International Institute of Earthquake Engineering and Seismology

Tehran, Iran

International Institute of Earthquake Engineering and Seismology

Tehran, Iran

International Institute of Earthquake Engineering and Seismology , founded by Mohsen Ghafory-Ashtiany, is an international earthquake engineering and seismology institute based in Iran. It was established as a result of the 24th UNESCO General Conference Resolution DR/250 under Iranian government approval in 1989. It was founded as an independent institute within the Iran’s Ministry of Science, Research and Technology.Mohsen Ghafory-Ashtiany distinguished professor of earthquake engineering and risk management at International Institute of Earthquake Engineering and seismology which was founded by him in 1989, is Chief Editor of JSEE and IDRiM Journals; author of more than 140 papers and 3 books in the field of earthquake engineering, seismic hazard and risk analysis, risk management and planning. Ashtiany is the Director and member of the Executive committee of International Association of Earthquake engineering , Chairman of Earthquake Hazard, Risk and Strong Ground Motion Commission of IASPEI, member of UN-ISDR Scientific and Technical commission, Director and member of board of World Seismic Safety Initiative, member of Global Earthquake Risk Model Project; Member of Geo-Hazard Initiative, Member of GSHAP, Member of Global Risk Forum-Davos, and many other scientific communities. Ashtiany was born in Tehran, Iran in 1957 and graduated from Va. Tech in 1983 with honor, and is resident of US.On its establishment, the IIEES drew up a seismic code in an attempt to improve the infrastructural response to earthquakes and seismic activity in the country. Its primary objective is to reduce the risk of seismic activity on buildings and roads and provide mitigation measures both in Iran and the region.The institute is responsible for much of the research and education in this field by conducting research and providing education and knowledge in seismotectonic studies, seismology and earthquake engineering. In addition conducts research and educates in risk management and generating possibilities for an effective earthquake response strategy. The IIEES is composed of the following research Centers: Seismology, Geotechnical Earthquake Engineering, Structural Earthquake Engineering, Risk Management; National center for Earthquake Prediction, and Graduate School, Public Education and Information Division. Wikipedia.

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Mohammadi M.,International Institute of Earthquake Engineering and Seismology
Proceedings of the Institution of Civil Engineers: Structures and Buildings | Year: 2017

An engineered infilled structural building frame with adjustable strength is proposed. The infill wall has a frictional sliding fuse at mid-height, which can be regulated for a certain sliding strength. Previous experimental and analytical studies have shown that greater fuse strength leads to higher strength but lower ductility for the infilled frame. This paper discusses optimising the fused infill panel. The modification factors and expected strengths of infills with different fuse strengths were calculated and compared. To complement the study on fused infill panels, the influences of an opening were investigated experimentally. Two one-third scale single-storey single-bay concrete infilled steel frames having a frictional sliding fuse were tested by displacement-controlled cyclic loading. The specimen with a door opening at the centre was compared with the specimen with solid infill. © 2017, Thomas Telford Services Ltd. All rights reserved.


Mohammadi M.,International Institute of Earthquake Engineering and Seismology
International Journal of Civil Engineering | Year: 2017

Sliding foundation is a technique to suppress seismic loads applied to structures. There are many studies showing that sliding foundations are efficient especially for low rise buildings; however, most of them have ignored the effects of vertical components of the earthquake records on the behavior of such bases. This paper focuses on influences of sliding foundations on seismic behavior of low rise buildings, for real cases. For this purpose, vertical component of earthquakes is considered as well as inherent properties of foundation material such as coefficient of restitution (COR). Furthermore, variation of friction coefficient during the earthquake is considered. COR is utilized to consider bouncing of the structure after separation of the foundation, occurred for extreme downward vertical accelerations (greater than gravitational acceleration). Variation of friction coefficient is considered based on a new study, showing that the coefficient of friction depends on instantaneous amplitude and frequency of the vertical excitation. The obtained results show that vertical component of earthquake affects the behavior of the sliding base substantially. It is also demonstrated that providing material for the sliding base with higher COR is advantageous in decreasing structural acceleration response. Furthermore, the coefficient of friction is really lower than the regularly assumed values and, therefore, leads to smaller structural acceleration response but mostly greater residual displacements. © 2017, Iran University of Science and Technology.


Mohammadi M.,International Institute of Earthquake Engineering and Seismology
International Journal of Civil Engineering | Year: 2017

Most rehabilitation codes have a special part for regular masonry infill panels. However, they are completely silent for infills improved by concrete covers, probably for the lack of sufficient experimental test data. Shotcreting one side or both sides of the existing infills is one of the best methods to improve structural seismic behavior. Therefore, this paper focuses on the ultimate strengths and modification factors of this type of infill panels, based on the existing experimental data of the literature. The existing formula of the codes is improved to estimate ultimate strength of such infill panels. Furthermore, modification factors of primary and rehabilitated specimens are calculated and compared. In this regard, envelopes of the load–displacement behavior of the specimens are applied, as well. It is shown that envelops give more conservative values for the m-factor, compared with the standard backbone curves. It is shown that modification factor of masonry infill panels is decreased when rehabilitated by concrete covers; however, for clay tile infills, it remains almost unchanged. © 2017, Iran University of Science and Technology.


Mokhtari M.,International Institute of Earthquake Engineering and Seismology
Natural Hazards | Year: 2010

Iran has long been known as one of the most seismically active areas of the world, and it frequently suffers destructive and catastrophic earthquakes that cause heavy loss of human life and widespread damage. The Alborz region in the northern part of Iran is an active EW trending mountain belt of 100 km wide and 600 km long. The Alborz range is bounded by the Talesh Mountains to the west and the Kopet Dagh Mountains to the east and consists of several sedimentary and volcanic layers of Cambrian to Eocene ages that were deformed during the late Cenozoic collision. Several active faults affect the central Alborz. The main active faults are the North Tehran and Mosha faults. The Mosha fault is one of the major active faults in the central Alborz as shown by its strong historical seismicity and its clear morphological signature. Situated in the vicinity of Tehran city, this 150-km-long N100° E trending fault represents an important potential seismic source. For earthquake monitoring and possible future prediction/precursory purposes, a test site has been established in the Alborz mountain region. The proximity to the capital of Iran with its high population density, low frequency but high magnitude earthquake occurrence, and active faults with their historical earthquake events have been considered as the main criteria for this selection. In addition, within the test site, there are hot springs and deep water wells that can be used for physico-chemical and radon gas analysis for earthquake precursory studies. The present activities include magnetic measurements; application of methodology for identification of seismogenic nodes for earthquakes of M ≥ 6.0 in the Alborz region developed by International Institute of Earthquake Prediction Theory and Mathematical Geophysics, IIEPT RAS, Russian Academy of Science, Moscow (IIEPT&MG RAS); a feasibility study using a dense seismic network for identification of future locations of seismic monitoring stations and application of short-term prediction of medium- and large-size earthquakes is based on Markov and extended self-similarity analysis of seismic data. The establishment of the test site is ongoing, and the methodology has been selected based on the IASPEI evaluation report on the most important precursors with installation of (i) a local dense seismic network consisting of 25 short-period seismometers, (ii) a GPS network consisting of eight instruments with 70 stations, (iii) magnetic network with four instruments, and (iv) radon gas and a physico-chemical study on the springs and deep water wells. © Springer Science+Business Media B.V. 2009.


Goudarzi M.A.,International Institute of Earthquake Engineering and Seismology
Journal of Pressure Vessel Technology, Transactions of the ASME | Year: 2013

Second mode sloshing motion induces the vertical out-of-plane deformation of deck plate in single deck floating roof (FR) cylindrical storage tanks. This vertical deformation tends to shrink the deck plate in horizontal direction, causing elliptical deformation of pontoon. In order to evaluate seismic stress caused by the second sloshing mode, the relation between out-of-plane vertical deformation of deck plate and the radial shrinkage of pontoon is required. In this study, a simple analytical approach is proposed for calculating the shrinkage of the pontoon. The numerical analysis is also performed for five tanks with various dimensions to assess the effectiveness of introduced new method. The accuracy of proposed formulation is confirmed by comparing its results with the results of both numerical analysis and available experimental measurements. Despite existing empirical formula, geometric characteristics of considered tanks are involved in proposed formulation and it is shown that final relationship could be utilized for various ranges of tank dimensions without scaling or unit limitation. It is also found from the results of numerical analysis that the dynamic characteristics of sloshing modes are not considerably affected by the presence of floating roof. © 2013 by ASME.


Daneshmand A.,International Institute of Earthquake Engineering and Seismology | Hosseini Hashemi B.,International Institute of Earthquake Engineering and Seismology
Journal of Constructional Steel Research | Year: 2012

Recent researches about the performance of eccentrically braced frames have shown that some of the intermediate-length links do not meet the requirements of AISC2005. Further investigations on the current AISC 2005 provisions and also assessing the effect of involved parameters on the behavior of this type of links have been carried out in this research. Moreover, to cover the shortages of previous researches conducted on the performance of long links compared to short ones, some flexural links are also put into the study. By analyzing the links made of European-standard rolled shape sections, validity of the provisions for these types of links, which fewer investigations about them are available, is also examined. The Finite element analysis employing 3D solid elements is implemented to model a total of 68 links. Results of the study imply some design suggestions for these types of links. Also, the slenderness ratio of the web as well as the specification of the stiffeners is discerned as important parameters impacting on the performance of the intermediate links. © 2011 Elsevier Ltd. All rights reserved.


Hosseini Hashemi B.,International Institute of Earthquake Engineering and Seismology | Jafari M.A.,Niroo Research Institute
Journal of Constructional Steel Research | Year: 2012

This research was performed to evaluate two analytical methods for predicting the compressive strength of batten columns. Batten columns were subjected to pure axial compression, and the compressive strength was measured. The analytical methods used included the well-known Ayrton-Perry and ultimate strength curve methods to calculate the compressive strength of imperfect solid web columns, but their validity has not yet been studied experimentally on built-up columns. The geometrical parameters considered included the batten plate spacing and dimensions and the distance between the two longitudinal chords. The results show that the analytical methods were generally valid for the prediction of the compressive strength in batten columns and solid web columns. Using the average results of the Ayrton-Perry and ultimate strength curve methods leads to the best prediction of the column compressive strength. It was also shown that the initial imperfections in the batten columns could have a more important effect than the geometrical specifications on the value of compressive strength. © 2011 Elsevier Ltd.


Zafarani H.,International Institute of Earthquake Engineering and Seismology | Soghrat M.,Tarbiat Modares University
Bulletin of the Seismological Society of America | Year: 2012

Physically based ground-motion prediction equations for soil and rock sites in the Zagros region have been developed based on the specific barrier model (SBM) used within the context of the stochastic model. Instead of direct timedomain simulation, random vibration theory was used to estimate measures of peak motion in terms of the pseudospectral velocity of anelastic harmonic oscillator with 5% viscous damping. To avoid the uncertainties, calibration of the source model uses a database of carefully selected strong motion data without ambiguity about the site condition. Therefore, only rock sites are selected for determining source parameters. Also, to avoid any inconsistencies caused by magnitude conversion formulas, we restricted the dataset only to events with available moment magnitudes. Regression analysis is performed using the random effects model that considers both interevent and intraevent variabilities to effectively deal with the problem of an unequal number of records from different earthquakes. No sign of self-similarity breakdown is observed between the source radius and its seismic moment. The local and global stress drops derived for the Zagros region (39 and 116 bars, respectively) are more consistent with the values obtained by other authors for an interplate regime than the values for an intraplate region. However, from the viewpoint of source heterogeneity (as the ratio of the stress drops is an indicator of the complexity of the source and heterogeneity of slip on the fault) the Zagros events, which have a stress-drop ratio of about three are more homogeneous than other interplate events. Stochastic simulations are then implemented to predict peak ground motion and response spectra parameters for rock and soil site conditions.


Ali Goudarzi M.,International Institute of Earthquake Engineering and Seismology | Reza Sabbagh-Yazdi S.,University of Tehran
Soil Dynamics and Earthquake Engineering | Year: 2012

Nonlinear behavior of liquid sloshing inside a partially filled rectangular tank is investigated. The nonlinearity in the numerical modeling of the liquid sloshing originates from the nonlinear terms of the governing equations of the fluid flow and the liquid free surface motion as a not known boundary condition. The numerical simulations are performed for both linear and nonlinear conditions. The computed results using linear conditions are compared with readily available exact solution. In order to verify the results of the nonlinear numerical solution, a series of the shaking table tests on rectangular tank were conducted. Having verified linear and nonlinear numerical models, they are used for computation of near wall sloshing height at a series of real scale tanks (with various dimensions) under the both harmonic and earthquake base excitation. Finally, the nonlinear effects on liquid sloshing modeling are discussed and the practical limitations of the linear solution in evaluating the response of seismically excited liquids are also addressed. © 2012 Elsevier Ltd.


Alavi E.,International Institute of Earthquake Engineering and Seismology | Nateghi F.,International Institute of Earthquake Engineering and Seismology
Journal of Constructional Steel Research | Year: 2013

One of the advantages of Steel Plate Shear Walls (SPSWs) is the easiness of openings application in infill plate. The openings are sometimes required for passing utilities, architectural purposes, and/or structural reasons. However, the recent researches on perforated steel plate shear walls have shown that the shear strength and stiffness of an un-stiffened steel shear wall decrease due to perforation of the infill plate. Hence, this paper presents a special combination of diagonal stiffeners with a central perforation. The seismic behavior of the new system is experimentally investigated and compared to the solid infill plate models. Experimental testing is performed on three scaled single-story SPSW specimens under cyclic quasi-static loading. One of the specimens is un-stiffened and the two others are diagonally stiffened, which in one of them, a circular opening with the diameter of depth of the panel is cutout from the wall center. It is observed that by means of the proposed stiffening method the shear strength of the perforated shear walls is achieved close to the un-stiffened wall with the solid panel, and the seismic behavior of the system is considerably improved. Test results show that the ductility ratio of the specially perforated specimen is about 14% greater than the un-stiffened specimen. A formula is developed and verified for the estimation of the shear strength of a perforated and diagonally stiffened SPSW. There are good agreements between the experimental outcomes and the theoretical predictions. © 2013 Elsevier Ltd.

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