatic unit conversion.

Calculations

Calculation of the parameters

 

Reports

Click here to view an example

 

(Click to enlarge)

 

Legend

  1. Run/Help/Stop buttons;

  2. Channel source definition;

  3. Channel's units selector;

  4. Fourier Filters;

  5. Integration and derivation parameters;

  6. Baseline correction using polynomial functions;

  7. Calculated accelerations, velocities or displacements charts;

  8. Functions chart;

  9. Parameters calculation and display;

  10. Response spectra settings;

  11. Common spectra parameters;

  12. Standard report export.

 

Parameter Calculation

 

Name of the parameter: How is calculated:
Peak ground acceleration (PGA)
Peak ground velocity (PGV)
Peak ground displacement (PGD)
Peak velocity and acceleration ratio (Vmax/amax)
Arias Intensity (Ia)
A95 parameter (A95) Is the maximum value of acceleration that corresponds to 95% of the Arias intensity value.
t05 parameter (t05) Is the time where 5% of the Arias intensity is reached.
t95 parameter (t95): Is the time where 95% of the Arias intensity is reached.
Significant duration (SD)
Characteristic intensity (Ic)
Predominant period (Tp) Is the period where is reached the maximum spectral accelerations in an acceleration response spectra (damping=5%)
Mean period (Tm)
where:  Ci are the Fourier amplitudes at fi frequencies between 0.25 and 20 Hz.
Sustained maximum acceleration (SMA) Is the third maximum acceleration measured.
Sustained maximum Velocity (SMV) Is the third maximum velocity measured.
Acceleration Spectrum Intensity (ASI)
Velocity Spectrum Intensity (VSI)

(also known as Housner Intensity)

 

Note: Most of these parameters were inspired in the excellent software SeismoSignal from SeismoSoft. Please take a look at their software and site.

 

Last updated: 15-08-2006 18:24