Hindawi Publishing Corporation
Mathematical Problems in Engineering
Volume 2013, Article ID 679026, 9 pages
http://dx.doi.org/10.1155/2013/679026
Research Article
A New Spectral Shape-Based Record Selection Approach Using
and Genetic Algorithms
Edén Bojórquez,
1
Alfredo Reyes-Salazar,
1
Sonia E. Ruiz,
2
and Juan Bojórquez
2
1
Facultad de Ingenier´ ıa, Universidad Aut´ onoma de Sinaloa, Ciudad Universitaria, Calzada de las Am´ ericas y
Boulevard Universitarios S/N, 80040 Culiac´ an Rosales, SIN, Mexico
2
Coordinaci´ on de Mec´ anica Aplicada, Instituto de Ingenier´ ıa, Universidad Nacional Aut´ onoma de M´ exico,
Ciudad Universitaria, 04510 Coyoac´ an, DF, Mexico
Correspondence should be addressed to Alfredo Reyes-Salazar; reyes@uas.edu.mx
Received 27 September 2012; Revised 13 December 2012; Accepted 13 December 2012
Academic Editor: Wei-Chiang Hong
Copyright © 2013 Ed´ en Boj´ orquez et al. Tis is an open access article distributed under the Creative Commons Attribution License,
which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
With the aim to improve code-based real records selection criteria, an approach inspired in a parameter proxy of spectral shape,
named
, is analyzed. Te procedure is based on several objectives aimed to minimize the record-to-record variability of the
ground motions selected for seismic structural assessment. In order to select the best ground motion set of records to be used as
an input for nonlinear dynamic analysis, an optimization approach is applied using genetic algorithms focuse on fnding the set
of records more compatible with a target spectrum and target
values. Te results of the new
-based approach suggest that
the real accelerograms obtained with this procedure, reduce the scatter of the response spectra as compared with the traditional
approach; furthermore, the mean spectrum of the set of records is very similar to the target seismic design spectrum in the range
of interest periods, and at the same time, similar
values are obtained for the selected records and the target spectrum.
1. Introduction
Currently, it has been thoroughly discussed in the literature
that the selection of appropriate earthquake ground motion
record sets to be used as input for nonlinear dynamic analysis
and several methodologies have been proposed to reduce the
number of ground motion records needed for the reliable
prediction of seismic response of structures [1–3]. Buildings
design codes as FEMA 450 [4] and Eurocode 8 (EC8) [5]
suggest the use of seven ground motion records as input for
seismic performance of structures to consider the average
values of the structural responses. In particular, the seismic
design codes guidelines are based on the use of records
matching the pseudo-acceleration spectral shape in a range
of periods as the main one among other criteria. Because
of the known high variability of nonlinear seismic response
of structures, the average spectra of the set of records must
be as close as possible to the seismic design code spectrum
in order to estimate the structural response with relatively
high confdence given only seven analyses. To this aim, it
is important to defne ground motion intensity measures
representative of the spectral shape, which may help in
record selection driven by a target spectrum due to the
ability of this as predictor of nonlinear structural response
[6–12]. In fact, to improve the efciency in the prediction
of structural response, recently, vector-valued and scalar
ground motion intensity measures based on a parameter
to characterize the spectral shape named
have been
proposed by Boj´ orquez and Iervolino [10]. Tis parameter
has resulted very efective to feature the spectral shape even
for diferent types of earthquake ground motion records and
to predict the nonlinear structural response in terms of peak
and seismic energy demands. Moreover, it can predict the
structural failure in term of peak and energy demand with
good accuracy [12].
Motivated by the purpose to improve the strategies for
code-based records selection inspired in the spectral shape,
a procedure established for
is proposed in the study. To
this aim, a total of 1024 earthquake ground motions with
diferent characteristics taken from the NGA database and