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seismic-hazards
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Seismic hazard analysis and obtaining uniform hazard spectra for rasht region, iran
, Article Proceedings of the Annual International Conference on Architecture and Civil Engineering, 27 May 2019 through 28 May 2019 ; 2019 , Pages 278-284 ; 2301394X (ISSN) ; Hadinejad, A ; Anderson M. S. T ; Anderson P. C. O ; Sharif University of Technology
Global Science and Technology Forum
2019
Abstract
— In this study probabilistic seismic hazard analysis is carried out for Rasht province, a city located in IRAN, and assessment of probable Peak Ground Acceleration (PGA) and uniform hazard spectra (UHS) for two levels of hazard are presented. Achieving this goal, seismic catalogues of all historical instrumentally recorded earthquakes since 4 th century BC up to 2018, in a radius of 200 km around Rasht city, has been gathered and processed for elimination of the aftershocks and foreshocks from main occurrences list and then the seismicity parameters have been obtained by Kijko [2000] method. In order to determine the PGA over bedrock, tree different attenuation relationships of Sadigh et...
Seismic hazard analysis and obtaining uniform hazard spectra for rasht region, iran
, Article Proceedings of the Annual International Conference on Architecture and Civil Engineering, 27 May 2019 through 28 May 2019 ; 2019 , Pages 278-284 ; 2301394X (ISSN) ; Hadinejad, A ; Sharif University of Technology
Global Science and Technology Forum
2019
Abstract
— In this study probabilistic seismic hazard analysis is carried out for Rasht province, a city located in IRAN, and assessment of probable Peak Ground Acceleration (PGA) and uniform hazard spectra (UHS) for two levels of hazard are presented. Achieving this goal, seismic catalogues of all historical instrumentally recorded earthquakes since 4 th century BC up to 2018, in a radius of 200 km around Rasht city, has been gathered and processed for elimination of the aftershocks and foreshocks from main occurrences list and then the seismicity parameters have been obtained by Kijko [2000] method. In order to determine the PGA over bedrock, tree different attenuation relationships of Sadigh et...
Addressing the epistemic uncertainty in seismic hazard analysis as a basis for seismic design by emphasizing the knowledge aspects and utilizing imprecise probabilities
, Article Bulletin of Earthquake Engineering ; Volume 20, Issue 2 , 2022 , Pages 741-764 ; 1570761X (ISSN) ; Rofooei, F. R ; Sharif University of Technology
Springer Science and Business Media B.V
2022
Abstract
Epistemic uncertainty in seismic hazard analysis is traditionally addressed by utilizing a logic-tree structure with subjective probabilities for branches. However, many studies have argued that probability is not a suitable choice for addressing epistemic uncertainties; in particular in addressing the background knowledge supporting the probabilities. In this regard, the application of imprecise probability (IP) is investigated. It is discussed that IP could provide a flexible tool for a more objective presentation of experts' knowledge. Moreover, the importance of addressing the strength of knowledge and surprises relative to knowledge in seismic hazard analysis along with methods to do...
Addressing the epistemic uncertainty in seismic hazard analysis as a basis for seismic design by emphasizing the knowledge aspects and utilizing imprecise probabilities
, Article Bulletin of Earthquake Engineering ; 2021 ; 1570761X (ISSN) ; Rahimzadeh Rofooei, F ; Sharif University of Technology
Springer Science and Business Media B.V
2021
Abstract
Epistemic uncertainty in seismic hazard analysis is traditionally addressed by utilizing a logic-tree structure with subjective probabilities for branches. However, many studies have argued that probability is not a suitable choice for addressing epistemic uncertainties; in particular in addressing the background knowledge supporting the probabilities. In this regard, the application of imprecise probability (IP) is investigated. It is discussed that IP could provide a flexible tool for a more objective presentation of experts' knowledge. Moreover, the importance of addressing the strength of knowledge and surprises relative to knowledge in seismic hazard analysis along with methods to do...
Probabilistic Estimation of Residual Drift Demands for Seismic Assessment of Multi-Story Framed Buildings Subjected to Near-Field Earthquakes
, M.Sc. Thesis Sharif University of Technology ; Rahimzadeh Rofooei, Fayaz (Supervisor)
Abstract
In performance-based earthquake engineering methodologies, it is necessary to estimate the probability of seismic structural demands exceeding a specified performance state under different seismic hazard levels. This methodology requires a probabilistic framework in which estimation of specific seismic demands and related uncertainties should be incorporated. Probabilistic Seismic Hazard Analysis (PSHA) allows the estimation of the mean annual frequency (MAF) of exceedance of a ground motion parameter or a linear elastic response spectral ordinate, taking into account the seismic hazard in a site with specified geological conditions. In performance-based seismic assessment of existing...
Structural reliability approach to analysis of probabilistic seismic hazard and its sensitivities
, Article Bulletin of Earthquake Engineering ; Volume 17, Issue 3 , 2019 , Pages 1331-1359 ; 1570761X (ISSN) ; Mahsuli, M ; Sharif University of Technology
Springer Netherlands
2019
Abstract
This paper presents a new probabilistic framework for seismic hazard assessment and hazard sensitivity analysis. Hazard in this context means the probability of exceeding a measure of ground shaking intensity, such as peak ground acceleration and spectral acceleration. The main components of the proposed framework include structural reliability methods to estimate exceedance probabilities and their sensitivities, and multiple probabilistic models for earthquake occurrence, magnitude, location, and ground motion. This paper presents two analysis approaches. The first approach utilizes the first- and second-order reliability methods and importance sampling. This approach efficiently yields the...
Probabilistic seismic hazard analysis of Iran using reliability methods
, Article Bulletin of Earthquake Engineering ; Volume 17, Issue 3 , 2019 , Pages 1117-1143 ; 1570761X (ISSN) ; Rahimi, H ; Bakhshi, A ; Sharif University of Technology
Springer Netherlands
2019
Abstract
Structural reliability methods are employed in this paper for nationwide probabilistic seismic hazard analysis of Iran and in-depth seismic hazard and hazard sensitivity analysis of Downtown Tehran. The companion paper proposes two analysis approaches based on reliability methods and presents the technical framework for such analyses. The first approach was based on Monte Carlo sampling reliability analysis, which is employed here to conduct hazard analysis at a grid comprising 3695 sites throughout Iran. The results are used to produce nationwide hazard maps for the peak ground acceleration, spectral acceleration, and cumulative absolute velocity. The other analysis approach employs the...
Incorporation of Forward Directivity in Near-Fault Ground Motions into Probabilistic Seismic Hazard Analysis
, M.Sc. Thesis Sharif University of Technology ; Golafshani, Ali Akbar (Supervisor)
Abstract
Ground motions in close proximity to the causative fault of an earthquake can be significantly affected by the propagation of rupture. In particular, when the rupture and slip direction relative to a site coincide and a significant portion of the fault ruptures towards the site, the ground motion can exhibit the effects of Forward-Directivity (FD). Pulse-like near-fault ground motions resulting from directivity effects are a special class of ground motions that are challenging to characterize for seismic performance assessment. These motions contain a pulse in the velocity time history of the motion, often occurring in the direction perpendicular to the fault rupture at locations near the...
A Framework to Select the Appropriate Combination of Retrofit and Insurance in Order to Reduce Earthquake Losses
, M.Sc. Thesis Sharif University of Technology ; Haj Kazem Kashani, Hamed (Supervisor)
Abstract
The aim of this research is presentation of A framework to select the appropriate combination of retrofit and insurance in order to reduce earthquake losses. The vulnerability of buildings to earthquakes can lead to significant damage to owners and residents of these buildings. It is imperative that appropriate measures be taken to reduce these adverse effects before the risk occurs. Some of these measures, such as seismic retrofit of buildings, can reduce the vulnerability of buildings and, consequently, financial and human losses. Some other measures like insurance, in the event of an earthquake, can reduce the financial losses incurred by owners and residents of vulnerable buildings....
The Effect of Exact and Approximate Distribution of Conditional Spectrum in Probabilistic Estimation of Structural Demands
, M.Sc. Thesis Sharif University of Technology ; Golafshani, Ali Akbar (Supervisor)
Abstract
In this thesis several methodological aspects of both conventional and novel approaches to probabilistic seismic hazard assessment are discussed here along with subjects more strictly pertinent to structural and geotechnical engineering. This work, however, has a unique, ultimate goal: to provide procedures for an effective and practical probabilistic estimation of structural demand of offshore platforms due to seismic ground shaking.In modern multi-level design and rehabilitation procedures, structural performance is in fact quantified by deformation demand levels exceeded with a specified annual frequency of structural life. We refer to this as Probabilistic Seismic Demand Analysis (PSDA)....
A Framework for Seismic Risk Assessment of Electrical Substation Equipment with Reliability and Endurance Time Methods
, M.Sc. Thesis Sharif University of Technology ; Esmaeil Purestekanchi, Homayoon (Supervisor)
Abstract
Influences of dynmic interaction between substation equipment on responses and fragility are studied. Proposing a framework for seismic risk analysis of substation equipment using reliability and endurance time methods is another aim of this project. Risk, in this contex, means the probability of exceeding monetary loss. Three dimensional models of four vulnerable types of equipment including surge arrester, current transformer, circuit breaker and disconnect switch are developed and verified. Six different systems of equipment connected through rigid bus bars comprising of two, three and four equipment are considered. Fragility curves are developed for equipment in both unconnected and...
The Effect of Earthquake Repeated Cycles in Performance Based Design Methodology Utilizing Energy Concept
, M.Sc. Thesis Sharif University of Technology ; Bakhshi, Ali (Supervisor)
Abstract
Due to structural and nonstructural damage after the occurrence of Northridge 1994 and Kobe 1995 earthquakes, Seismic design basics was modified and philosophy of performance based design was suggested. In this novel solution, Predefined limitations are considered. Performance criteria were usually related to displacement or other correlated factors such as hinge plastic rotation. All the mentioned limitations are related to different damage states.Most of the codes and articles use following assumptions for assessing structural performance: 1) considering first vibrational mode for structural response to any seismic excitation regardless of seismic input acceleration records or structural...
Modeling of Epistemic Uncertainties in Seismic Hazard Analysis Based on Reliability Methods
, M.Sc. Thesis Sharif University of Technology ; Mahsouli, Mojtaba (Supervisor)
Abstract
The primary objective of this thesis is comprehensive treatment of epistemic uncertainties in probabilistic seismic hazard analysis based on structural reliability methods. The classical methods of probabilistic seismic hazard analysis, i.e., PSHA, traditionally consider a limited number of uncertainties. The ones that they do consider comprise the aleatory uncertainty in the magnitude, the distance, and the residuals of ground motion prediction equations and the epistemic uncertainty in the intensity measures predicted by different such equations. However, there are many sources of epistemic uncertainty that, according to past studies, have a significant impact on the upper tail of the...
Seismic hazard assessment for two cities in Eastern Iran
, Article Earthquake and Structures ; Volume 8, Issue 3 , 2015 , Pages 681-697 ; 20927614 (ISSN) ; Kamali Asl, A ; Sharif University of Technology
Techno Press
2015
Abstract
Iran as one of the countries located on the Alpine-Himalayan seismic belt has recently experienced a few number of catastrophic earthquakes. A well-known index of how buildings are affected by earthquakes is through assessment of probable Peak Ground Acceleration (PGA) and structures' response spectra. In this research, active faults around Kerman and Birjand, two major cities in eastern parts of Iran, have been considered. Seismic catalogues are gathered to categorize effects of surrounding faults on seismicity of the region. These catalogues were further refined with respect to time and space based on Knopoff-Gardner algorithm in order to increase statistical independency of events....
Probabilistic seismic hazard analysis of Iran using reliability methods
, Article Bulletin of Earthquake Engineering ; 2018 ; 1570761X (ISSN) ; Rahimi, H ; Bakhshi, A ; Sharif University of Technology
Springer Netherlands
2018
Abstract
Structural reliability methods are employed in this paper for nationwide probabilistic seismic hazard analysis of Iran and in-depth seismic hazard and hazard sensitivity analysis of Downtown Tehran. The companion paper proposes two analysis approaches based on reliability methods and presents the technical framework for such analyses. The first approach was based on Monte Carlo sampling reliability analysis, which is employed here to conduct hazard analysis at a grid comprising 3695 sites throughout Iran. The results are used to produce nationwide hazard maps for the peak ground acceleration, spectral acceleration, and cumulative absolute velocity. The other analysis approach employs the...
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) ; Azarbakht, A ; Tabandeh, A ; Akbar Golafshani, A ; Sharif University of Technology
Elsevier
2012
Abstract
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...
Seismic Hazard Assessment in the Lifetime Duration of Steel MRF Structures Considering Aftershocks
, M.Sc. Thesis Sharif University of Technology ; Esmaeil Pourstekanchi, Homayoon (Supervisor)
Abstract
Following a large earthquake, numerous aftershocks can be triggered due to the complex stress interaction between and within tectonic plates. The aftershocks have the potential to cause severe weakening of mainshock-damaged buildings, threaten life safety, hamper reoccupation and restoration of buildings, and increase financial loss. The probability of aftershocks has not been included in the description of seismic hazard in performance-based earthquake engineering. This study proposes methodologies and a framework to investigate the seismic performance in the lifetime of steel MRF structures subjected to mainshock-aftershock sequences. The case studies correspond to three SAC 2D steel MRF...
Seismic Risk Analysis of the City of Golpayegan Using Reliability Methods
, M.Sc. Thesis Sharif University of Technology ; Mahsuli, Mojtaba (Supervisor)
Abstract
This thesis presents the seismic hazard and seismic risk analysis of the City of Golpayegan using reliability methods and multiple interacting probabilistic models. These models evaluate the seismic hazard intensity by simulating the hazard event and evaluate the seismic risk by simulating the building portfolio and infrastructure systems under the hazard event and quantifying the ensuing consequences. In this context, hazard is the exceedance probability of a ground shaking intensity measure, and risk is the exceedance probability of social and economic losses. This is the first time in the literature that reliability methods are applied in evaluating the seismic risk of a real-world city...
Risk-Based Seismic Design of Buildings in the Context of Cities,with Rigorous Uncertainty Modeling, and Proposing Efficient Computational Methods
, Ph.D. Dissertation Sharif University of Technology ; Rahimzadeh Rofooei, Fayaz (Supervisor)
Abstract
The main goal of the current building design codes is to protect life safety, and generally, they do not directly address other societal, economic, etc., concerns regarding earthquakes. However, recent earthquakes around the world have shown that the effects of earthquakes' damages and losses can go beyond life-safety concerns. This observation has led many renowned scholars, organizations, and agencies to state the need to change the current design codes. In this regard, this thesis investigates the basis of setting the seismic design requirements and suggests a method in this respect. The study consists of two main parts. Part I (theory and design methodology) discusses some theoretical...
Seismic Risk Assessment of Tehran Masonry School Buildings
, M.Sc. Thesis Sharif University of Technology ; Bakhshi, Ali (Supervisor)
Abstract
This thesis aims to assess the seismic risk of the community of schools with masonry buildings in the Tehran metropolitan in the next 50 years and to prioritize the buildings of this community for seismic retrofit based on the optimal mitigation of risk of the community. Tehran is among the largest cities with the highest level of seismic risk in the world, and Masonry buildings are among the structures with poor seismic performance; Therefore, it is essential to conduct a comprehensive and accurate evaluation of the seismic risk of schools, as one of the most critical and sensitive occupancies, in this region and with this type of structure. It is also very beneficial to reduce the seismic...