Seismic Hazard Zoning in Iran: A State-of-the-Art on the Studies during Four Decades
Mehdi
Zare
International Institute of Earthquake Engineering and Seismology (IIEES)
author
text
article
2017
eng
This is a state-of-the-art paper on the seismic hazard zoning studies performed in Iran since the mid-1970s to 2015. Reliable seismic hazard studies depend on having a robust earthquake catalog, good knowledge of tectonic conditions and relevant attenuation models applied for the hazard calculations. The better input for hazard analysis results in the more reliable parameters and seismic hazard assessments. The first generations of seismic hazard zoning maps in Iran were developed based on the deterministic approaches for calculation of maximum intensities (e.g. [1] and [2]). In 1982, Bozorgnia and Mohajer-Ashjai [3] published the first comprehensive probabilistic hazard assessment for major cities of Iran. The first PGAzoningmap for the greater Tehran region was also published by Berberian et al. [4]. The next generations of seismic hazard zoning studies were carried out for dam sites, which were under construction during the 1980s and 1990s in Iran. A seismic hazard zoning map of Iran for the "design earthquake" (so called 475 years of return period), was published in 1999 as an attachment to the Iranian seismic code for buildings (Standard No. 2800). In the recent years, a number of detailed hazard zoning maps for the greater cities and specific industrial sites have also been presented. The defined spectral attenuation equations for Iran (e.g. [5-17]) can be used for producing spectral zoning maps. These maps can be developed using region specific ground-motion prediction equations by considering various ground-motion parameters that involve spectral acceleration, displacement and peak groundmotion values. Therefore, there are still ongoing attempts to develop the probabilistic seismic zoning maps for Iran. In this paper, the seismic hazard zoningmaps of Iran developed in the last 40 years are investigated. It is tried to depict the development history of the seismic hazard zoning studies for Iran, which have been started since the mid-1970s. Briefly, the trend of such studies was started by the application of deterministic approaches for estimation of intensity and then was continued using probabilistic approaches. Future studies on the seismic hazard zoning in Iran seems to cover newapproaches such as the realistic acceleration and the neo-deterministic approaches, time-dependent mapping, intelligent updating of hazard maps as well as the development of site-specific hazard analysis based on the development of more detailed data.
Journal of Seismology and Earthquake Engineering
International Institute of Earthquake Engineering and Seismology
1735-1669
19
v.
2
no.
2017
71
101
http://www.jsee.ir/article_240762_087b6fe5462b61c5ff5c62fe3eb70f09.pdf
Implementation of Hierarchical Tree Structure in Fast Multipole Method in 2-D Seismic Elastic Domain
Mohammad
Saffar
International Institute of Earthquake Engineering and Seismology (IIEES)
author
Mohsen
Kamalian
International Institute of Earthquake Engineering and Seismology (IIEES)
author
text
article
2017
eng
A numerical boundary element, as an appurtenance of integral equation method, has some useful characteristics that facilitate the solutions of numerical equations, but asymmetrical and sparse structure of formed stiffness matrix in large-scale boundary element method related to high degree of freedom problems make it unpractical, especially in seismic analysis of large-scale surface topographies with irregularities. Nowadays, fast algorithms such as fast multi-pole method present new media in numerical solutions with the aim of revolutionary changes in geometric definitions. In contrary with the usual node-to-node or element-toelement interconnection implementation, the cell-to-cell relation along hierarchy tree structure is applied. In most papers, the fast algorithm uses a two-level hierarchical tree structure as a part of algorithm internally without detail illustration. Therefore, a comprehensive detail of hierarchical tree structure is requested. In this paper, a multi-level (level definition is dynamic) hierarchical tree structure is presented with graphical theme and examples. This paper presents the relation between conventional boundary element method geometric structure with hierarchical tree model, and later, explains the method along with its abilities and limitations.
Journal of Seismology and Earthquake Engineering
International Institute of Earthquake Engineering and Seismology
1735-1669
19
v.
2
no.
2017
103
112
http://www.jsee.ir/article_240757_5340cd23539b727b3308796cd58b45b1.pdf
Out-of-Plane Behavior of Masonry Infill Walls
Farhad
Akhoundi
Tabriz Islamic Art University
author
Graça
Vasconcelos
ISISE, University of Minho
author
Paulo
Lourenço
ISISE, University of Minho
author
text
article
2017
eng
Past earthquakes have highlighted the vulnerability of masonry infills in the out-of-plane direction. To investigate this vulnerability, it is necessary to test some samples of infills in the out-of-plane direction taking into consideration that the main problem in the simulation of the out-of-plane response is their test setup and calculation of out-of-plane force applied to the infills. One can suggest that multiplying the pressure inside the airbag times its effective area (area of the airbag in full contact with infill) can lead to calculation of the out-of-plane force; but in this paper, it is concluded that the distance between the reaction wall keeping the airbag and the infill affects the effective area of the airbag. When the distance between the reaction walls and the masonry infill wall is smaller, the effective area is closer to the nominal area of the airbag. The effective contact area of the airbag is calculated by dividing the load measured in load cells by the pressure inside the airbag. Based on this result, it is also recommended to use load cells in the test setup to measure the out-of-plane force instead of its calculation by the pressure inside the airbag. After the installation of the out-of-plane test setup, one specimen representing the contemporary construction typology in North of Portugal was tested. In order to investigate its out-of-plane behavior, quasi-static testing was performed on a masonry infill built inside a reinforced concrete frame by means of an airbag system to apply the uniform out-of-plane load to each component of the infill. The main advantage of this testing setup is that the out-of-plane loading can be applied more uniformly in the walls, contrarily to point load configuration. The test was performed under displacement control by selecting the mid-point of the infill as control point. Input and output air in the airbag was controlled by using a software to apply a specific displacement in the control point of the infill wall. Four load cells were attached to the reaction frame to measure the out-of-plane force. Deformation and crack pattern of the infill confirm the formation of arching mechanism and two-way bending of the masonry infill. Until collapse of the horizontal interface between infill and upper beam in RC frame, the infill bends in two directions. However, the failure of that interface that is known as weakest interface due to difficulties in filling the mortar between bricks of last row and upper beam results in the crack opening trough a well-defined path and the consequent collapse of the infill. It is also investigated that the collapse of the infill was happened suddenly unlike the specimens tested by [1]. This is related to the presence of higher axial force on top of the columns in [1] that resulted in formation of a two-way arching mechanism supported on four sides. Besides, it seems that the presence of higher axial force on top of the columns can compensate the defects of upper interface.
Journal of Seismology and Earthquake Engineering
International Institute of Earthquake Engineering and Seismology
1735-1669
19
v.
2
no.
2017
113
122
http://www.jsee.ir/article_240758_138b50f9f06fd2539f46ae3f6c4765b1.pdf
Ranking of GMPEs for Seismic Hazard Analysis in Iran Using LH, LLH and EDR Approaches
Mohammad
Fallah Tafti
International Institute of Earthquake Engineering and Seismology (IIEES)
author
Kambod
Amini Hosseini
International Institute of Earthquake Engineering and Seismology (IIEES)
author
Erfan
Firouzi
International Institute of Earthquake Engineering and Seismology (IIEES), Tehran, Iran
author
Babak
Mansouri
International Institute of Earthquake Engineering and Seismology (IIEES)
author
Anooshiravan
Ansari
Earthquake Risk Management Research Center, International Institute of Earthquake Engineering and Seismology (IIEES), Tehran, Iran
author
text
article
2017
eng
One of the most critical steps of seismic hazard and risk analysis is selecting the appropriate GMPEs to address strong ground motion based on earthquakeparameters. In fact, appropriate modeling of this epistemic source of uncertainty in analysis is a non-trivial approach that is an active area of research. From statistical point of view, this issue can be resolved by measuring the good-of-fit, which describes how well a model fits a set of observations. In this study, the suitability of a set of local, regional and global GMPEs based on the three approaches of LH, LLH and EDR for two distinct seismotectonic regions of Iran have been assessed. Analyses show general compatibility between the order of ranking in both approaches of LH and LLH while the order of ranking in EDR approach shows significant differences. This contradiction come from their conceptual differences, in which the approaches like LH and LLH the overall performance of a model is assessed in an index and the individual effect of other parameters are not examined.
Journal of Seismology and Earthquake Engineering
International Institute of Earthquake Engineering and Seismology
1735-1669
19
v.
2
no.
2017
139
161
http://www.jsee.ir/article_240760_330621d09ccfa18823d7f6ee8466e686.pdf
Estimating the Loading Pattern Factor of Modal Pushover Analysis (MPA) for Integrated Bridges Using IDA Responses
Yaser
Nasiri
Islamic Azad University, Science and Research Branch, Tehran
author
Panam
Zarfam
Islamic Azad University, Science and Research Branch, Tehran
author
text
article
2017
eng
In this paper, a new applied relationship is introduced for the analysis of integrated bridges where no expansion joint embedded on the deck. It can be used to investigate the seismic behavior and actual performance of integrated bridges under earthquake force and, in spite of its simplicity, its accuracy is acceptable. In fact, this relationship can be considered as a combination of incremental dynamic analysis and modal pushover analysis, benefiting from the advantages of both approaches, i.e. an appropriate loading pattern factor of Modal Pushover Analysis can be obtained by using Incremental Dynamic approach. To this end, the average acceleration - displacement and average acceleration - shear base of 120 earthquake records applied on the bridge are calculated and then the obtained incremental dynamic curve is plotted in the coordinates of displacement and shear base. For the obtained modal pushover curve, the sum of the first three SRSS modes is selected. The literature shows no record of the study conducted on the comparison of the two curves. In this paper, the aforementioned comparison was made using Incremental Dynamic Approach through examining six regular and irregular integrated bridges and applying 120 earthquake records in 10 acceleration levels. It was observed that the accuracy of the proposed relationship in predicting the bridge displacements and shear forces of columns' piers was high, and the calculation output showed negligible differences with dynamic analyze results. In this study, the soil-structure interaction is ignored.
Journal of Seismology and Earthquake Engineering
International Institute of Earthquake Engineering and Seismology
1735-1669
19
v.
2
no.
2017
163
169
http://www.jsee.ir/article_240761_8d80a543bc02d4f3e9c6d599a7740c96.pdf
Evaluation of Design Parameters on PBD of RC Buildings with Masonry Infills
Bhushan
Raisinghani
C.U. SHAH COLLEGE OF ENGINEERING & TECHNOLOGY
author
text
article
2017
eng
Masonry infills are provided in almost all residential buildings as enclosure. The building analysis and designs are carried out considering a representativeempirical time period. The yield strength of URM infilled frames is much higher, and yield displacement is smaller for bare frames, providing higher ductility. The extent of damage to infill elements define the hazard level imposed and the corresponding risk associated with it. In this paper, the performance of RC building with infills is evaluated using pushover analysis for various seismic hazard levels and loading patterns as per ATC40 & FEMA356 in ETABS. A seven storey regular RC building is located in seismic zone-V (IS1893-0.36 g). The parameters of evaluation include time period formula, modelling technique of infill, masonry units used in practice, and location of openings in building. The code provisions for open ground storey buildings have been evaluated for performance assessment. Under 0.36 g hazard level, the building frame satisfied Life Safety performance objective under the three lateral loading patterns. It is found that AAC masonry blocks least affect the performance of frame elements and also the required failure mode for the structure.
Journal of Seismology and Earthquake Engineering
International Institute of Earthquake Engineering and Seismology
1735-1669
19
v.
2
no.
2017
123
138
http://www.jsee.ir/article_240759_678027232729c24d22e664dcff93655d.pdf