E-CMS: A new design spectrum for nuclear structures in high levels of seismic hazard

Mousavi, Mehdi; Shahri, Mohamadreza; Azarbakht, Alireza

doi:10.1016/j.nucengdes.2012.06.019

Cited by 8 publications

(5 citation statements)

References 15 publications

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“…Other complementary selection criteria include the soil profile, which may alter and/or amplify response spectra at specific periods of interest and the strong motion duration causing damage accumulation (Iervolino et al 2006). Spectral matching between a target spectrum and the response spectrum (Bommer et al 2003;Ambraseys et al 2004), which can also take into account the spectral shape (Baker and Cornell 2005;Mousavi et al 2012), may also be used for assessment of seismic vulnerability. The spectral shape is considered by means of the parameter ''epsilon'' (''e'') that expresses the number of standard deviations by which a given IM differs from the mean predicted IM value, where both values are expressed in logarithmic terms.…”

Section: Introductionmentioning

confidence: 99%

Efficiency of alternative intensity measures for the seismic assessment of monolithic free-standing columns

Pappas

Sextos

Porto

et al. 2016

Bull Earthquake Eng

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This paper deals with the dynamic response of a free-standing ancient column in the Roman Agora of Thessaloniki, Greece as a means to shed more light on the complex behaviour of rocking bodies under seismic excitation. Numerical analyses utilizing discrete element method were carried out with the use of multiple seismic records selected based on the disaggregation of the seismic hazard for the region of interest. To identify their impact on structural performance, earthquake Intensity Measures, such as Peak Ground Acceleration and Peak Ground Velocity are examined for the case of a column that sustained no visible permanent deformations during the Ms = 6.5 Thessaloniki earthquake of 1978. The analysis revealed a weak correlation of PGA and PGV with the response results and a significant influence of the mean frequency (f m ) of the seismic motion. No coupling was found between the maximum displacement of the top during the oscillation and the permanent post-seismic deformations. The complementarity of both earthquake Intensity Measures in the structural vulnerability assessment is also depicted.

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Section: Introductionmentioning

confidence: 99%

Efficiency of alternative intensity measures for the seismic assessment of monolithic free-standing columns

Pappas

Sextos

Porto

et al. 2016

Bull Earthquake Eng

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“…As seen in Figure 7(a) and (b), the Eta based median collapse capacity is a little higher than the Epsilon based median collapse capacity, especially when the variations of the target spectrum are taken into consideration. This is an evidence that the conventional Epsilon based target spectrum can result in underestimation of structural demand [22].…”

Section: Mean Annual Frequency Of Collapse As a Function Of Target Pementioning

confidence: 88%

The dependence of conditional spectra on the choice of target periods

Azarbakht

Ghodrati

2017

Scientia Iranica

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Abstract. The dependence of Conditional Mean Spectrum (CMS) and the corresponding standard deviation on di erent target period values were investigated in this paper by means of two types of target spectra, i.e. based on Epsilon and Eta indicators. The structural collapse capacities as well as the Mean Annual Frequency (MAF) of exceeding a limit state were taken into consideration. The results showed that the dependence of Eta-based CMS (ECMS) on the choice of target period was insensitive to the target period in the case of MAF calculation. However, this dependence was meaningfully low in the case of ECMS when compared to CMS in intensity-based ground motion selection. The Sum of the Squared Error (SSE) was utilized to compare di erent CMS cases. SSE was less in shorter return periods, e.g. 75 years, than in longer return periods, e.g. 2475 years. This dependence is also a function of choosing attenuation relationships. Therefore, four Next Generation Attenuation (NGA) relationships were employed in this study. In general, ECMS showed less dependence in all cases than the conventional CMS did.

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“…It has a higher level of correlation with the nonlinear structural response when compared with the case of the conventional spectral acceleration epsilon. For this reason, it was used as a new proxy for the calculation of the conditional spectra . The target spectral acceleration epsilon and the target eta are necessary to calculate the conditional spectra.…”

Section: Why Do We Need Conditional Spectra?mentioning

confidence: 99%

“…A closed form model was proposed in a previous study to obtain

ρ'_{(η (T), η (T^{*}))}

. The stepwise calculation of the conditional spectra, based on the exact eta, is as follows: Considering the seismic source and its characteristics and the structural properties like the first mode period ( T *), PSHA can be performed, and the results can be obtained regarding S a versus hazard and PGV versus hazard. By considering a hazard level and obtaining its equivalent S a , it is possible to compute a related probability density function based on Equation and the mean value of magnitude using Equation .…”

Section: Why Do We Need Conditional Spectra?mentioning

confidence: 99%

“…Spectral shape indicators, for example, epsilon and eta, have been recently proposed. Conditional mean spectra have been obtained by employing the prementioned indicators, and they can be used as target design spectra, for example, conditional mean spectrum (CMS) and eta‐based conditional mean spectrum (ECMS) . Another approach is that of the generalized conditional intensity measure (GCIM), which has been proposed for the selection of ground motions for any form of seismic response analysis .…”

Section: Introductionmentioning

confidence: 99%

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The conditional mean spectra by disaggregating the eta spectral shape indicator

Mohandesi

Azarbakht

Ghafory‐Ashtiany

2019

Structural Design Tall Build

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Conditional spectra are a recent development in this field, which utilizes the advantages of spectral shape indicators, for example, epsilon and eta. The application of an eta indicator in conditional spectra calculations depends mainly on calculating the peak ground velocity epsilon, data about which are not readily available in the current literature. This issue has been solved by linear regression between the conventional epsilon and the peak ground velocity epsilon. However, not enough attention has been paid in the literature to the disaggregation of the eta indicator. For this reason, the disaggregation of seismic hazard based on the use of an eta indicator has been investigated in this paper, based on a simplified linear seismic source. The obtained results were compared with the available approach in the literature, which shows that this refinement has a meaningful effect on the conditional spectra specifically in the short period range. Furthermore, eta-based conditional spectra are used at different hazard levels to select ground-motion records. A threestoreyed building is then analysed, and the corresponding annual probability of failure is calculated based on the full dataset as well as on the records, which were selected based on conditional spectra.

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E-CMS: A new design spectrum for nuclear structures in high levels of seismic hazard

Cited by 8 publications

References 15 publications

Efficiency of alternative intensity measures for the seismic assessment of monolithic free-standing columns

Efficiency of alternative intensity measures for the seismic assessment of monolithic free-standing columns

The dependence of conditional spectra on the choice of target periods

The conditional mean spectra by disaggregating the eta spectral shape indicator

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