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Response Spectrum Wizard : Damping

Scale response spectrum​

When a constant or modal damping option has been selected the used is given the option of scaling the spectrum to allow for different levels of damping.

  • Code defined scaling only – the spectrum is modified if the code allows for this, otherwise it is left unchanged.
  • Scale by ln⁡(100/η)ln⁡(20)\frac{\ln(100/η)}{\ln(20)} [ISO19901-2] – this applies a scaling of ln⁡(100/η)ln⁡(20)\frac{\ln(100/η)}{\ln(20)} as outlined in ISO 19901-2 over the whole spectrum
  • Newmark-Hall : 50th percentile – the median acceleration modifiers from Newmark and Hall (1982) are applied to the calculated spectral values
  • Newmark-Hall : 84th percentile – the acceleration modifiers at one standard deviation from Newmark and Hall (1982) are applied to the calculated spectral values