Search for: strong-motion
Article Asian Journal of Civil Engineering ; Volume 13, Issue 5 , 2012 , Pages 647-657 ; 15630854 (ISSN) ; Estekanchi, H. E ; Sharif University of Technology
Endurance Time (ET) method is a dynamic analysis procedure using intensifying accelerograms which can be used to assess the structural performance at different excitation levels. In generation process of current ET accelerograms, the compatibility between acceleration spectrum produced by the ET accelerograms and acceleration spectrum associated with the real ground motions is applied, whereas the duration consistency is not directly considered. It is generally accepted that the strong-motion duration can strongly influence the response of structures which have stiffness or strength degrading characteristics. In this study, the number of cycles that a structure should resist due to a ground...
Application of base-line correction methods to obtain permanent displacements of a near-source ground motion: The 2003 bam earthquake, Article Journal of Earthquake Engineering ; Volume 13, Issue 3 , 2009 , Pages 313-327 ; 13632469 (ISSN) ; Khatam, H ; Farahi Jahromi, H ; Sharif University of Technology
In this article, two base-line correction methods for correcting the near-source strong motions were studied on the near-source recording of the 2003, Bam earthquake. To obtain permanent ground displacements at Bam station, two methods were applied with some modifications and without using any kind of filtering. Even though it is difficult to calculate true permanent displacements from data attained by present accelerograms, the results of this study show that the rational limit of permanent ground displacements can be successfully achieved by rational choosing of effective parameters. In addition, it is observed that some pre-processing steps suggested in literature have no considerable...
Article Scientia Iranica ; Vol. 20, issue. 4 , 2014 , p. 1085-1093 ; 10263098 ; Estekanchi, H. E ; Sharif University of Technology
The Endurance Time (ET) method is a dynamic analysis procedure using intensifying excitation. The ET excitation functions are generated so that structural performance can be assessed at different excitation levels in a single response history analysis. ET accelerograms, which have been generated so far, possess response spectra consistency; this means that the duration consistency has not been directly considered. Strong-motion duration can influence the response of structures which have stiffness or strength degrading characteristics. In this paper, several well-known strong-motion duration definitions are studied in the context of the ET method. Ground motions are scaled to spectral...
Estimating the seismological source parameters of the 2006 Silakhor earthquake, Iran, using a Genetic Algorithm, Article 9th International Conference on Computational Structures Technology, CST 2008, Athens, 2 September 2008 through 5 September 2008 ; Volume 88 , 2008 ; 17593433 (ISSN); 9781905088232 (ISBN) ; Abbasnia, R ; Eslamian, Y ; Bozorgnasab, M ; Nicknam, A ; Sharif University of Technology
Civil-Comp Press 2008
The main objective of this article is to estimate the seismological source parameters of Silakhor earthquake which happened on March 31, 2006, in the southern part of Iran. The Empirical Green's Function approach was used for simulating the main shock and the well known Genetic Algorithm was utilized for modifying the seismological source parameters. The Kostrov slip function was adopted in the model due to its ability in more accurately modeling the rupture process. The selected station was sufficiently far away from the causative source so that the near source problems would not effect on the simulated time series. The GA process compares the elastic response spectra with 5% damping ratio,...
Article Bulletin of Earthquake Engineering ; Volume 17, Issue 11 , 2019 , Pages 5987-6008 ; 1570761X (ISSN) ; Harati, M ; Ashoori Barmchi, M ; Estekanchi, H. E ; Sharif University of Technology
Springer Netherlands 2019
This study proposes a response-based parameter for strong motion duration which is computed for structures and is the total time they are nonlinear during an earthquake. Correlation between structural response and duration for structures, subjected to a set of spectrum matched ground motions, is employed to examine the efficiency of the proposed method. The spectral matching procedure ensures that the influence of amplitude and frequency content of motions on structural response variability is significantly removed. Four concrete building type systems are studied and correlation coefficients of structural response with the proposed duration definition are examined. Comparison of the proposed...
Article Engineering Structures ; Volume 223, Issue 15 , November , 2020 ; Harati, M ; Darzi, A ; Estekanchi, H. E ; Sharif University of Technology
Elsevier Ltd 2020
This study proposes a new approach to incorporate motion duration in incremental dynamic assessments. In the proposed methodology, at each intensity level, a simulation-based approach which is verified with actual data is employed to determine the median duration and the median acceleration spectra of ground motions expected to occur at the site. Afterward, at each intensity level, artificial or spectrally matched motions are produced based on the median acceleration spectra and the median duration, indicating that different intensity levels are directly covered by the generated artificial or adjusted motions rather than just scaling up and down a set of recorded ground motions. In the...
Minimizing the uncertainties of seismological-geotechnical source parameters using a genetic algorithm approach, Article 9th International Conference on Computational Structures Technology, CST 2008, Athens, 2 September 2008 through 5 September 2008 ; Volume 88 , 2008 ; 17593433 (ISSN); 9781905088232 (ISBN) ; Abbasnia, R ; Bozorgnasab, M ; Eslamian, Y ; Nicknam, A ; Sharif University of Technology
Civil-Comp Press 2008
The main purpose of this article is to estimate the seismological source parameters of the December 26, 2003, Bam earthquake Mw6.5 (Iran). The selected station is far away from the causative fault so that the synthesized ground motion would not be influenced by near source problems such as directivity effects. The well known Empirical Green's Functions (EGF) is used to synthesize the three components of main shock. The Kostrov slip model describing the entire rupture process was incorporated in the model. A generic algorithm (GA) technique is proposed for minimizing the differences between the synthesized time series and those of observed data. The estimated time series were validated by...
Article Soil Dynamics and Earthquake Engineering ; Volume 27, Issue 2 , 2007 , Pages 99-110 ; 02677261 (ISSN) ; Jahankhah, H ; Sharif University of Technology
The effect of soil conditions on strength reduction factors (SRFs) is investigated. Both site effect and soil-structure interaction (SSI) effect are considered in the study with special emphasis on the latter effect. The structure is modeled as an elasto-plastic single degree of freedom (SDOF) system, whereas the underlying soil is considered as a homogeneous half-space. The half-space is also replaced by a simplified 3DOF system, based on the concept of Cone Models. The whole 4DOF model is then analyzed under a total of 54 strong motions recorded on different soil types. A parametric study is done for a wide range of non-dimensional parameters, which completely define the problem. It is...
M.Sc. Thesis Sharif University of Technology ; Esmaeil Pourestekanchi, Homayoon
Endurance Time Method (ET) is a dynamic analysis in which structures are subjected to intensifying accelerograms and performance of them are assessed based on their response at different excitation levels. Duration consistency of current ET accelerograms has not been directly considered. Strong motion duration can strongly influence the response of structures and foundations especially when they encounter degrading characteristics in their materials. In this study, duration related properties of ET accelerograms and ground motions are compared. These properties consist of strong motion duration, cycles number of motion and number of nonlinear cycles which a structure should sustain when it...
Article Earthquake Engineering and Structural Dynamics ; Volume 42, Issue 8 , 2013 , Pages 1221-1242 ; 00988847 (ISSN) ; Abazarsa, F ; Ghannad, M. A ; Taciroglu, E ; Sharif University of Technology
Dynamic characteristics of structures - viz. natural frequencies, damping ratios, and mode shapes - are central to earthquake-resistant design. These values identified from field measurements are useful for model validation and health-monitoring. Most system identification methods require input excitations motions to be measured and the structural response; however, the true input motions are seldom recordable. For example, when soil-structure interaction effects are non-negligible, neither the free-field motions nor the recorded responses of the foundations may be assumed as 'input'. Even in the absence of soil-structure interaction, in many instances, the foundation responses are not...