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1.
Infrastructure owners and operators, or governmental agencies, need rapid screening tools to prioritize detailed risk assessment and retrofit resources allocation. This paper provides one such tool, for use by highway administrations, based on Bayesian belief network (BBN) and aimed at replacing so‐called generic or typological seismic fragility functions for reinforced concrete girder bridges. Resources for detailed assessments should be allocated to bridges with highest consequence of damage, for which site hazard, bridge fragility, and traffic data are needed. The proposed BBN based model is used to quantify seismic fragility of bridges based on data that can be obtained by visual inspection and engineering drawings. Results show that the predicted fragilities are of sufficient accuracy for establishing relative ranking and prioritizing. While the actual data and seismic hazard employed to train the network (establishing conditional probability tables) refer to the Italian bridge stock, the network structure and engineering judgment can easily be adopted for bridges in different geographical locations. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
2.
Vulnerability assessment for historic buildings is usually carried out using capacity based approaches and prediction of losses
is obtained by using normal or lognormal distributions for expected levels of macro seismic intensity or peak ground accelerations.
Several authors have outlined the limitations of such approach. The paper presents a method to correlate analysis of seismic
vulnerability using a failure mechanisms approach to observed in situ damage. The various aspects of the procedure are highlighted with application to a real case. It is shown how once the typologies
within a sample have been identified, fragility curves for each of them can be derived and predictive cumulative damage curve
obtained for samples for which direct survey of damage data is lacking. Finally the paper shows how the failure mechanism
approach can be used to derive damage scenarios both in terms of spectral acceleration and spectral displacement 相似文献
3.
Seismic safety of low ductility structures used in Spain 总被引：1，自引：0，他引：1
The most important aspects of the design, seismic damage evaluation and safety assessment of structures with low ductility
like waffle slabs buildings or flat beams framed buildings are examined in this work. These reinforced concrete structural
typologies are the most used in Spain for new buildings but many seismic codes do not recommend them in seismic areas. Their
expected seismic performance and safety are evaluated herein by means of incremental non linear structural analysis (pushover
analysis) and incremental dynamic analysis which provides capacity curves allowing evaluating their seismic behavior. The
seismic hazard is described by means of the reduced 5% damped elastic response spectrum of the Spanish seismic design code.
The most important results of the study are the fragility curves calculated for the mentioned building types, which allow
obtaining the probability of different damage states of the structures as well as damage probability matrices. The results,
which show high vulnerability of the studied low ductility building classes, are compared with those corresponding to ductile
framed structures. 相似文献
4.
Many historic buildings in old urban centers in Eastern Canada are made of stone masonry reputed to be highly vulnerable to seismic loads.Seismic risk assessment of stone masonry buildings is therefore the first step in the risk mitigation process to provide adequate planning for retrofit and preservation of historical urban centers.This paper focuses on development of analytical displacement-based fragility curves reflecting the characteristics of existing stone masonry buildings in Eastern Canada.The old historic center of Quebec City has been selected as a typical study area.The standard fragility analysis combines the inelastic spectral displacement,a structure-dependent earthquake intensity measure,and the building damage state correlated to the induced building displacement.The proposed procedure consists of a three-step development process:(1) mechanics-based capacity model,(2) displacement-based damage model and(3) seismic demand model.The damage estimation for a uniform hazard scenario of 2% in 50 years probability of exceedance indicates that slight to moderate damage is the most probable damage experienced by these stone masonry buildings.Comparison is also made with fragility curves implicit in the seismic risk assessment tools Hazus and ELER.Hazus shows the highest probability of the occurrence of no to slight damage,whereas the highest probability of extensive and complete damage is predicted with ELER.This comparison shows the importance of the development of fragility curves specific to the generic construction characteristics in the study area and emphasizes the need for critical use of regional risk assessment tools and generated results. 相似文献
5.
Clotaire Michel Helen Crowley Pia Hannewald Pierino Lestuzzi Donat Fäh 《Bulletin of Earthquake Engineering》2018,16(10):4639-4660
The development of fragility curves to perform seismic scenario-based risk assessment requires a fully probabilistic procedure in order to account for uncertainties at each step of the computation. This is especially true when developing fragility curves conditional on an Intensity Measure that is directly available from a ground-motion prediction equation. In this study, we propose a new derivation method that uses realistic spectra instead of design spectral shapes or uniform hazard spectra and allows one to easily account for the features of the site-specific hazard that influences the fragility, without using non-linear dynamic analysis. The proposed method has been applied to typical school building types in the city of Basel (Switzerland) and the results have been compared to the standard practice in Europe. The results confirm that fragility curves are scenario dependent and are particularly sensitive to the magnitude of the earthquake scenario. The same background theory used for the derivation of the fragility curves has allowed an innovative method to be proposed for the conversion of fragility curves to a common IM (i.e. spectral acceleration or PGA). This conversion is the only way direct comparisons of fragility curves can be made and is useful when inter-period correlation cannot be used in scenario loss assessment. Moreover, such conversion is necessary to compare and verify newly developed curves against those from previous studies. Conversion to macroseismic intensity is also relevant for the comparison between mechanical-based and empirical fragility curves, in order to detect possible biases. 相似文献
6.
A. Martinelli G. Cifani G. Cialone L. Corazza A. Petracca G. Petrucci 《Soil Dynamics and Earthquake Engineering》2008,28(10-11):875
A procedure for assessing the seismic vulnerability of residential buildings is presented along with the results of its application in an Italian town in Abruzzo (Celano Aq). This procedure is part of a methodological proposal which includes specific studies on expected seismic inputs and site effects analyses. The procedure is based on a simplified collection of data, such as typological features and factors concerning the seismic behaviour of buildings, and provides an estimate of seismic vulnerability and an expected damage forecast using fragility curves. The instruments and methods used for the Celano project are an updated and improved version of those applied to previous vulnerability investigations. This paper demonstrates how this procedure can meet the objectives of the integrated methodology proposed. In fact, the information that can be obtained using this procedure—state of vulnerability, risk analyses and GIS presentations of damage scenarios—could be used in urban planning to reduce seismical risk. 相似文献
7.
Andreas J. Kappos Georgios Panagopoulos Christos Panagiotopoulos Gregorios Penelis 《Bulletin of Earthquake Engineering》2006,4(4):391-413
The methodology followed by the Aristotle University (AUTh) team for the vulnerability assessment of reinforced concrete (R/C) and unreinforced masonry (URM) structures is presented. The paper focuses on the derivation of vulnerability (fragility) curves in terms of peak ground acceleration (PGA), as well as spectral displacement (s
d), and also includes the estimation of capacity curves, for several R/C and URM building types. The vulnerability assessment methodology is based on the hybrid approach developed at AUTh, which combines statistical data with appropriately processed (utilising repair cost models) results from nonlinear dynamic or static analyses, that permit extrapolation of statistical data to PGA’s and/or spectral displacements for which no data are available. The statistical data used herein are from earthquake-damaged greek buildings. An extensive numerical study is carried out, wherein a large number of building types (representing most of the common typologies in S. Europe) are modelled and analysed. Vulnerability curves for several damage states are then derived using the aforementioned hybrid approach. These curves are subsequently used in combination with the mean spectrum of the Microzonation study of Thessaloniki as the basis for the derivation of new vulnerability curves involving spectral quantities. Pushover curves are derived for all building types, then reduced to standard capacity curves, and can easily be used together with the S
d fragility curves as an alternative for developing seismic risk scenarios. 相似文献
8.
9.
Vector-valued fragility functions for seismic risk evaluation 总被引：4，自引：4，他引：0
This article presents a method for the development of vector-valued fragility functions, which are a function of more than one intensity measure (IM, also known as ground-motion parameters) for use within seismic risk evaluation of buildings. As an example, a simple unreinforced masonry structure is modelled using state-of-the-art software and hundreds of nonlinear time-history analyses are conducted to compute the response of this structure to earthquake loading. Dozens of different IMs (e.g. peak ground acceleration and velocity, response spectral accelerations at various periods, Arias intensity and various duration and number of cycle measures) are considered to characterize the earthquake shaking. It is demonstrated through various statistical techniques (including Receiver Operating Characteristic analysis) that the use of more than one IM leads to a better prediction of the damage state of the building than just a single IM, which is the current practice. In addition, it is shown that the assumption of the lognormal distribution for the derivation of fragility functions leads to more robust functions than logistic, log-logistic or kernel regression. Finally, actual fragility surfaces using two pairs of IMs (one pair are uncorrelated while the other are correlated) are derived and compared to scalar-based fragility curves using only a single IM and a significant reduction in the uncertainty of the predicted damage level is observed. This type of fragility surface would be a key component of future risk evaluations that take account of recent developments in seismic hazard assessment, such as vector-valued probabilistic seismic hazard assessments. 相似文献
10.
The 1995 Kobe earthquake caused unprecedented damage to buildings and civil infrastructures in the city of Kobe and its surrounding areas. In order to evaluate the structural damage in this area due to the earthquake, it is important to estimate the distribution of earthquake ground motion. However, since the number of strong ground motion records is not enough in the heavily damaged areas, it is necessary to estimate the distribution using other data sources. In this paper, the fragility curves for low‐rise residential buildings were constructed using the recorded motions and the building damage data from the intensive field survey by the AIJ and CPIJ group. The fragility curves obtained were then employed to estimate the strong motion distribution in the district level for Kobe and the surrounding areas during the earthquake. The results may be useful to investigate the various damages caused by the earthquake. Copyright © 2001 John Wiley & Sons, Ltd. 相似文献
11.
Post-earthquake damage data represent an invaluable source of information for the seismic vulnerability assessment of the exposed building stock, as they are a direct evidence of the actual buildings’ performance under real seismic events. This paper exploits a robust and homogeneous database of damage data collected after the 2009 L’Aquila (Italy) earthquake, to derive damage probability matrices for several building typologies representative of the Italian building stock. To this aim, the first part of the work investigates several issues related to the definition of damage to be associated with each inspected building. Different approaches and damage conversion rules are applied, pointing out advantages and weaknesses of each one. Considering the widespread seismic damage observed on masonry infill panels and partitions of reinforced concrete constructions, the impact of this type of non-structural damage on empirical damage and functional loss distributions is explored. The second part of the study proposes different possible interpretations of the repartition of the observed damage in the different damage levels, showing in some cases a bimodal trend. Two novel hybrid procedures are outlined and compared with the classical binomial approach for predicting the subdivision of damage in the different levels. The application of the proposed methodologies to the different building typologies allows the selection, for each one, of the method providing the best fit to empirical results. The parameters required for the application of the optimal approach are reported in the paper, so that results can be used for forecasting the expected seismic damage in sites with similar seismic hazard and exposed buildings. 相似文献
12.
Empirical tsunami fragility curves are developed based on a Bayesian framework by accounting for uncertainty of input tsunami hazard data in a systematic and comprehensive manner. Three fragility modeling approaches, i.e. lognormal method, binomial logistic method, and multinomial logistic method, are considered, and are applied to extensive tsunami damage data for the 2011 Tohoku earthquake. A unique aspect of this study is that uncertainty of tsunami inundation data (i.e. input hazard data in fragility modeling) is quantified by comparing two tsunami inundation/run-up datasets (one by the Ministry of Land, Infrastructure, and Transportation of the Japanese Government and the other by the Tohoku Tsunami Joint Survey group) and is then propagated through Bayesian statistical methods to assess the effects on the tsunami fragility models. The systematic implementation of the data and methods facilitates the quantitative comparison of tsunami fragility models under different assumptions. Such comparison shows that the binomial logistic method with un-binned data is preferred among the considered models; nevertheless, further investigations related to multinomial logistic regression with un-binned data are required. Finally, the developed tsunami fragility functions are integrated with building damage-loss models to investigate the influences of different tsunami fragility curves on tsunami loss estimation. Numerical results indicate that the uncertainty of input tsunami data is not negligible (coefficient of variation of 0.25) and that neglecting the input data uncertainty leads to overestimation of the model uncertainty. 相似文献
13.
Carlo Del Gaudio Paolo Ricci Gerardo Mario Verderame 《Bulletin of Earthquake Engineering》2018,16(10):4581-4605
The simplified mechanical method POST (PushOver on Shear Type models) for seismic vulnerability assessment of RC buildings is used in this study to derive damage scenarios for a database of 7597 RC buildings subjected to the 2009 L’Aquila earthquake. POST allows the evaluation of fragility curves through the determination of the non-linear static response of RC buildings in closed form, assuming the hypothesis of shear type behaviour, and considering the influence of infill panels both in the derivation of structural response and in assessment of building damage, which is defined according to the European Macroseismic Scale EMS-98. The aim of the present study is to provide a much more significant and reliable validation of the methodology, thanks to a much wider database compared to previous studies, and based on a different application of the methodology, i.e. at building class-level instead of single building-level. To this aim, the main geometrical-typological characteristics of the analysed buildings (number of storeys, age of construction, building area) have been statistically characterized based on data collected from post-earthquake AeDES survey forms, considering both the variability of each single parameter and the correlation that exists between one parameter and the other. This also allows to analyse the effectiveness of the adopted analytical procedure in predicting the general trends of observed damage with these parameters, showing a good agreement between observed and predicted trends. The overall predicted damage scenarios are compared with the corresponding observed ones, collected from AeDES survey forms, highlighting, again, a good agreement. Finally, the assumed mechanical interpretation of damage classification of EMS-98 is validated through the comparison between the distributions of damage to vertical structures and infill panels and the corresponding observed post-earthquake damage data. 相似文献
14.
Seismic damage evaluation in urban areas using the capacity spectrum method: Application to Barcelona 总被引：8，自引：0，他引：8
Alex H. Barbat Luis G. Pujades Nieves Lantada 《Soil Dynamics and Earthquake Engineering》2008,28(10-11):851
Conceptual aspects related to seismic vulnerability, damage and risk evaluation are discussed first, together with a short review of the most widely used possibilities for seismic evaluation of structures. The capacity spectrum method and the way of obtaining seismic damage scenarios for urban areas starting from capacity and fragility curves are then discussed. The determination of capacity curves for buildings using non-linear structural analysis tools is then explained, together with a simplified expeditious procedure allowing the development of fragility curves. The seismic risk of the buildings of Barcelona, Spain, is analyzed in the paper, based on the application of the capacity spectrum method. The seismic hazard in the area of the city is described by means of the reduced 5% damped elastic response spectrum. The information on the buildings was obtained by collecting, arranging, improving and completing a broad database of the dwellings and current buildings. The buildings existing in Barcelona are mainly of two types: unreinforced masonry structures and reinforced concrete buildings with waffled-slab floors. The ArcView software was used to create a GIS tool for managing the collected information in order to develop seismic risk scenarios. This study shows that the vulnerability of the buildings is significant in Barcelona and, therefore, in spite of the low-to-moderate seismic hazard in the region, the expected seismic risk is considerable. 相似文献
15.
Empirical fragility curves, constructed from databases of thousands of building-damage observations, are commonly used for earthquake risk assessments, particularly in Europe and Japan, where building stocks are often difficult to model analytically (e.g. old masonry structures or timber dwellings). Curves from different studies, however, display considerable differences, which lead to high uncertainty in the assessed seismic risk. One potential reason for this dispersion is the almost universal neglect of the spatial variability in ground motions and the epistemic uncertainty in ground-motion prediction. In this paper, databases of building damage are simulated using ground-motion fields that take account of spatial variability and a known fragility curve. These databases are then inverted, applying a standard approach for the derivation of empirical fragility curves, and the difference with the known curve is studied. A parametric analysis is conducted to investigate the impact of various assumptions on the results. By this approach, it is concluded that ground-motion variability leads to flatter fragility curves and that the epistemic uncertainty in the ground-motion prediction equation used can have a dramatic impact on the derived curves. Without dense ground-motion recording networks in the epicentral area empirical curves will remain highly uncertain. Moreover, the use of aggregated damage observations appears to substantially increase uncertainty in the empirical fragility assessment. In contrast, the use of limited randomly-chosen un-aggregated samples in the affected area can result in good predictions of fragility. 相似文献
16.
This paper describes statistical procedures for developing earthquake damage fragility functions. Although fragility curves abound in earthquake engineering and risk assessment literature, the focus has generally been on the methods for obtaining the damage data (i.e., the analysis of structures), and little emphasis is placed on the process for fitting fragility curves to this data. This paper provides a synthesis of the most commonly used methods for fitting fragility curves and highlights some of their significant limitations. More novel methods are described for parametric fragility curve development (generalized linear models and cumulative link models) and non‐parametric curves (generalized additive model and Gaussian kernel smoothing). An extensive discussion of the advantages and disadvantages of each method is provided, as well as examples using both empirical and analytical data. The paper further proposes methods for treating the uncertainty in intensity measure, an issue common with empirical data. Finally, the paper describes approaches for choosing among various fragility models, based on an evaluation of prediction error for a user‐defined loss function. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
17.
Probabilistic fragility functions have been developed for low-rise, reinforced concrete buildings subjected to earthquake triggered slow-moving slides, applying a recently published methodology by the same authors [5] (Fotopoulou and Pitilakis, 2012). We performed an extensive numerical parametric study considering different idealized slope configurations, soil and geological settings, as well as distances of the structure to the slope's crest and foundation typologies. Various features of the structural damage are explored, highlighting trends on the building's behavior to the permanent co-seismic slope deformations. The proposed generalized probabilistic fragility curves have been developed as a function of the expected outcrop peak ground acceleration (PGA) as provided by modern seismic codes, i.e. EC8, or the induced permanent slope ground displacements (PGD) for different slope angles, water table level and soil type, foundation typology and seismic design code. Detailed sensitivity analyses of the above parameters, reveal their relative importance for the vulnerability analysis and the quantitative risk assessment of low-rise RC buildings subjected to earthquake triggered slow-moving slides. 相似文献
18.
Elkhayam M. Dorra Peter J. Stafford Ahmed Y. Elghazouli 《Bulletin of Earthquake Engineering》2013,11(4):1217-1257
The Egyptian economy and culture are centralized in the Greater Cairo region. Thus, it is essential that the built environment is able to withstand the possible earthquake events that may occur, and to continue to operate and function. Failure to do so would result in significant economic losses. This study presents the latter stages of a multi-tiered probabilistic earthquake loss estimation model for Greater Cairo and builds upon previous studies of the seismic hazard. In order to assess possible damage to the built environment, and the resulting economic losses, the vulnerability of the built environment is first evaluated. Through the use of satellite images, Egypts building census, previous studies and field surveys, a building-stock inventory is compiled. This building inventory is classified according to structural type and height, and is geocoded by district. Using existing fragility curves, the vulnerability of the building stock is assessed. In addition, the vulnerability of both the electricity and natural gas networks are assessed, through the use of fragility curves, cut sets and an evaluation of the supply networks. Based on the assessment of direct losses, the losses associated with building damage far exceed those associated with the considered network infrastructure. A macro-economic model is developed that takes into account damage to the built environment and provides estimates of indirect economic losses, as well as enabling the identification of the optimal recovery process. Using this model, it is shown that the indirect losses can exceed direct losses for extreme scenarios where the economy is brought to a near standstill. The framework developed and presented herein can be extended to include more networks, and is also applicable to other regions. 相似文献
19.
Zhao Chunfeng Zhou Lei Huang Shenjiang Gautam Avinash 《Bulletin of Earthquake Engineering》2022,20(11):6047-6074
In general, historical earthquake events have shown that a strong mainshock might trigger several aftershocks, which can cause additional damage and seismic risk to the structures. This work tries to investigate the aftershock duration on seismic fragility of the shield building in consideration of initial damage. For this purpose, a three-dimensional finite element model of shield building is established using a concrete damage plastic model. A series of mainshock-aftershock sequences with different durations are selected and scaled to match the target spectrum. A damage ratio of tensile damage is developed to evaluate the additional damage caused by mainshock and aftershocks. Aftershocks with three durations, namely, 20 s, 40 s, and 60 s, are used to study the effect of initial damage levels and aftershock durations on the accumulative damage and seismic fragility of the shield building. The results indicate that those aftershocks with longer durations may wreak more worse cumulative damage to the post-mainshock damaged structure and significantly affect the probability of exceedance. It is also indicated that the initial damage levels have a significant impact on the fragility curves of the shield building. This work can directly incorporate the influence of mainshock-damaged states into the fragility assessment for Nuclear Power Plant.
相似文献20.
Earthquake damage data is of vital importance both as an indicator of the likely performance of buildings in future earthquakes,
as well as for the calibration of existing theoretical-analytical models regarding building vulnerability. The analysis of
damage data collected shortly after the August 14, 2003 Lefkada Island, Greece earthquake revealed the higher vulnerability
of masonry buildings vis-à-vis all other building typologies on the island. However, promising means in strengthening the
existing masonry stock emerge, when considering the improved performance of buildings of a dual-system of stone-masonry and
timber frame – a construction practice uniquely adopted in the island. Based on the parameterless seismic intensity scale
(psi) proposed by Spence et al. (1991) a set of preliminary vulnerability curves for the typologies of the island’s buildings are proposed. 相似文献