Search for: earthquake-mechanism
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    Study on dynamic and mechanical characteristics of carbon fiber- and polyamide fiber-reinforced seismic isolators

    , Article Materials and Structures/Materiaux et Constructions ; Volume 47, Issue 3 , March , 2014 , Pages 447-457 ; ISSN: 13595997 Bakhshi, A ; Jafari, M. H ; Valadoust Tabrizi, V ; Sharif University of Technology
    Seismic isolators are used to decrease the energy and forces of earthquakes. The weight of conventional steel-reinforced elastomeric isolators (SREIs) is high, mostly due to the use of multiple steel shim plates. On the contrary, the damping ratio of SREIs is relatively low. Accordingly, this research utilizes a new approach in which the steel shim plates are replaced by carbon and polyamide fibers. This study attempts to obtain the dynamic and mechanical properties of such carbon fiber- and polyamide fiber-reinforced elastomeric isolators, in comparison with SREIs. In this work, a number of specimens were initially designed and manufactured. Afterwards, compression and cyclic shear tests... 

    A multi-objective robust optimization model for logistics planning in the earthquake response phase

    , Article Transportation Research Part E: Logistics and Transportation Review ; Volume 49, Issue 1 , 2013 , Pages 217-249 ; 13665545 (ISSN) Najafi, M ; Eshghi, K ; Dullaert, W ; Sharif University of Technology
    Usually, resources are short in supply when earthquakes occur. In such emergency situations, disaster relief organizations must use these scarce resources efficiently to achieve the best possible emergency relief. This paper therefore proposes a multi-objective, multi-mode, multi-commodity, and multi-period stochastic model to manage the logistics of both commodities and injured people in the earthquake response. Also, a robust approach is developed and used to make sure that the distribution plan performs well under the various situations that can follow an earthquake. Afterwards, it proposes a solution methodology according to hierarchical objective functions and uses it to illustrate the... 

    Endurance time method for multi-component analysis of steel elastic moment frames

    , Article Scientia Iranica ; Volume 18, Issue 2 A , 2011 , Pages 139-149 ; 10263098 (ISSN) Valamanesh, V ; Estekanchi, H. E ; Sharif University of Technology
    The Endurance Time (ET) method is a time history-based dynamic analysis procedure which uses special intensifying acceleration functions for evaluation of the seismic response of structures. One of the potential applications of the ET method is in the three-dimensional analysis of buildings under multidirectional excitations. In this paper, considering horizontal components of excitation, an algorithm for the multi-component analysis of building structures by the ET method is proposed, and results of the ET method for various steel moment frames with 1 to 7 stories are compared with results from time history analysis with real earthquakes. Results show that based on recommendations of... 

    The exact and approximate conditional spectra in the multi-seismic-sources regions

    , Article Soil Dynamics and Earthquake Engineering ; Volume 39 , August , 2012 , Pages 61-77 ; 02677261 (ISSN) Ebrahimian, H ; Azarbakht, A ; Tabandeh, A ; Akbar Golafshani, A ; Sharif University of Technology
    Elsevier  2012
    The exact and two approximate conditional spectra are compared in this manuscript as a target spectrum for the purpose of ground motion selection. The considered site is a real offshore site located at South Pars Gas Field in the Persian Gulf region. This case study site is influenced by four major seismic area sources in which the deaggregation results confirm that many comparable seismic scenarios can be taken into account. Therefore, an alternative to the conventional approximate conditional spectrum is proposed that has a small deviation from the exact solution. In addition, the use of different conditioning status of the probabilistic seismic hazard deaggregation (i.e., occurrence...