Encyclopedia of Earthquake Engineering

2015 Edition
| Editors: Michael Beer, Ioannis A. Kougioumtzoglou, Edoardo Patelli, Siu-Kui Au

Conditional Spectra

  • Ting LinEmail author
  • Jack Baker
Reference work entry
DOI: https://doi.org/10.1007/978-3-642-35344-4_386


Conditional mean spectrum; Hazard-consistent ground motion selection; Response spectrum; Scenario spectrum; Spectral shape


The conditional spectrum (CS) is a response spectrum that specifies the probability distribution of spectral accelerations, Sa, over a range of periods of vibration, Ti, conditioned on spectral acceleration at a conditioning period, T*, of interest. The conditional spectrum utilizes the correlations between spectral accelerations at different periods (e.g., Baker and Jayaram 2008) to compute the expected (logarithmic mean) response spectrum (Baker and Cornell 2006; Baker 2011) and additionally account for the variability (variance) of the response spectra (Jayaram et al. 2011; Lin et al. 2013a). Assuming the distribution of logarithmic spectral accelerations is multivariate normal (Jayaram and Baker 2008), then the first two moments (i.e., the means, standard deviations, and correlations) fully describe the conditional spectrum. The CS...

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Copyright information

© Springer-Verlag Berlin Heidelberg 2015

Authors and Affiliations

  1. 1.Department of Civil, Construction and Environmental EngineeringMarquette UniversityMilwaukeeUSA
  2. 2.Stanford UniversityStanfordUSA