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1.
The main goals of this article are to analyze the use of simplified deterministic nonlinear static procedures for assessing the seismic response of buildings and to evaluate the influence that the uncertainties in the mechanical properties of the materials and in the features of the seismic actions have in the uncertainties of the structural response. A reinforced concrete building is used as a guiding case study. In the calculation of the expected spectral displacement, deterministic nonlinear static methods are simple and straightforward. For not severe earthquakes these approaches lead to somewhat conservative but adequate results when compared to more sophisticated procedures involving nonlinear dynamic analyses. Concerning the probabilistic assessment, the strength properties of the materials, concrete and steel, and the seismic action are considered as random variables. The Monte Carlo method is then used to analyze the structural response of the building. The obtained results show that significant uncertainties are expected; uncertainties in the structural response increase with the severity of the seismic actions. The major influence in the randomness of the structural response comes from the randomness of the seismic action. A useful example for selected earthquake scenarios is used to illustrate the applicability of the probabilistic approach for assessing expected damage and risk. An important conclusion of this work is the need of broaching the fragility of the buildings and expected damage assessment issues from a probabilistic perspective.  相似文献   

2.
This paper is a presentation of an European project called RISK-UE, entitled: “An advanced approach to earthquake risk scenarios with applications to different European towns”. It gives the origin, the objectives and the organisation of the project, together with the content of the different workpackages comprising methodological aspects: different features of European town, seismic hazard, urban system exposure, vulnerability of current, historical and monumental buildings, vulnerability of lifelines and essential facilities, seismic risk scenario, with an application to the seven following cities: Barcelona, Bitola, Bucharest, Catania, Nice, Sofia and Thessaloniki. These studies were realized in close relation with the decisionmakers of these cities, in order that they implement Risk Management Plans and Plans of Action to effectively reduce seismic risk.  相似文献   

3.
A study on damage scenarios for residential buildings in Catania city   总被引：2，自引：0，他引：2  
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.
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   

5.
A vulnerability analysis of some historical and monumental buildings in the city of Málaga is presented in this paper. More than twenty of these monuments were severely damaged or completely destroyed due to the large earthquake (I max = VIII–IX) occurred in the Málaga region in October 1680. The vulnerability index methodology has been used in this paper. This technique is based on statistical data from seismic damage caused to Italian monuments for the past 30?years. For each building, vulnerability curves have been obtained and damage grades have been estimated. A comparison has been carried out between the expected damage grades and the damage observed from past earthquakes, in order to check the feasibility of applying this methodology to Spanish monuments. This comparison has been possible due to the fact that detailed seismic damage information exists for monuments in the city of Málaga that still exist today, which is a very uncommon case in Spain. Results show a good consistency between expected and observed damage, especially for the churches type. Two seismic scenarios have been proposed for the city centre, one deterministic and one probabilistic, where 54 historical and modern buildings have been analyzed. Both scenarios show worrying results, especially for the types of churches, chapels and towers, where expected high probabilities of suffering very heavy damage or even collapse have been obtained. It is highly recommended to take the necessary measures, in the hope of trying to avoid the possible damage that can be expected from future earthquakes.  相似文献   

6.
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   

7.
城市震害预测中设定地震的确定问题   总被引：2，自引：0，他引：2  
韩竹军  黄昭 《中国地震》1999,15(4):349-356
提出了一个确定震害预测中设定地震的方法,包括：确定贡献量最大的潜在震源区、潜在震源区内贡献量最大的震级档和设定地震的构造位置等。以福建省泉州市为例,获得５０年超赵概率６３％、１０％和２％等３个概率水平下的设定地震。本文给出的设定地震方法纵使了确定论方法和概率论方法的优点,有助于地震危险性分析方法的发展。  相似文献   

8.
The Capacity Spectrum Based Method developed in the framework of the European project Risk-UE has been applied to evaluate the seismic risk for the city of Barcelona, Spain. Accordingly, four damage states are defined for the buildings, the action is expressed in terms of spectral values and the seismic quality of the buildings, that is, their vulnerability, is evaluated by means of capacity spectra. The probabilities of the damage states are obtained considering a lognormal probability distribution. The most relevant seismic risk evaluation results obtained for Barcelona, Spain, are given in the article as scenarios of expected losses.  相似文献   

9.
The objectives of the Istanbul Seismic Risk Mitigation and Emergency Preparedness Project are to improve Istanbul’s preparedness for a potential earthquake. Within this framework “Risk Assessment of Cultural Heritage Buildings” was designed to address the vulnerability of cultural assets, specifically buildings with global cultural heritage value. One of the components of the project was the vulnerability and risk assessment of 170 historical buildings. After a discussion of the choice of the most appropriate earthquake scenario, the methodology used for assessing the effects of local site conditions on the seismic performance of selected cultural heritage buildings is presented. The purpose is to estimate the earthquake characteristics on the ground surface based on the earthquake characteristics on the engineering bedrock outcrop obtained from the probabilistic and deterministic hazard studies. The site specific elastic design spectra for each site are then further manipulated to obtain site specific non linear displacement spectra, so that these can be directly compared with capacity curves for the buildings obtained by using plasticity based limit state analysis. The procedure for obtaining the capacity curves is described and the choice of the most appropriate level of ductility and the equivalent reduction coefficient are discussed. A procedure to evaluate performance points and to define safety factors based on lateral acceleration, drift or expected damage level, is presented. The process of arriving at a risk evaluation and hence recommendation for strengthening or otherwise, is finally highlighted with respect to two comparable case studies.  相似文献   

10.
基于皖东北地区多层砌体校舍抗震性能调查,结合汶川地震的震害,对皖东北地区中小学多层砌体校舍的特点、抗震能力进行阐述,运用易损性概率分析法对所调查的校舍进行震害预测,并提出了相应的防震减灾对策,以期为该地区校舍安全工程提供参考.  相似文献   

11.
Earthquake loss estimation for the New York City Metropolitan Region   总被引：1，自引：0，他引：1  
This study is a thorough risk and loss assessment of potential earthquakes in the NY–NJ–CT Metropolitan Region. This study documents the scale and extent of damage and disruption that may result if earthquakes of various magnitudes occurred in this area. Combined with a detailed geotechnical soil characterization of the region, scenario earthquakes were modeled in HAZUS (Hazards US), a standardized earthquake loss estimation methodology and modeling program. Deterministic and probabilistic earthquake scenarios were modeled and simulated, which provided intensities of ground shaking, dollar losses associated with capital (the building inventory) and subsequent income losses. This study has also implemented a detailed critical (essential) facilities analysis, assessing damage probabilities and facility functionality after an earthquake. When viewed in context with additional information about regional demographics and seismic hazards, the model and results serve as a tool to identify the areas, structures and systems with the highest risk and to quantify and ultimately reduce those risks.  相似文献   

12.
The paper describes the earthquake performance assessment of two historical buildings located in Istanbul exposed to a Mw = 7+ earthquake expected to hit the city and proposes solutions for their structural rehabilitation and/or strengthening. Both buildings are unreinforced clay brick masonry (URM) structures built in 1869 and 1885, respectively. The first building is a rectangular-shaped structure rising on four floors. The second one is L-shaped with one basement and three normal floors above ground. They survived the 1894, Ms = 7.0 Istanbul Earthquake, during which widespread damage to URM buildings took place in the city. Earthquake ground motion to be used in performance assessment and retrofit design is determined through probabilistic and deterministic seismic hazard assessment. Strength characteristics of the brick walls are assessed on the basis of Schmidt hammer test results and information reported in the literature. Dynamic properties of the buildings (fundamental vibration periods) are measured via ambient vibration tests. The buildings are modelled and analyzed as three-dimensional assembly of finite elements. Following the preliminary assessment based on the equivalent earthquake loads method, the dynamic analysis procedure of FEMA 356 (Pre-standard and commentary for the seismic rehabilitation of buildings, American Society of Civil Engineers, Reston, 2000) and ASCE/SEI 41-06 (Seismic rehabilitation of existing buildings, American Society of Civil Engineers, Reston, 2007) is followed to obtain dynamic structural response of the buildings and to evaluate their earthquake performance. In order to improve earthquake resistance of the buildings, reinforced cement jacketing of the main load carrying walls and application of fiber reinforced polymer bands to the secondary walls are proposed.  相似文献   

13.
The vulnerability index method, in its version developed in the framework of the European project Risk-UE, has been adapted and applied in this article, to evaluate the seismic risk for the city of Barcelona (Spain) through a GIS based tool. According to this method, which defines five damage states, the action is expressed in terms of the macroseismic intensity and the seismic quality of the buildings by means of a vulnerability index. The probabilities of damage states are obtained considering a binomial or beta-equivalent probability distribution. The most relevant seismic risk evaluation results obtained, for current buildings and monuments of Barcelona, are given in the article as scenarios of expected losses.  相似文献   

14.
Recent earthquakes such as the MJMA 7.2 Hyogo-ken Nambu earthquake and the M 7.4 Kocaeli earthquake demonstrate once again the need to include detailed soil investigation into hazard evaluation, that is the need of microzonation. Seismic hazard assessment evaluated at a regional scale generally does not consider soil effects but only in a limited way using an attenuation law that can be ‘soft soil’ or ‘rock’. However, the relevant role of seismic hazard in the assessment of seismic coefficients for the definition of the actions in seismic codes must be properly considered. That is to say, the level of protection of buildings is proportional to a definite level of hazard (generally considered to be the ground motion with 10% probability of exceedence in 50 years). When a microzonation is performed, this criterion cannot be ignored, therefore, a clear linkage must be established between hazard (regional scale) and microzonation. The crucial point is represented by the reference motion (or input motion) to be used for site effects analysis, that must be compatible with the regional seismic hazard. In this paper, three different approaches for reference motion evaluation are analysed: probabilistic; stochastic; and deterministic. Through the case history of Fabriano microzonation the three approaches are compared. It is shown that each approach presents advantages and disadvantages with respect to the others. For example, the probabilistic approach (the reference motion is directly derived from the expected response spectra for a given return period) is linked with hazard, but produces an overestimation in short periods range, while the deterministic approach correctly simulates the wave propagation, but it ends with a kind of conditional probability. Until now, clear criteria to choose the right approach do not appear to exist and the expert experience is of fundamental importance.  相似文献   

15.
The aim of this paper is to adjust behaviour models for each class of structure for vulnerability assessment by using ambient vibration. A simple model based on frequencies, mode shapes and damping, taken from ambient vibrations, allows computation of the response of the structures and comparison of inter‐storey drifts with the limits found in the literature for the slight damage grade, considered here as the limit of elastic behaviour. Two complete methodologies for building fragility curves are proposed: (1) using a multi‐degree of freedom system including higher modes and full seismic ground‐motion and (2) using a single‐degree of freedom model considering the fundamental mode f0 of the structure and ground‐motion displacement response spectra SD(f0). These two methods were applied to the city of Grenoble, where 60 buildings were studied. Fragility curves for slight damage were derived for the various masonry and reinforced concrete classes of buildings. A site‐specific earthquake scenario, taking into account local site conditions, was considered, corresponding to an ML = 5.5 earthquake at a distance of 15 km. The results show the benefits of using experimental models to reduce variability of the slight damage fragility curve. Moreover, by introducing the experimental modal model of the buildings, it is possible to improve seismic risk assessment at an overall scale (the city) or a local scale (the building) for the first damage grade (slight damage). This level of damage, of great interest for moderate seismic‐prone regions, may contribute to the seismic loss assessment. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   

16.
As a result of population growth and consequent urbanization, the number of high‐rise buildings is rapidly growing worldwide resulting in increased exposure to multiple‐scenario earthquakes and associated risk. The wide range in frequency contents of possible strong ground motions can have an impact on the seismic response, vulnerability and limit states definitions of RC high‐rise wall structures. Motivated by the pressing need to derive more accurate fragility relations to be used in seismic risk assessment and mitigation of such structures, a methodology is proposed to obtain reliable, Seismic Scenario‐Structure‐Based (SSSB) definitions of limit state criteria. A 30‐story wall building, located in a multi‐seismic scenario study region, is utilized to illustrate the methodology. The building is designed following modern codes and then modeled using nonlinear fiber‐based approach. Uncertainty in ground motions is accounted for by the selection of forty real earthquake records representing two seismic scenarios. Seismic scenario‐based building local response at increasing earthquake intensities is mapped using Multi‐Record Incremental Dynamic Analyses (MRIDAs) with a new scalar intensity measure. Net Inter‐Story Drift (NISD) is selected as a global damage measure based on a parametric study involving seven buildings ranging from 20 to 50 stories. This damage measure is used to link local damage events, including shear, to global response under different seismic scenarios. While the study concludes by proposing SSSB limit state criteria for the sample building, the proposed methodology arrives at a reliable definition of limit state criteria for an inventory of RC high‐rise wall buildings under multiple earthquake scenarios. Copyright © 2016 John Wiley & Sons, Ltd.  相似文献   

17.
利用2017年8月9日精河6.6级地震后获取的高分辨率无人机影像，对叶里斯南也肯村153栋房屋进行结构分类和震害解译，获取研究区内土木结构、砖木结构、砖混结构、框架结构4种类型房屋数量及震害特征，并依据解译结果计算每种结构房屋平均震害指数。由于研究区内砖木结构、砖混结构、框架结构房屋数量偏少，房屋内部的震害难以用无人机影像识别，这3类房屋的震害解译结果与现场调查结果相比差别较大，而土木结构房屋平均震害指数及所对应的地震烈度结果与现场调查结果基本一致，表明无人机影像可为房屋震害定量评估提供重要参考。  相似文献   

18.
基于无人机影像的九寨沟地震建筑物震害定量评估   总被引：1，自引：0，他引：1  
利用2017年8月8日九寨沟7.0级地震震后获取的无人机影像,结合地面震害调查资料,分析各类建筑物震害特征,建立建筑物震害无人机遥感解译标志;选取地震灾区漳扎镇(部分区域)和荷叶寨2个区域作为研究区,进行了无人机遥感建筑物震害提取,基于遥感震害指数进行了震害定量评估,并与现场建筑物震害调查统计结果进行了比较验证。结果显示,遥感解译建筑物震害与实际震害程度相吻合,表明利用震后快速获取的高分辨率无人机影像,可以较为准确地识别建筑物震害,进而为地震灾害定量评估和应急救援辅助决策提供重要参考。  相似文献   

19.
On March 4, 1977, an earthquake with a moment magnitude M w 7.4 at a hypocentral depth of 94 km hit the Vrancea region (Romania). In Bucharest alone, the earthquake caused severe damage to 33,000 buildings while 1,424 people were killed. Under the umbrella of the SAFER project, the city of Bucharest, being one of the larger European cities at risk, was chosen as a test bed for the estimation of damage and connected losses in case of a future large magnitude earthquake in the Vrancea area. For the conduct of these purely deterministic damage and loss computations, the open-source software SELENA is applied. In order to represent a large event in the Vrancea region, a set of deterministic scenarios were defined by combining ranges of focal parameters, i.e., magnitude, focal depth, and epicentral location. Ground motion values are computed by consideration of different ground motion prediction equations that are believed to represent earthquake attenuation effects in the region. Variations in damage and loss estimates are investigated through considering different sets of building vulnerability curves (provided by HAZUS-MH and various European authors) to characterize the damaging behavior of prevalent building typologies in the city of Bucharest.  相似文献   

20.
This paper introduces the characteristics of earthquake disasters in the 2013 Urumqi MS5.1 and the 2015 Pishan MS6.5 earthquakes, which are directly beneath the cities. Based on the discussion on regional tectonic background, site conditions, seismic fortification level of buildings, we preliminarily analyzed the causes of earthquake disaster for buildings caused by the two earthquakes.Finally,we give some advice on earthquake resistance for residential buildings and earthquake damage prevention in Xinjiang.  相似文献   

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