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1.
Fragility curves constitute the cornerstone in seismic risk evaluations and performance-based earthquake engineering. They describe the probability of a structure to experience a certain damage level for a given earthquake intensity measure, providing a relationship between seismic hazard and vulnerability. In this paper a numerical approach is applied to derive fragility curves for tunnel shafts built in clays, a component that is found in several critical infrastructure such as urban metro networks, airport facilities or water and waste water projects. The seismic response of a representative tunnel shaft is assessed using tridimensional finite difference non-linear analyses carried out with the program FLAC3D, under increasing levels of seismic intensity. A hysteretic model is used to simulate the soil non-linear behavior during the seismic event. The effect of soil conditions and ground motion characteristics on the soil-structure system response is accounted for in the analyses. The damage is defined based on the exceedance of the concrete wall shaft capacity due to the developed seismic forces. The fragility curves are estimated in terms of peak ground acceleration at a rock or stiff soil outcrop, based on the evolution of damage with increasing earthquake intensity. The proposed fragility models allows the characterization of the seismic risk of a representative tunnel shaft typology and soil conditions considering the associated uncertainties, and partially fill the gap of data required in performing a risk analysis assessment of tunnels shafts. 相似文献
2.
Simulation of strong earthquake characteristics of a scenario earthquake (MS7.5) based on the enlightenment of 2022 MS6.9 earthquake in Menyuan 
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下载免费PDF全文 The Menyuan area is an important transportation hub in the Hexi Corridor. The Menyuan MS6.9 earthquake that occurred on January 8, 2022 had a major impact on the local infrastructure and transportation of this region. Due to the high possibility of similar strong earthquakes occurring in this area in the future, preliminary assessment of the seismic intensity characteristics of destructive earthquakes in this region is essential for effective disaster control. This paper uses the empirical Green′s function (EGF) method as a numerical simulation tool to predict the ground motion intensity of Datong Autonomous County under the action of the scenario earthquake (MS7.5). Seismic records of aftershocks of the 2016 Menyuan MS6.4 earthquake were used as Green’s functions for this simulation. The uncertainties associated with various source parameters were considered, and 36 possible earthquake scenarios were simulated to obtain 72 sets of horizontal ground motions in Datong County. The obtained peak ground acceleration (PGA) vs. time histories of the horizontal ground motion were screened using the attenuation relationships provided by the fifth-edition of China's Seismic Ground Motion Parameter Zoning Map and the NGA-West2 dataset. Ultimately, 32 possible acceleration-time histories were selected for further analysis. The screened PGA values ranged from 78.8 to 153 cm/s2. The uncertainty associated with the initial rupture point was found to greatly affect the results of the earthquake simulation. The average acceleration spectrum of the selected acceleration-time history exceeded the expected spectrum of a intermediate earthquake, which means that buildings in Datong County might sustain some damage should the scenario earthquake occur. This research can provide reliable ground motion input for urban earthquake damage simulation and seismic design in Datong County. Growing the dataset of small earthquakes recorded in this region will facilitate the large-scale simulation of ground motions under different earthquake scenarios. 相似文献
3.
The main purpose of this study is to obtain the damage scenario for residential buildings in the occurrence of a destructive earthquake (M = 7+) in the city area of Catania, Eastern Sicily, and to illustrate the comparative performance of two alternative methods used for this purpose. The methods are representative of two different approaches to estimating the seismic vulnerability of structures, i.e., an empirical approach based on statistical score assignments (widely used in Italy and other countries) and a more recent, mechanical approach that uses displacement limit states associated with well-defined thresholds of structural damage. A special concern for seismic vulnerability in Catania is caused by the fact that earthquake design norms were enforced in its municipal area only since 1981. We emphasise some typical problems encountered in earthquake scenario work, such as the difficulty of assembling a reliable building inventory, and the uncertainties inherent in the vulnerability assessments through different probabilistic assumptions. Different criteria for the representation of damage are applied and discussed. It is shown that the main scenarios obtained by the two methods are in reasonable agreement, provided a suitable percentile level for damage is chosen in the statistical score assignment approach. 相似文献
4.
Earthquake-resistant design and seismic analysis often require the earthquake action to be represented in the form of acceleration time-histories. Real accelerograms can be selected based on matching an earthquake scenario, defined by magnitude and distance, and scaled if necessary. The scaled accelerograms should reflect the hazard in terms of the parameters that characterise the inelastic demand on structures, including response spectral ordinates, duration and energy content. In order to maintain realistic ground motions, the scaling factors should not differ greatly from unity. It is found that in many cases, where the hazard is influenced by more than one seismic source, it is impossible to define a single earthquake scenario that is compatible with the results of probabilistic seismic hazard assessment. Even if a hazard-consistent scenario can be defined, there are difficulties encountered in using the results to select and scale real accelerograms. 相似文献
5.
邢台地区设定地震事件烈度影响 总被引：1，自引：1，他引：0
通过邢台地区历史地震烈度资料分析,得到该地区烈度—频率灾害曲线及地震风险。以地震地质资料理论为基础,结合河北省城市活断层探测成果、地壳结构等资料,确定2个设定地震事件。采用复合震源模型,模拟合成强地面运动,并基于强地面运动模拟结果,分析邢台地区地震影响烈度,为今后该地区建筑物抗震设防、避难场所选址、震后救援以及地震保险风险评估提供参考依据。 相似文献
6.
The Global Earthquake Vulnerability Estimation System (GEVES): an approach for earthquake risk assessment for insurance applications 总被引：4，自引：0，他引：4
Robin Spence Emily So Sarah Jenny Hervé Castella Michael Ewald Edmund Booth 《Bulletin of Earthquake Engineering》2008,6(3):463-483
For the insurance and reinsurance industries, earthquake loss estimation is crucial not only to adequately price its product
but also to manage the accumulation risk in the face of the ever-increasing exposure in highly seismic regions. Changes in
the built environment and a continuously evolving earthquake science make it a necessity for the industry to constantly refine
earthquake loss estimation models. In particular, it has been recognized for a long time that the vulnerability of buildings
to ground shaking is a key parameter in any earthquake risk model. Current methods tend either to rely on the limited historical
damage and loss data or on the numerical simulation of the response of individual buildings to the ground-shaking produced
by earthquakes. Although both methods have their advantages and pitfalls, we are proposing here a simple solution, using transparent
input data, that can be realistically used for the needs of the insurance and reinsurance industry, whether detailed information
about the insured structures is available or not. The resulting product is known as GEVES (Global Earthquake Vulnerability
Estimation System). It is primarily intended for evaluating the mean damage ratio (MDR) suffered by a portfolio of buildings
classified by use, under the action of a given earthquake scenario (i.e. an earthquake of given size at a given distance from
the portfolio of buildings). A key assumption was that macroseismic intensity rather than spectral displacement would be the
basis of loss estimation. The paper describes the model with emphasis on its structure and the justification for the assumptions
made. In addition to a new set of earthquake vulnerability functions, the paper also provides recommendations on some aspects
of the earthquake hazard, in particular about how to define macroseismic intensity at the site of interest, for a given earthquake
scenario. This paper also discusses validation of the GEVES model against calculated vulnerability approaches, and the treatment
of uncertainty within the model. 相似文献
7.
A methodology for seismic microzonation and earthquake damage scenarios may be considered as composed of two stages. In the first stage, microzonation maps with respect to estimated earthquake characteristics on the ground surface are generated for an investigated urban area. The effects of local geological and geotechnical site conditions are taken into account based on site characterization with respect to representative soil profiles extending down to the engineering bedrock. 1D site response analyses are performed to calculate earthquake characteristics on the ground surface using as many as possible, hazard compatible real acceleration time histories. In the second stage, vulnerability of buildings and pipeline systems are estimated based on site-specific ground motion parameters. A pilot study is carried out to evaluate seismic damage in a district in Istanbul, Turkey. The results demonstrate the significance of site characterization and site response analysis in calculating the earthquake characteristics on the ground surface in comparison to simplified empirical procedures. 相似文献
8.
Carlo Del Gaudio Paolo Ricci Gerardo M. Verderame Gaetano Manfredi 《Bulletin of Earthquake Engineering》2016,14(10):2643-2678
A damage scenario based on observational data collected in L’Aquila Municipality after the 6th April 2009 earthquake is compared with a predicted damage scenario derived from the application of a simplified analytical method for seismic vulnerability assessment of Reinforced Concrete (RC) buildings at large scale. The observational damage scenario is derived from a database of 131 RC buildings located in the Municipality of L’Aquila, which after the 2009 earthquake were subjected to post-earthquake usability assessment procedure. The simplified analytical approach adopted is based on the Capacity Spectrum Method to evaluate seismic capacity at different Damage States (DSs) based on the displacement capacity of structural and non-structural elements. DSs and the corresponding displacement capacity are defined through the interpretation of the observational-based DSs provided by the European Macroseismic Scale EMS-98. Data predicted by the adopted methodology are in good agreement with the observed damage distribution. The observed damage scenario is also compared with predicted scenarios derived from other methodologies from literature. 相似文献
9.
This paper presents a method for seismic vulnerability analysis of bridge structures based on vector-valued intensity measure(v IM), which predicts the limit-state capacities efficiently with multi-intensity measures of seismic event. Accounting for the uncertainties of the bridge model, ten single-bent overpass bridge structures are taken as samples statistically using Latin hypercube sampling approach. 200 earthquake records are chosen randomly for the uncertainties of ground motions according to the site condition of the bridges. The uncertainties of structural capacity and seismic demand are evaluated with the ratios of demand to capacity in different damage state. By comparing the relative importance of different intensity measures, Sa(T1) and Sa(T2) are chosen as v IM. Then, the vector-valued fragility functions of different bridge components are developed. Finally, the system-level vulnerability of the bridge based on v IM is studied with DunnettSobel class correlation matrix which can consider the correlation effects of different bridge components. The study indicates that an increment IMs from a scalar IM to v IM results in a significant reduction in the dispersion of fragility functions and in the uncertainties in evaluating earthquake risk. The feasibility and validity of the proposed vulnerability analysis method is validated and the bridge is more vulnerable than any components. 相似文献
10.
Masanobu Shinozuka George Deodatis Ruichong Zhang Apostolos S. Papageorgiou 《Soil Dynamics and Earthquake Engineering》1999,18(3):182
State of the art in modeling, synthetics, statistical estimation, and engineering applications of strong ground motion is reported in this paper. In particular, models for earthquake wave motion are presented, in which uncertainties both in the earth medium and the seismic source are taken into consideration. These models can be used to synthesize realistic strong earthquake ground motion, specifically near-field ground motion which is quite often not well recorded in real earthquakes. Statistical estimation techniques are also presented so that the characteristics of spatially-correlated earthquake motion can be captured and consequently used in investigating the seismic response of such large scale structures as pipelines and long-span bridges. Finally, applications of synthesized strong ground motion in a variety of engineering fields are provided. Numerical examples are shown for illustration. 相似文献
11.
Vincenzo Convertito Iunio Iervolino Aldo Zollo Gaetano Manfredi 《Soil Dynamics and Earthquake Engineering》2008,28(6):492-505
The development and implementation of an earthquake early warning system (EEWS), both in regional or on-site configurations can help to mitigate the losses due to the occurrence of moderate-to-large earthquakes in densely populated and/or industrialized areas. The capability of an EEWS to provide real-time estimates of source parameters (location and magnitude) can be used to take some countermeasures during the earthquake occurrence and before the arriving of the most destructive waves at the site of interest. However, some critical issues are peculiar of EEWS and need further investigation: (1) the uncertainties on earthquake magnitude and location estimates based on the measurements of some observed quantities in the very early portion of the recorded signals; (2) the selection of the most appropriate parameter to be used to predict the ground motion amplitude both in near- and far-source ranges; (3) the use of the estimates provided by the EEWS for structural engineering and risk mitigation applications.In the present study, the issues above are discussed using the Campania–Lucania region (Southern Apennines) in Italy, as test-site area. In this region a prototype system for earthquake early warning, and more generally for seismic alert management, is under development. The system is based on a dense, wide dynamic accelerometric network deployed in the area where the moderate-to-large earthquake causative fault systems are located.The uncertainty analysis is performed through a real-time probabilistic seismic hazard analysis by using two different approaches. The first is the Bayesian approach that implicitly integrate both the time evolving estimate of earthquake parameters, the probability density functions and the variability of ground motion propagation providing the most complete information. The second is a classical point estimate approach which does not account for the probability density function of the magnitude and only uses the average of the estimates performed at each seismic station.Both the approaches are applied to two main towns located in the area of interest, Napoli and Avellino, for which a missed and false alarm analysis is presented by means of a scenario earthquake: an M 7.0 seismic event located at the centre of the seismic network.Concerning the ground motion prediction, attention is focused on the response spectra as the most appropriate function to characterize the ground motion for earthquake engineering applications of EEWS. 相似文献
12.
A GIS-oriented procedure that may partially illuminate the consequences of a possible earthquake is presented in two main steps (seismic microzonation and vulnerability steps) along with its application in Tabriz (a city in NW Iran). First, the detailed geological, geodetical, geotechnical and geophysical parameters of the region are combined using an Analytic Hierarchy Process (AHP) and a deterministic near-field earthquake of magnitude 7 in the North Tabriz Fault is simulated. This simulation provides differing intensities of ground shaking in the different districts of Tabriz. Second, the vulnerability of buildings, human losses and basic resources for survivors is estimated in district two of the city based on damage functions and relational analyses. The results demonstrate that 69.5% of existing buildings are completely destroyed, and the rate of fatalities is approximately 33% after a nighttime scenario. Finally, the same procedure was applied to an actual earthquake (first event on the 11th of August, 2012 of the Ahar twin earthquakes) to validate the presented model based on two aspects: (1) building damages and (2) seismic intensity. 相似文献
13.
14.
基于三维GIS技术的地震灾情场景模拟系统 总被引：4，自引：0，他引：4
设计并实现了基于三维GIS技术的地震灾情场景模拟系统。根据现场救援工作的特点和需求,对基于基础地理信息数据的自动三维建模方法和场景生成技术进行了研究,建立了基于地震动影响场和结构易损性的地震灾情场景模型;基于ArcGISEngine开发组件,实现了灾前、灾后场景的自动生成和直观显示,实现了整体破坏情况分析、重点搜索区域判定、关键目标震害与属性查询等灾情分析和辅助决策功能。该系统以震区基础地理信息数据和地震基本参数作为数据源,可以在获得地震基本参数之后快速地估计和分析震区建筑结构的破坏及其空间分布情况,预判重点搜索救援区域,为应急指挥决策和救援行动提供有效的支持,适合在现场救援工作中实际应用。 相似文献
15.
Epistemic uncertainties can be classified into two major categories: parameter and model. While the first one stems from the difficulties in estimating the values of input model parameters, the second comes from the difficulties in selecting the appropriate type of model. Investigating their combined effects and ranking each of them in terms of their influence on the predicted losses can be useful in guiding future investigations. In this context, we propose a strategy relying on variance-based global sensitivity analysis, which is demonstrated using an earthquake loss assessment for Pointe-à-Pitre (Guadeloupe, France). For the considered assumptions, we show: that uncertainty of losses would be greatly reduced if all the models could be unambiguously selected; and that the most influential source of uncertainty (whether of parameter or model type) corresponds to the seismic activity group. Finally, a sampling strategy was proposed to test the influence of the experts’ weights on models and on the assumed coefficients of variation of parameter uncertainty. The former influenced the sensitivity measures of the model uncertainties, whereas the latter could completely change the importance rank of the uncertainties associated to the vulnerability assessment step. 相似文献
16.
针对目前仅以城市单体为对象研究城市地震灾害脆弱性，而忽视城市内部不同区域间存在特征差异的问题，选择威海市区作为研究对象，将研究范围细化至22个街道（镇），建立城市小区域地震灾害脆弱性评价模型。从人口、经济、建筑物和生命线系统4个方面选取17个指标构建城市地震脆弱性评价指标体系，应用主客观结合的三角模糊熵法和改进TOPSIS模型，计算出研究区域的相对贴近程度并进行排序，将威海市区划分为4个不同脆弱性等级。结果表明:改进TOPSIS模型能够从整体上对城市地震灾害脆弱性进行评级分区，为城市内部有针对性的制定防震减灾策略提供一个全新的思路。 相似文献
17.
四川汶川8级大地震灾害损失快速评估研究/ 总被引：18，自引：2，他引：16
地震发生之后,在没有开展地震现场调查之前,迅速对地震造成的人员伤亡、直接经济损失等进行评估,对地震应急救援决策非常重要．本文叙述了基于宏观经济指标的地震灾害损失评估方法,根据我国1989——2004年地震现场灾害损失调查资料重新确定的地震易损性模型,给出了汶川8级大地震发生后依据估计的经验地震烈度图得到的地震损失快速评估结果,并与依据现场调查确定的地震烈度分布图给出的地震损失评估结果进行了比较．表明根据近20年我国实际地震震例确定的地震易损性模型具有较好的适用性,损失评估结果的最大不确定来自于对地震影响场的估计． 相似文献
18.
Seismic fragility can be assessed by conducting incremental dynamic analysis (IDA). This study extends the current conditional mean spectrum (CMS)-based record selection approach for IDA by taking into account detailed seismic hazard information. The proposed method is applied to conventional wood-frame houses in Canada, across which dominant earthquake scenarios and associated hazard levels vary significantly. Effects due to different seismic environments, site conditions, CMS-based record selection methods, and house models are investigated by comparing various seismic fragility models. Moreover, relative impact of the key characteristics is evaluated in terms of seismic loss curve for a group of wood-frame houses. Importantly, a close examination of regional seismic hazard characteristics using seismic hazard curve and seismic deaggregation facilitates the deeper understanding of the impact of ground motion characteristics on seismic fragility. A comprehensive and systematic assessment of key uncertainties associated with seismic fragility is provided. 相似文献
19.
Fast assessment of earthquake loss and its application to the 2008 MS8.0 Wenchuan earthquake 下载免费PDF全文
下载免费PDF全文 The paper introduces firstly the seismic loss assessment method based on macro-economic indicators and new vulnerability models determined by the data from the on-site damage and loss survey to earthquakes occurred in China during the last two decades. The fast assessment for the 2008 Wenchuan earthquake with MS8.0 is given based on an empirical intensity attenuation relationship. Compared with the assessment based on the practical seismic intensity map of the event according to the on-site investigation, the result demonstrates the usability of the seismic vulnerability models introduced in the paper. In addition, it is indicated that the main uncertainty of losses in the fast loss assessment comes from the uncertainty of the estimation of seismic ground motion. 相似文献
20.
The objective of this paper is to describe the lessons learned and actions that have been taken related to the seismic design
of bridge structures after the Chi-Chi, Taiwan earthquake. Much variable near-fault ground motion data was collected from
the rupture of Chelungpu fault during the Chi-Chi earthquake, allowing the seismic response of bridge structures subjected
to these near-fault ground motions to be carefully examined. To study the near-fault ground motion effect on bridge seismic
design codes, a two-level seismic design of bridge structures was developed and implemented. This design code reflects the
near-fault factors in the seismic design forces. Finally, a risk assessment methodology, based on bridge vulnerability, is
also developed to assist in decisions for reducing seismic risk due to failure of bridges.
Director of Center for Research on Earthquake Engineering.
Supported by: the Science Council, Chinese Taipei, under grant no. SC 90-2211-E-002-028. 相似文献