| 基于车桥耦合随机振动分析的钢桥疲劳可靠度评估 |
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| 引用本文： | 李慧乐, 夏禾. 基于车桥耦合随机振动分析的钢桥疲劳可靠度评估[J]. 工程力学, 2017, 34(2): 69-77. DOI: 10.6052/j.issn.1000-4750.2015.04.0334 |
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| 作者姓名： | 李慧乐 夏禾 |
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| 作者单位： | 1.东南大学土木工程学院, 江苏, 南京 210096;;2.北京交通大学土木建筑工程学院, 北京 100044 |
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| 基金项目： | 国家重点基础研究发展计划973项目（2013CB036203）；国家科技支撑计划项目（2014BAK11B04） |
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| 摘 要： | 发展了一种基于车桥耦合系统随机振动分析的铁路钢桥疲劳可靠度评估方法，建立车桥耦合系统模型，选取车速和轨道不平顺作为基本随机变量进行随机振动分析，以此确定桥梁构件等效疲劳应力幅及其循环次数的概率模型。在此基础上，建立基于S-N曲线法的疲劳极限状态函数并进行疲劳可靠度分析。以一座铁路下承式钢桁梁桥为例进行了疲劳可靠度评估，并讨论了车速及轨道平顺性对构件疲劳可靠性的影响。结果表明：该文方法可有效用于铁路钢桥疲劳可靠度评估；受车速及轨道不平顺随机性的影响，列车引起的桥梁构件等效疲劳应力幅及其循环次数均具有一定的不确定性，应视为随机变量，二者可采用对数正态分布表示；车速和轨道不平顺可显著影响桥梁构件的疲劳可靠性，疲劳关键构件的可靠度指标随着轨道平顺性增强而提高。
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| 关 键 词： | 疲劳 可靠度评估 随机振动 车桥耦合系统 钢桥 |
| 收稿时间： | 2015-04-22 |
| 修稿时间： | 2015-12-28 |
FATIGUE RELIABILITY EVALUATION OF STEEL BRIDGES BASED ON COUPLING RANDOM VIBRATION ANALYSIS OF TRAIN AND BRIDGE |
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| LI Hui-le, XIA He. FATIGUE RELIABILITY EVALUATION OF STEEL BRIDGES BASED ON COUPLING RANDOM VIBRATION ANALYSIS OF TRAIN AND BRIDGE[J]. Engineering Mechanics, 2017, 34(2): 69-77. DOI: 10.6052/j.issn.1000-4750.2015.04.0334 |
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| Authors: | LI Hui-le XIA He |
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| Affiliation: | 1.School of Civil Engineering, Southeast University, Nanjing 210096, China;;2.School of Civil Engineering, Beijing Jiaotong University, Beijing 100044, China |
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| Abstract: | Based on the random vibration analysis of a coupled train-bridge system, an approach for fatigue reliability assessment of railway steel bridges is presented. A coupled train-bridge system model is established. Train speed and track irregularities are selected as the basic random variables to perform the random vibration analysis and to identify probabilistic models of the equivalent fatigue stress range and its cyclic number of bridge components. On this basis, a fatigue limit state function is constructed to conduct fatigue reliability analysis by using the S-N curve approach. As an illustrative example, the fatigue reliability assessment is performed for a through steel truss bridge on railroad. The effects of train speed and track irregularities on the fatigue reliability of components are discussed. The results show that the presented approach can be utilized to effectively assess the fatigue reliability of railway steel bridges. Because of the randomness in train speed and track irregularities, both the train-induced equivalent fatigue stress range and its number of cycles of bridge components are indeterminate, which should be considered as random variables and can be represented by a lognormal distribution. Train speed and track irregularities can significantly affect the fatigue reliability of bridge members. The reliability indexes of fatigue-critical members increase with the enhancement in track smoothness. |
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| Keywords: | fatigue reliability assessment random vibration coupled train-bridge system steel bridge |
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