共查询到19条相似文献,搜索用时 140 毫秒
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《地震工程与工程振动》2017,(4)
为了促进桥梁结构地震易损性分析在我国的发展和应用,详细论述了公路桥梁地震易损性分析方法在国内外的研究现状、存在的问题和发展方向。首先,对国内外常用的桥梁地震易损性分析方法进行分类,归纳了每种方法的适用性,总结了桥梁地震易损性研究在我国的发展历程和研究现状;其次,根据采用的参数估计方法的不同,将理论地震易损性函数分为四种类型,介绍了每种易损性函数的建立过程和优缺点。最后,指出了该领域尚且存在的一些问题和有待研究的方向。研究结果表明,易损性分析能很好地考虑桥梁抗震设计中存在的不确定性问题,对基于性能桥梁抗震设计的发展具有重要的意义。 相似文献
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《世界地震工程》2016,(1)
桥梁的地震易损性分析大多数基于桥梁的破坏状态,基于结构性能的易损性分析直接给出结构对应于不同功能等级的失效概率,因此基于性能的易损性分析更具有实用价值。迄今为止,在桥梁领域尚没有基于结构性能的易损性分析,其主要困难在于定义与结构性能水准相适应的量化性能指标。基于结构极限状态定义了钢筋混凝土桥梁的4个性能水准,以目标墩顶漂移率为量化性能指标,提出基于性能的钢筋混凝土桥梁的地震易损性分析方法。由于桥墩是桥梁结构中极易受到破坏且不易更换的构件,因此常通过研究桥墩的易损性来研究桥梁结构的易损性。在地震作用下,隔震装置将会影响桥墩的易损性,但是目前缺少相关研究。以4跨连续钢筋混凝土桥梁为例,采用Open Sees分别建立非隔震桥梁和隔震桥梁的有限元模型,考虑地震动随机性,对两种桥梁进行了基于IDA(增量动力分析方法)的非线性动力时程分析。最后用文中提出的方法分别对非隔震桥梁和隔震桥梁的中墩进行基于性能的地震易损性分析,并形成易损性曲线。对比非隔震桥梁和隔震桥梁中墩的易损性曲线,分析隔震支座对桥墩易损性的影响。 相似文献
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21世纪我国经济急速发展,人口也急剧增长,这也使得地震对人类生命和财产安全造成的威胁更大,结构抗震研究需求日益增加。地震易损性分析技术对于结构破坏和损失预测都有着非同一般的应用价值,因此受到了国内外土木工程抗震界的广泛关注和研究。首先介绍了地震易损性分析的基本概念,具体地论述了用于地震易损性分析的三种方法,同时总结出此三种方法各自的优缺点;其次以RC框架结构为例论述了国内外地震易损性分析领域的研究发展,从上个世纪90年代开始进行了系统的梳理和分析。说明了地震易损性分析在研究过程中由于不确定性的存在而导致对分析结果准确度的影响;最后指出要想得到更接近于真实的易损性分析结果,还需考量易损性分析中的不确定参数,揭示了地震易损性分析研究领域所面临的挑战。 相似文献
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桥梁作为交通中不可或缺的一部分,对其地震易损性进行研究具有现实意义。针对当前桥梁地震易损性分析方法存在准确性待提升的问题,提出基于模糊评定的钢筋混凝土桥梁地震易损性评估模型。以桥梁结构层次、材料层次及边界层几方面为主对桥梁评估过程中的不确定性参数进行分析。以分析结果为依据,考虑到桥梁损失是一个比较模糊的概念,引入模糊数学中的模糊评定方法对桥梁地震易损性进行评估。融合位移下桥梁支座损伤分析、能量下桥墩损伤分析、周期下桥梁结构整体损伤分析,构建可以反映钢筋混凝土桥梁由局部到整体的多层次模糊易损性评估模型。通过实验对所建模型进行验证,结果显示:在纵向只发生轻微破坏,且轻微破坏的概率较小,基本处于完好状态。而在横向,发生轻微破坏的概率较大,甚至还可能发生中等破坏。在地震作用下,桥梁破坏也基本以轻微破坏和中等破坏为主,严重破坏的概率很小。 相似文献
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桥梁在长期服役过程中面临的氯离子侵蚀作用会导致材料性能退化,进而影响桥梁结构的抗震性能。准确评估服役桥梁的抗震性能可以有效保障和提高桥梁结构的安全性,因此开展考虑时变效应的桥梁地震易损性分析非常必要。考虑到地震易损性分析涉及大量的动力时程分析,计算效率很低,故采用高斯过程模型取代耗时的动力时程分析,旨在提高地震易损性分析效率。以一座三跨连续梁桥为例,探究氯离子侵蚀作用下桥墩材料性能的退化规律,建立纵筋、箍筋以及保护层和核心混凝土材料性能退化时变曲线;基于高斯过程模型和联合概率地震需求模型,建立桥梁系统在不同服役年限下的易损性曲线和曲面。结果表明:(1)氯离子侵蚀作用明显降低了桥墩钢筋混凝土材料的强度;(2)氯离子侵蚀作用明显提高了高等级损伤的桥梁地震易损性,结构更容易发生高等级损伤。 相似文献
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《国际地震动态》2018,(10)
随着综合国力迅速提升,我国进行了大规模的公路网络建设,兴建了数以万计的公路桥梁,为整个经济社会的可持续发展提供了有力支撑。然而,国内外历次大地震中有大量公路桥梁发生破坏,这极大地降低了公路交通的通行能力,严重阻碍应急救援工作和城市日常生活。我国是遭受地震灾害最多的国家之一,因此,在我国开展公路桥梁地震易损性研究具有重要的现实意义。本文在对汶川地震公路桥梁调查数据深度挖掘整理和全面归纳总结之基础上,采用多种方法比较系统地研究了当代公路桥梁的地震易损性,还开展了基于公路桥梁震害评定地震烈度的研究,旨在更好地服务于公路桥梁的震害预测和损失评估、震后可恢复性研究、交通系统的地震风险分析,以及应急救灾决策的制定和完善抗震设计理论等工作,从而达到减轻桥梁震害和提高救援效率之目的。论文主要完成了以下工作:(1)针对低烈度区公路桥梁调查数据不完备、遗漏大量基本完好桥梁的实际情况,按照烈度区面积与调查桥梁数量相近的原则对低烈度区的调查数据进行了补充估计,利用常见的几种经验分布函数拟合了破坏概率直方图,对公路桥梁的易损性矩阵进行了改进,还分析了地震地质灾害的影响。(2)合理地估计了桥址处的PGA数值,基于补充后的调查数据建立了一系列"桥梁-破坏等级-桥址处PGA"样本对,采用最大似然估计法确定了易损性函数中的待定参数,给出了汶川地震公路桥梁的经验易损性曲线,比较分析了拱桥与梁桥之间的易损性差异,并探讨了桥梁规模对易损性的影响。(3)基于SAP2000建立了9种工况下的连续梁桥有限元分析模型,选取36条典型地震动记录为输入,考虑支座和桥墩的非线性行为,进行了桥梁非线性时程分析,在此基础上首先建立了支座和桥墩两种构件的易损性曲线,随后利用一阶界限法合成了整座连续梁桥的易损性曲线,并讨论了不同支承方式对地震易损性的影响,同时验证了桥梁规模对地震易损性的影响规律。(4)通过统计整理近2 000座公路桥梁的详实震害资料,分别得到了拱桥和梁桥的主要震害类型,探讨了它们的发生概率与不同地震烈度的对应关系,分析了关键构件的破坏程度随地震烈度的变化规律。最后,以桥梁破坏等级和典型震害的形式分别提出了评定地震烈度的建议指标,并进行了对比分析和验证。 相似文献
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Vulnerability assessment of reinforced concrete bridge structures in Algiers using scenario earthquakes 总被引:1,自引:1,他引:0
Abderrahmane Kibboua Hakim Bechtoula Youcef Mehani Mounir Naili 《Bulletin of Earthquake Engineering》2014,12(2):807-827
Algeria has an inheritance of more than 11,000 bridges, with approximately 5,000 road bridges of which more than 30 % have a high probability to be exposed to major earthquakes and serious damages in the future. Therefore, it is of great importance to retrofit the existing bridges and assess their seismic vulnerability and set a permanent monitoring survey to follow the change of their dynamic characteristics such as natural frequency and modal damping. The assessment of the seismic vulnerability of existing RC bridges was carried out based on the consistent and complete post earthquake survey after the Boumerdes earthquake. The information on the damaged existing RC bridges was investigated and evaluated by the authors. This paper presents a simple and efficient inspection method for the preliminary evaluation of the seismic vulnerability of existing bridge structures. To assess the seismic damage of 148 existing bridges, two seismic scenarios were carried out using “Khair al Din” and the “Zemmouri” faults that are capable to generate earthquakes with a maximum acceleration of 0.8g. The main findings of this study are summarized in this paper. 相似文献
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陇南公路总段桥梁震害及易损性分析 总被引:1,自引:0,他引:1
陇南公路总段所辖百余座大中小桥,在5.12四川汶川特大地震中遭受了不同程度的损害。本文首先介绍了这些桥梁的震害和现场鉴定情况,然后为验证桥梁易损性理论分析与现场科学考察所得震害等级的一致性,在收集大量所需参数的基础上,采用公路桥梁震害预测经验统计法,对其中154座有详备资料的桥梁进行了易损性分析,并与科考结果进行统计意义上的对比,从较好的一致性中验证了桥梁震害预测结果。最后在公式修正和桥梁加固等方面提出了建议。 相似文献
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为探究山区超高墩三塔大跨斜拉桥在地震作用下各关键构件(桥塔、支座、基础和桥墩)的破坏顺序,以在建的贵州平塘特大桥为工程依托,首先基于OPEENSEES软件建立空间有限元模型,然后基于概率理论建立斜拉桥地震易损性模型,最后以混凝土应变和支座相对位移为易损性指标进行增量动力分析,得到各构件易损性曲线,并基于各构件的易损性曲线对此类桥型的构件破坏顺序进行分析。研究表明:横向地震对该斜拉桥造成的破坏程度要大于纵向地震;在纵向地震作用下桥梁结构最易发生破坏的是中塔支座和边塔基础,在横向地震作用下桥梁结构最易发生破坏的是边塔支座和过渡墩基础。 相似文献
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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
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Effects of structural characterizations on fragility functions of bridges subject to seismic shaking and lateral spreading 总被引:1,自引:0,他引:1
This paper evaluates the seismic vulnerability of different classes of typical bridges in California when subjected to seismic shaking or liquefaction-induced lateral spreading. The detailed structural configurations in terms of superstructure type, connection, continuity at support and foundation type, etc. render different damage resistant capability. Six classes of bridges are established based on their anticipated failure mechanisms under earthquake shaking. The numerical models that are capable of simulating the complex soil-structure interaction effects, nonlinear behavior of columns and connections are developed for each bridge class. The dynamic responses are obtained using nonlinear time history analyses for a suite of 250 earthquake motions with increasing intensity. An equivalent static analysis procedure is also implemented to evaluate the vulnerability of the bridges when subjected to liquefaction-induced lateral spreading. Fragility functions for each bridge class are derived and compared for both seismic shaking (based on nonlinear dynamic analyses) and lateral spreading (based on equivalent static analyses) for different performance states. The study finds that the fragility functions due to either ground shaking or lateral spreading show significant correlation with the structural characterizations, but differences emerge for ground shaking and lateral spreading conditions. Structural properties that will mostly affect the bridges' damage resistant capacity are also identified. 相似文献
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An analytical fragility analysis was conducted in order to characterize the seismic vulnerability of existing southern Illinois wall pier supported highway bridges to potential earthquakes. To perform this fragility analysis, a detailed inventory survey was first taken of the wall pier bridges identified in an earlier random sampling of southern Illinois priority emergency route bridges. From the survey three types of wall pier bridges were identified. Of those identified, hammerhead and regular wall pier supported bridges represented nearly 90% of the population. Incorporating structural variations determined from the random sample survey, nearly 100 three‐dimensional nonlinear finite element models were constructed. Each model was subjected to a randomly assigned synthetic earthquake representative of those that could potentially occur within the region. From these analyses, a series of wall pier supported bridge fragility curves were produced. In addition, a liquefaction fragility analysis was conducted in order to characterize the seismic vulnerability of southern Illinois wall pier supported highway bridge sites to liquefaction in potential earthquakes. To perform this second fragility analysis, wall pier bridges within the southern Illinois random sample that may be susceptible to liquefaction were identified. A soil profile from each of these susceptible bridge sites was then subjected to randomly assigned bedrock motions, and an Arias intensity liquefaction analysis was carried out. From these analyses, a fragility curve for the potentially liquefiable wall pier supported bridge sites was produced. Overall results of this study indicate that southern Illinois wall pier supported bridges are moderately vulnerable to structural damage in a 2% probability of exceedance in 50 year earthquake, and in some cases they could also be highly vulnerable to on‐site liquefaction events. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献