scholarly journals Development of Empirical Fragility Curves in Earthquake Engineering considering Nonspecific Damage Information

2018 ◽  
Vol 2018 ◽  
pp. 1-13 ◽  
Author(s):  
Jung J. Kim
Keyword(s):  
Earthquake Engineering ◽  
Fragility Curves ◽  
Evidence Theory ◽  
Possibility Theory ◽  
Seismic Damage ◽  
Damage State ◽  
Lognormal Distributions ◽  
Damage States ◽  
Damage Data ◽  
Conservative Estimation

As a function of fragility curves in earthquake engineering, the assessment of the probability of exceeding a specific damage state according to the magnitude of earthquake can be considered. Considering that the damage states for fragility curves are generally nested to each other, the possibility theory, a special form of the evidence theory for nested intervals, is applied to generate fragility information from seismic damage data. While the lognormal distributions are conventionally used to generate fragility curves due to their simplicity and applicability, the methodology to use the possibility theory does not require the assumption of distributions. Seismic damage data classified by four damage levels were used for a case study. The resulted possibility-based fragility information expressed by two monotone measures, “possibility” and “certainty,” are compared with the conventional fragility curves based on probability. The results showed that the conventional fragility curves provide a conservative estimation at the relatively high earthquake magnitude compared with the possibility-based fragility information.

A Beta Distribution Model for Characterizing Earthquake Damage State Distribution

2015 ◽  
Vol 31 (3) ◽  
pp. 1337-1352 ◽  
Author(s):  
David Lallemant ◽  
Anne Kiremidjian
Keyword(s):  
Beta Distribution ◽  
Fragility Curves ◽  
Earthquake Damage ◽  
Distribution Model ◽  
State Distribution ◽  
Damage State ◽  
Damage Probability Matrices ◽  
Damage States ◽  
Damage Data ◽  
Probability Matrices

This study investigates methods for modeling the distribution of post-earthquake damage among categorical damage states. Specifically, it is demonstrated that the beta distribution is a good model for characterizing the complete probability distribution of damage states conditioned on ground-motion intensity. Based on extensive post-earthquake damage surveys following the 2010 earthquake in Haiti, the paper proposes the method-of-moments and maximum likelihood estimate-based formulations to fit a beta distribution model to grouped categorical damage data. The beta distribution model is further compared with one based on the binomial distribution, often used to estimate damage state distribution. The study demonstrates that the beta distribution results in little bias and variance in predictions of damage and loss. This model can be the basis for developing damage probability matrices, fragility curves, post-disaster damage estimations, risk assessments, and more.

Seismic risk assessment of RC curved bridges through fragility curves

2019 ◽  
Author(s):  
Nina N. Serdar ◽  
Jelena R. Pejovic ◽  
Radenko Pejovic ◽  
Miloš Knežević
Keyword(s):  
Risk Assessment ◽  
Urban Areas ◽  
Seismic Risk ◽  
Seismic Vulnerability ◽  
Fragility Curves ◽  
Curved Bridges ◽  
Damage State ◽  
Seismic Risk Assessment ◽  
Probability Of Exceedance ◽  
Damage States

<p>It is of great importance that traffic network is still functioning in post- earthquake period, so that interventions in emergency situations are not delayed. Bridges are part of the traffic system that can be considered as critical for adequate post-earthquake response. Their seismic response often dominate the response and reliability of overall transportation system, so special attention should be given to risk assessment for these structures. In seismic vulnerability and risk assessment bridges are often classified as regular or irregular structures, dependant on their configuration. Curved bridges are considered as irregular and unexpected behaviour during seismic excitation is noticed in past earthquake events. Still there are an increasing number of these structures especially in densely populated urban areas since curved configuration is often suitable to accommodate complicated location conditions. In this paper special attention is given to seismic risk assessment of curved reinforce concrete bridges through fragility curves. Procedure for developing fragility curves is described as well as influence of radius curvature on their seismic vulnerability is investigated. Since vulnerability curves provide probability of exceedance of certain damage state, four damage states are considered: near collapse, significant damage, intermediate damage state, onset of damage and damage limitation. As much as possible these damage states are related to current European provisions. Radius of horizontal curvature is varied by changing subtended angle: 25 °, 45 ° and 90 °. Also one corresponding straight bridge is analysed. Nonlinear static procedure is used for developing of fragility curves. It was shown that probability of exceedance of certain damage states is increased as subtended angle is increased. Also it is determined that fragility of curved bridges can be related to fragility of straight counterparts what facilitates seismic evaluation of seismic vulnerability of curved bridges structures.</p>

scholarly journals Relationships between empirical damage and direct/indirect costs for the assessment of seismic loss scenarios

2021 ◽  
Author(s):  
Marco Di Ludovico ◽  
Giuseppina De Martino ◽  
Andrea Prota ◽  
Gaetano Manfredi ◽  
Mauro Dolce
Keyword(s):  
Empirical Data ◽  
Residential Buildings ◽  
Fragility Curves ◽  
Unit Cost ◽  
Indirect Costs ◽  
Mitigation Strategies ◽  
Damage State ◽  
Reconstruction Process ◽  
2009 L’Aquila Earthquake ◽  
Damage States

AbstractThe definition of relationships between damage and losses is a crucial aspect for the prediction of seismic effects and the development of reliable models to define risk maps, loss scenarios and mitigation strategies. The paper focuses on the analysis of post-earthquake empirical data to define relationships between buildings’ damage expressed as usability rating or as global damage state and the associated costs for repair (i.e. direct costs) or for population assistance (i.e. a part of total indirect costs). The analysis refers to the data collected on residential buildings damaged by 2009 L'Aquila earthquake. For different usability rating or damage states, the paper presents the costs expressed in terms of percentage with respect to the reference unit cost of a new building (%Cr and %Ca for repair and population assistance costs, respectively). In particular, the costs analysis refers to undamaged, lightly or severely damaged buildings classified according to usability rating (i.e. A, B-C or E according to Italian classification) or to five different global Damage States (DSs). DSs comply with European Macroseismic Scale (EMS-98) and derive from literature available matrices properly defined to convert empirical damage to structural and non-structural components into building global damage. The %Cr probability density functions and relevant statistics derive from the analysis of actual data of post-earthquake reconstruction process, while, to determine those related to %Ca, a deep analysis of population assistance types, person/month assistance cost for each assistance form, and a methodology to associate such costs to each building are herein presented and discussed. Finally, the paper presents a relationship calibrated on empirical data to directly correlate repair costs on a building with assistance costs to their occupants. The relationships between empirical damage and direct and indirect costs herein presented are of paramount importance because they allow reliable loss scenarios to be defined by simply using literature fragility curves (defined according to empirical or mechanical approaches) aimed at evaluating the probability of exceeding different usability rating or damage states of existing buildings.

Seismic Fragility Curves for On-Grade Steel Tanks

2000 ◽  
Vol 16 (4) ◽  
pp. 801-815 ◽  
Author(s):  
Michael J. O'Rourke ◽  
Pak So
Keyword(s):  
Fragility Curves ◽  
Damage State ◽  
Ground Acceleration ◽  
Technical Literature ◽  
Ground Shaking ◽  
Liquid Storage ◽  
Damage States ◽  
Earthquake Loss ◽  
Steel Tanks ◽  
Grade Steel

The study reported herein attempts to characterize the seismic behavior of cylindrical on-grade, steel liquid storage tanks subject to the ground shaking hazard. The behavior is quantified by fragility curves that resulted from an analysis of the reported performance of over 400 tanks in nine separate earthquake events. The damage states used herein to characterize damage (i.e., slight, moderate, etc.) are intended to mirror damage state descriptions in the HAZUS Earthquake Loss Estimation Methodology. The amount of ground shaking is quantified by the peak ground acceleration (PGA) at the site. The influence of the tank's height to diameter ratio, H/D, as well as the relative amount of stored contents, % Full, are investigated and were found to have had a significant effect upon tank seismic performance. Finally, the fragility curves developed herein are compared to corresponding relations currently available in the technical literature.

scholarly journals Seismic Vulnerability Assessment of a Reinforced Concrete Building Located in India

2019 ◽  
Vol 8 (11S) ◽  
pp. 310-314
Keyword(s):  
Vulnerability Assessment ◽  
Seismic Vulnerability ◽  
Fragility Curves ◽  
Equivalent Linearization ◽  
Spectral Acceleration ◽  
Damage State ◽  
Ground Acceleration ◽  
Seismic Vulnerability Assessment ◽  
Performance Point ◽  
Damage States

Over the recent years the natural disaster especially due to the earthquake effect on buildings increases which causes loss of life and property in many places all over the world. The latest development leads to finding the direct losses and damage states of the buildings for various intensities of earthquake ground motions. In the present study, seismic vulnerability assessment was done for a medium rise building (G+5). The design peak ground acceleration of 0.16g and 0.36g were considered for the risk assessment. The nonlinear static pushover analysis was done to fine the performance point, spectral acceleration and corresponding spectral acceleration by Equivalent Linearization (EL) method given by Federal Emergency Management Agency (FEMA-440). The four damage states such as slight, moderate, extreme and collapse has been considered as per HAZUS-MR4. The seismic vulnerability in terms of fragility curves was developed to evaluate the damage probabilities based on HAZUS methodology. The discrete and cumulative damage probability was found for all the damage states of the building which shows the building at 0.16g experience slight damage whereas at 0.36g the moderate damage state equally becomes predominant.

scholarly journals Nonlinear Dynamic Analysis of Masonry Buildings and Definition of Seismic Damage States

2016 ◽  
Vol 10 (1) ◽  
pp. 192-209 ◽  
Author(s):  
A.J. Kappos ◽  
V.K. Papanikolaou
Keyword(s):  
Fragility Curves ◽  
Pushover Analysis ◽  
Nonlinear Dynamic Analysis ◽  
Critical Issue ◽  
Seismic Damage ◽  
Masonry Building ◽  
Nonlinear Behaviour ◽  
Building Stock ◽  
Damage States ◽  
Diaphragm Action

A large part of the building stock in seismic-prone areas worldwide are masonry structures that have been designed without seismic design considerations. Proper seismic assessment of such structures is quite a challenge, particularly so if their response well into the inelastic range, up to local or global failure, has to be predicted, as typically required in fragility analysis. A critical issue in this respect is the absence of rigid diaphragm action (due to the presence of relatively flexible floors), which renders particularly cumbersome the application of popular and convenient nonlinear analysis methods like the static pushover analysis. These issues are addressed in this paper that focusses on a masonry building representative of Southern European practice, which is analysed in both its pristine condition and after applying retrofitting schemes typical of those implemented in pre-earthquake strengthening programmes. Nonlinear behaviour is evaluated using dynamic response-history analysis, which is found to be more effective and even easier to apply in this type of building wherein critical modes are of a local nature, due to the absence of diaphragm action. Fragility curves are then derived for both the initial and the strengthened building, exploring alternative definitions of seismic damage states, including some proposals originating from recent international research programmes.

scholarly journals Seismic Fragility Assessment of Steel Liquid Storage Tanks

2015 ◽  
Author(s):  
Konstantinos Bakalis ◽  
Dimitrios Vamvatsikos ◽  
Michalis Fragiadakis
Keyword(s):  
Failure Modes ◽  
Fragility Curves ◽  
Seismic Fragility ◽  
Assessment Procedure ◽  
Storage Tanks ◽  
Component Level ◽  
Damage State ◽  
Liquid Storage ◽  
Damage States ◽  
Buckling Failure

A seismic fragility assessment procedure is developed for atmospheric steel liquid storage tanks. Appropriate system and component-level damage states are defined by identifying the failure modes that may occur during a strong ground motion. Special attention is paid to the elephant’s foot buckling failure mode, where the estimation of the associated capacity and demand requires thorough consideration within a probabilistic framework. A novel damage state is introduced to existing procedures with respect to the uncontrollable loss of containment scenario. Fragility curves are estimated by introducing both aleatory and epistemic sources of uncertainty, thus providing a comprehensive methodology for the seismic risk assessment of liquid storage tanks. The importance of dynamic buckling is acknowledged and the issue of non-sequential damage states is finally revealed.

scholarly journals Relationships Between Empirical Damage and Direct/Indirect Costs for the Assessment of Seismic Loss Scenarios

2021 ◽  
Author(s):  
Marco Di Ludovico ◽  
Giuseppina De MArtino ◽  
Andrea Prota ◽  
Gaetano Manfredi ◽  
Mauro Dolce
Keyword(s):  
Empirical Data ◽  
Residential Buildings ◽  
Fragility Curves ◽  
Unit Cost ◽  
Indirect Costs ◽  
Mitigation Strategies ◽  
Damage State ◽  
Reconstruction Process ◽  
2009 L’Aquila Earthquake ◽  
Damage States

Abstract The definition of relationships between damage and losses is a crucial aspect for the prediction of seismic effects and the development of reliable models to define risk maps, loss scenarios and mitigation strategies. The paper focuses on the analysis of post-earthquake empirical data to define relationships between buildings’ damage expressed as usability rating or as global damage state and the associated costs for repair (i.e. direct costs) or for population assistance (i.e. a part of total indirect costs). The analysis refers to the data collected on residential buildings damaged by 2009 L'Aquila earthquake. For different usability rating or damage states, the paper presents the costs expressed in terms of percentage with respect to the reference unit cost of a new building (%Cr and %Ca for repair and population assistance costs, respectively). In particular, the costs analysis refers to undamaged, lightly or severely damaged buildings classified according to usability rating (i.e. A, B-C or E according to Italian classification) or to five different global Damage States (DSs). DSs comply with European Macroseismic Scale (EMS-98) and derive from literature available matrices properly defined to convert empirical damage to structural and non-structural components into building global damage. The %Cr probability density functions and relevant statistics derive from the analysis of actual data of post-earthquake reconstruction process, while, to determine those related to %Ca, a deep analysis of population assistance types, person/month assistance cost for each assistance form, and a methodology to associate such costs to each building are herein presented and discussed. Finally the paper presents a relationship calibrated on empirical data to directly correlate repair costs on a building with assistance costs to their occupants.The relationships between empirical damage and direct and indirect costs herein presented are of paramount importance because they allow reliable loss scenarios to be defined by simply using literature fragility curves (defined according to empirical or mechanical approaches) aimed at evaluating the probability of exceeding different usability rating or damage states of existing buildings.

Probabilistic Performance Assessment of Retrofitted Horizontally Curved Multi-Frame RC Box-Girder Bridges

2017 ◽  
Vol 11 (04) ◽  
pp. 1750010 ◽  
Author(s):  
Hossein Pahlavan ◽  
Behzad Zakeri ◽  
Gholamreza Ghodrati Amiri
Keyword(s):  
Bridge Deck ◽  
Fragility Curves ◽  
Time History ◽  
Damage State ◽  
Box Girder Bridges ◽  
Box Girder ◽  
Horizontally Curved ◽  
Girder Bridges ◽  
Damage States ◽  
Nonlinear Time History

Bridge horizontal deck curvature and the prevalence of in-span hinges in multi-frame RC box-girder bridges have reinforced this class of bridge to response with unique dynamic behavior during seismic excitations. This paper assesses the impacts of 10 different retrofit strategies on the vulnerability of curved multi-frame RC box-girder bridges with multi-column bents based on nonlinear time history analyses in OpenSEES. Consistent with HAZUS-MH definitions, fragility curves corresponding to four damage states at the component and system levels are developed for various bridge deck radii. The results indicate that combinations of retrofit strategies should be used to enhance the desirable level of bridge performance. Moreover, the most effective retrofit strategy in reducing probable damage for a given intensity is dependent on the bridge deck radius and is a function of the damage state of interest.

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