Reliable estimation of the mean annual frequency of collapse by considering ground motion spectral shape effects

Bull Earthquake Eng (2015) 13:777797 DOI 10.1007/s10518-014-9651-8

ORIGINAL RESEARCH PAPER

Reliable estimation of the mean annual frequencyof collapse by considering ground motion spectral shape effects

Alireza Azarbakht Mohamadreza Shahri

Mehdi Mousavi

Received: 10 August 2013 / Accepted: 28 June 2014 / Published online: 12 July 2014 Springer Science+Business Media Dordrecht 2014

Abstract Ground motion record (GMR) selection is an important issue in the nonlinear dynamic analysis procedure. Most of the current design codes recommend to use GMRs in which their mean spectrum be matched to a design spectrum e.g. uniform hazard spectrum. However recent research results have shown that the code methodology is neither robust nor realistic. On the other hand, GMR selection, based on spectral shape, is recently proposed in order to deal with this problem. and are two powerful spectral shape indicators which are used for GMR selection purposes. A comparison between and was made in order to access their capability to predict the linear spectral shape and the structural nonlinear response. The -based conditional mean spectrum (E-CMS), which has been recently emerged as a new design spectrum, was also investigated in this study. The E-CMS formulation format is fully compatible with the existing CMS denition which makes E-CMS quite easy to be implemented. The resulted E-CMS was used as a target spectrum for the record selection. Analysis of a set of multi degree of freedom systems shows that the mean annual frequency of collapse is achievable, with more reliability, based on the new emerged indicator. Therefore, the bias is decreased by employing the concept into the record selection procedure. The bias reduction is more signicant in higher hazard levels and in the case of structures with low natural periods or with signicant higher mode effects.

Keywords Uniform hazard spectrum -Based conditional mean spectrum Indicator

Indicator Ground motion record selection Seismic hazard

1 Introduction

The Pacic Earthquake Engineering Research (PEER) centre framework is a popular methodology in order to estimate the mean annual frequency (MAF) of exceedance a particular Limit

A. Azarbakht (B) M. Shahri M. Mousavi

Department of Civil Engineering, Faculty of Engineering, Arak University, P.O. Box 38156-88359, Arak, Irane-mail: [email protected]

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Fig. 1 Median predicted spectrum, UHS for 2% probability...