动力特性分析在桥梁检测评估中的应用

文章以某大桥的动力特性测试为例,对桥梁的脉动信号及动力特性进行了测试和分析处理,并结合有限元分析结果,表明结构动力特性检测在具体的桥梁结构动力检测评定中的有效性,对结构振动控制和整体性能评估都具有实用意义。     

斜拉桥模态测试与分析

桥梁结构的动力特性是结构抗震、抗风以及进行在线健康监测的基础。使用大型结构有限元分析程序建立杭州市文晖大桥三维有限单元模型,对大桥进行动力特性理论分析。计算结果与实桥脉动测试法(也称环境随机振动法)的测试结果相当吻合,验证了模型以及脉动测试法的有效性,也为大桥的进一步研究提供了依据。     

某桥梁结构动力特性数据处理方法

桥梁结构动力特性检测是桥梁健康诊断与安全性评估的一项检测内容,通过某大桥的动力特性测试实例,运用MATLAB语言编程对动力特性测试数据进行数据分析处理,分析结果表明这种处理方法是可行的,为以后桥梁结构动力特性测试数据的处理提供了依据。     

中承式钢管混凝土肋拱桥的动力特性研究

本文以福建省石潭溪大桥为研究对象，建立空间结构计算模型，利用有限元法分析了中承式钢管混凝土肋拱桥的动力特性及主要结构参数对动力特性的影响。     

基于动态特性灵敏度分析的斜拉桥有限元模型修正

采用基于动态特性灵敏度分析理论对润扬大桥斜拉桥的有限元模型进行修正,建立了最终的全桥结构有限元模型,较为准确的反映了桥梁的实际结构动力特性。     

某石拱桥检测鉴定技术评析

通过某大桥检测工程实例,对石拱桥的静力性能参数和结构动力相应特性进行了对比分析,进而对旧式石拱桥的承载能力进行评定。     

基于健康监测系统斜拉桥有限元模型修正的实现

目前结构健康监测成为解决工程结构安全性和耐久性的前沿性课题。以深圳湾公路大桥斜拉桥为工程背景,采用健康监测系统提供的数据获得斜拉桥的拉索索力和模态参数。在分析设计变量对模态参数变化的灵敏度特性的基础上对建立的有限元模型进行修正,比较快速有效地得到了能够较好的反映大桥动力特性的基准有限元模型,为大桥的健康监测和损失预警研究提供了基础。     

土-桩-结构相互作用对大跨悬索桥动力特性的影响研究

本文以国内第一大跨桥梁———润扬长江公路大桥南汊悬索桥为研究对象,基于大型有限元分析软件ANSYS建立了该桥的三维有限元模型,其中采用质量-弹簧体系模拟了土-桩-结构的相互作用。以此为基础对润扬悬索桥的自振特性进行了分析,重点研究了土-桩-结构相互作用因素对大跨悬索桥动力特性的影响,与现场动力测试结果的良好吻合表明了有限元分析结果的可靠性。研究结果为大桥的损伤预警和状态评估奠定了研究基础。     

大跨度钢-混组合梁斜拉桥悬臂施工及成桥阶段模态研究

大跨度钢-混组合梁斜拉桥结构施工和成桥阶段的模态参数(振动频率、振型及阻尼比)是大桥动力学性能的决定因素之一,也是结构总体状态的一种表征。斜拉桥结构的结构体系问题、抗风性能、抗震性能均与大桥结构的动力特性密切相关。采用MIDAS/Civil结构分析软件建立了齐河黄河大桥钢箱梁斜拉桥的三维有限元模型,分析了大桥在施工和成桥阶段的振动特性,并与现场跟踪模态测试结果进行了比较,总结并完善斜拉桥悬臂施工中结构关键节点的振动分析,分析索塔施工和主梁悬拼过程中结构模态参数,剖析了斜拉桥在悬臂施工过程和成桥后结构自振特性的变化规律。     

辅助墩对斜拉桥动力性能的影响

对某斜拉桥的动力特性及纵横两个方向的地震反应时程进行分析,在此基础上探讨设置辅助墩对上部结构动力特性及地震反应的影响,认为设置辅助墩并非在任何情况下都有利于减低上部结构的地震反应,同时对大桥的抗风问题也作了讨论。     

Advanced dynamic finite element analysis of a skew steel railway bridge

The aim of this paper is to present advanced modelling techniques for dynamic analysis of steel railway bridges. Finite element analyses of a case study skew bridge are carried out and the results are compared with available field measurements. Initially, eigenvalue analyses of different models are carried out in order to obtain the fundamental mode shapes and bridge frequencies and to assess the capability of each model to capture the dynamic behaviour of the bridge. Single-span, three-span and full bridge models are investigated with different elements such as shell, beam and combinations of these. A very good agreement between the fundamental dynamic properties of the bridge and empirical results is found. Following the eigenvalue analyses, time history dynamic analyses are carried out using the full bridge model. The analyses are carried out for different train speeds and the strain histories are compared with available field measurements. In terms of fatigue assessment, the mean stress range values obtained from the strain histories at selected locations on the bridge members are also compared to each other. The results show that a full bridge model using a combination of beam and shell elements is a reasonably accurate and computationally efficient way of capturing the dynamic behaviour of a bridge and estimating the mean stress range for fatigue damage calculations.     

Modal analysis of suspension bridge deck units in erection stage

A long suspension bridge located in a typhoon region may be exposed to a high risk of wind-induced large vibrations during the construction stage because of its long construction period. The dynamic properties of the bridge in different construction stages therefore have to be well understood in bridge design, so that a proper wind tunnel test or further dynamic response analysis can be performed. To this end, this paper presents a detailed finite element modeling and modal analysis of the Tsing Ma long suspension bridge when the first few deck units are erected at the bridge midspan. The three-dimensional finite element model includes not only the deck units but also the main cables to which the deck units are suspended through hangers, the bridge towers, and the side span cables. The results from the numerical analysis show a clear picture of how dynamic properties are transformed from the tower-cable system to the tower-cable-deck unit system. The results indicate that wind-induced vibration of a cable suspension bridge during the construction stage may be more critical than that of the completed bridge. The predicted natural frequencies and mode shapes of the tower-cable-deck unit system are also compared with the measured results, and the comparison is satisfactory.     

桥梁防撞系统动力特性分析

研究了桥墩防撞系统的动力特性。首先阐述了空间杆系结构有限元分析的基本原理,然后采用大型商业化软件ANSYS建立了桥墩防撞系统的三维有限元模型。在此基础上,简要阐述了结构动力特性分析的基本原理,研究了桥墩防撞系统的动力特性并分析了结构频率和振型的特点。     

斜铁路钢桥的高等动力有限元分析

介绍斜铁路钢桥动态分析的模型。给出一个有限元分析的案例及其与实际测量结果的对比。首先,通过不同模型的特征值分析,得到基础模型选型和桥梁频率,以及评估每个模型分析桥梁动态性能的能力。通过壳单元、梁单元以及组合单元对单跨、三跨和全比例桥梁建模。结果显示,桥梁基本动态特征数值分析结果与试验结果吻合。全比例桥梁模型用于分析特征值和动力时程分析。对不同列车时速和应变记录的分析与实际测量进行比较。疲劳评估通过选取桥梁某一位置的平均应力值也进行了比较研究。结果表明,采用梁单元和壳单元的组合单元的全比例尺模型,可以高效准确地预测桥梁的动力性能和疲劳破坏的平均应力值的范围。     

整体式桥台桥梁的动力特性及参数研究

提出一个模拟土体-结构非线性相互作用的模型,用于整体式桥台桥梁的动力特性分析。在此基础上建立一座整体式桥台桥梁的有限元模型,分析了土体-结构非线性相互作用和整体式桥台桥梁动力特性之间的关系,并讨论了主要参数对整体式桥台桥梁动力特性的影响。研究结果有助于认识整体式桥台桥梁的动力性能。     

广州虎门悬索桥的模态分析

通过利用GPS技术对广州虎门悬索桥进行连续实时监测 ,现场测试了大桥的固有模态。介绍了所用的测试方法以及大桥固有模态的识别过程 ,并建立了三维空间有限元进行动力分析。通过实验和理论的相互比较 ,得出大桥的自振动力特性 ,同时也验证了大桥的抗震、抗风特征参数 ,为大桥的安全在线监测提供了依据     

公路装配式简支梁桥空间受力特性分析

基于三维实体单元建立朗江大桥其中1孔的三维有限元模型,计算该孔的动力特性,并采用DASP动力测试系统对其中6跨进行了动载实验,比较分析其动力特性,同时对其中1跨进行了静力荷载实验,深入探讨了各片梁的空间受力行为,以达到提高整体承载力的目的。     

Monitoring the dynamic characteristics of an urban bridge before,during and after widening

The dynamic characteristics of a multi-span pre-stressed concrete urban bridge before, during and after widening operations have been studied. The widening operations have been carried out by adding two new bridges on the either sides of the old bridge. The decks of the new bridges have been structurally separated from the old one by two longitudinal joints on the either side of the old bridge. The dynamic characteristics have been extracted from operational modal tests in three phases during different stages of the widening operations. The dynamic interaction between the new parts and the old part of the bridge has also been investigated. The results show that after the completion of the widening works, and when the whole bridge was placed in service condition, this interaction affects the natural frequencies of almost all the vibration modes of the bridge. It was also found that the longitudinal joints were unable to effectively isolate the new parts from the old part. Finally, in order to achieve a consistent behaviour in the first bending mode of the new and old bridges, a geometrical index has been introduced. This index includes both the effects of stiffness and mass properties of the bridge deck. In widening projects, where the span lengths, material properties and support conditions of the two bridges are taken the same, adopting equal geometrical indices leads to almost equal values of the natural frequencies and similar mode shapes in the first bending mode. The proposed index can be used in the initial design stage for such projects.     

既有钢管混凝土拱桥桥动力测试和有限元分析

桥梁结构的动力特性(振型、频率和阻尼)是桥梁承载能力评定的重要参数,同时也是识别桥梁结构工作性能和桥梁抗震分析的重要参数。     

钢管混凝土拱桥有限元模拟及动力分析

阐述了利用有限元分析软件ANSYS建立钢管混凝土拱桥的计算模型的方法,并利用有限元模型对桥梁进行了理论模态分析,计算出自振频率、振型等动力参数,对其振型特征进行了分析和研究,以期全面的评价桥梁结构的动力性能。