3. Intensity Measure Calculation

The imcalculator class computes intensity measures (IMs) from an acceleration time series. Supported IMs include response spectra, peak ground motion parameters (PGA, PGV, PGD), spectral accelerations, average spectral acceleration (AvgSA), Arias Intensity, Cumulative Absolute Velocity (CAV), significant duration, the filtered incremental velocity (FIV3), and orientation-independent spectral acceleration (RotDxx).

• 3.1. Initialisation
  • imcalculator.__init__()
• 3.2. Response Spectrum
  • imcalculator.get_spectrum()
• 3.3. Spectral Acceleration
  • imcalculator.get_sa()
• 3.4. Average Spectral Acceleration
  • imcalculator.get_saavg()
• 3.5. User-Defined Average Spectral Acceleration
  • imcalculator.get_saavg_user_defined()
• 3.6. Velocity and Displacement History
  • imcalculator.get_velocity_displacement_history()
• 3.7. Amplitude Intensity Measures
  • imcalculator.get_amplitude_ims()
• 3.8. Arias Intensity
  • imcalculator.get_arias_intensity()
• 3.9. Cumulative Absolute Velocity
  • imcalculator.get_cav()
• 3.10. Significant Duration
  • imcalculator.get_significant_duration()
• 3.11. Filtered Incremental Velocity
  • imcalculator.get_FIV3()
• 3.12. Orientation-Independent Spectral Acceleration (RotDxx)
  • imcalculator.get_rotdxx()

3.13. References

1. Cordova, P.P., Deierlein, G.G., Mehanny, S.S., and Cornell, C.A. (2000). “Development of a two-parameter seismic intensity measure and probabilistic assessment procedure” in Proceedings of the 2nd US–Japan Workshop on Performance-Based Earthquake Engineering Methodology for RC Building Structures (Sapporo, Hokkaido, 2000).

2. Eads, L., Miranda, E., and Lignos, D.G. (2015). “Average spectral acceleration as an intensity measure for collapse risk assessment”, Earthquake Engineering and Structural Dynamics, 44, 2057–2073. doi: 10.1002/eqe.2575.

3. Kempton, J.J., and Stewart J.P. (2006). “Prediction equations for significant duration of earthquake ground motions considering site and near-source effects”, Earthquake Spectra, 22(4), 985-1013.

4. Arias, A. (1970). “A measure of earthquake intensity”, in Seismic Design for Nuclear Power Plants (R.J. Hansen, ed.). The MIT Press, Cambridge, MA. 438-483.

5. Dávalos, H. and Miranda, E. (2019). “Filtered incremental velocity: A novel approach in intensity measures for seismic collapse estimation.” Earthquake Engineering & Structural Dynamics, 48(12), 1384–1405. DOI: 10.1002/eqe.3205.

6. Boore, D.M. (2010). “Orientation-independent, nongeometric-mean measures of seismic intensity from two horizontal components of motion.” Bulletin of the Seismological Society of America, 100(4), 1830–1835. DOI: 10.1785/0120090400.

7. Trifunac, M.D. and Brady, A.G. (1975). “A study on the duration of strong earthquake ground motion.” Bulletin of the Seismological Society of America, 65(3), 581–626.