大跨度人行悬索桥颤振稳定性与人致振动响应研究

发布时间：2018-05-19 12:40

本文选题：大跨度悬索桥 + 风致振动　；参考：《湖南大学》2015年硕士论文

【摘要】：随着人行悬索桥跨径的不断增大,结构质量更轻、刚度更小、阻尼更低,结构变得更加轻柔,对风荷载、人群荷载等的敏感性越来越显著,极易产生较大的振动和变形,影响结构的正常使用甚至引发灾难。因此,需要对大跨人行悬索桥进行风致振动,尤其是颤振性能的研究,以及人致振动的研究,对可能出现的过度振动应采取措施进行控制。为了研究大跨度人行悬索桥的颤振稳定性及人致振动性能,以优化断面后加装风嘴的张家界人行悬索桥为工程背景,该桥主跨430m,加劲梁长375m,主梁高跨比1/625、宽跨比1/62.5,空间主缆垂跨比1/14,结构特征非常突出,比旧塔科马桥更加轻柔。通过节段模型强迫振动试验和全桥气弹模型风洞试验,对该桥开展了颤振稳定性的研究。分析了该人行桥的人致振动性能,利用TMD进行了减振方案的研究。论文的主要研究内容和取得的成果如下:(1)介绍了悬索桥的发展历史以及人行悬索桥在我国的应用状况,简述了桥梁的风致振动与人致振动的类型及危害,概括了用于桥梁振动控制的方法。提出了本文主要研究内容。(2)分析了张家界人行悬索桥的动力特性,阐述了气动弹性模型制作应满足的相似要求,并基于相似性要求设计了变刚度加劲梁空间索面悬索桥的气动弹性模型,且动力特性测试结果满足要求。分析了模型主梁刚度的影响因素,提出了一种用于模型吊杆铁丝预处理的方法。(3)为研究风嘴的优化效果,开展节段模型的强迫振动风洞试验并识别了8个颤振导数,利用全模态三维颤振分析方法进行桥梁的颤振分析。颤振分析与全桥气弹模型风洞试验的结果表明,加装风嘴能显著提高气动外形钝化的开口主梁的颤振临界风速;张家界人行悬索桥的最终设计方案具有较高的颤振临界风速,完全满足颤振稳定性要求。(4)基于人行桥振动特性及舒适度评价理论,分析了不同人行荷载工况下的振动响应,并利用TMD系统进行了振动控制研究,初步计算了电涡流TMD的参数。研究表明,当桥上同步人数超过200时,加速度响应超出很舒适等级限值,当超过400人时,可能出现不舒适现象;TMD系统具有良好的减振效果,且质量比(2%)越大,减振效果越明显。
[Abstract]:With the increasing span of footbridge, the mass of the structure is lighter, the stiffness is smaller, the damping is lower, the structure becomes softer, the sensitivity to wind load and crowd load is more and more obvious, and it is easy to produce larger vibration and deformation. Affect the normal use of the structure and even lead to disaster. Therefore, it is necessary to study the wind-induced vibration, especially the flutter performance of the long-span footbridge, as well as the study of the human-induced vibration. Measures should be taken to control the possible excessive vibration. In order to study the flutter stability and man-made vibration performance of a long-span footbridge, the Zhangjiajie suspension bridge with wind nozzles is used as the engineering background. The main span of the bridge is 430 m, the stiffening beam length is 375 m, the ratio of height to span of main beam is 1 / 625, the ratio of width to span is 1 / 62.5, the vertical span ratio of space main cable is 1 / 14, and the structural features are very prominent and softer than the old Tacoma bridge. The flutter stability of the bridge is studied by means of the forced vibration test of the segmental model and the wind tunnel test of the Aeroelastic model of the whole bridge. The vibration performance of the footbridge is analyzed, and the vibration reduction scheme is studied by TMD. The main contents and achievements of this paper are as follows: (1) the development history of suspension bridge and its application in our country are introduced, and the types and harm of wind-induced vibration and human-induced vibration of bridge are briefly described. The method of bridge vibration control is summarized. The dynamic characteristics of the suspension bridge of Zhangjiajie people's Bank are analyzed, and the similar requirements of making the Aeroelastic model are expounded. The Aeroelastic model of the space cable surface suspension bridge with variable stiffness and stiffened beam is designed based on the similarity requirement, and the test results of the dynamic characteristics meet the requirements. This paper analyzes the factors affecting the stiffness of the main beam of the model, and puts forward a method for pretreatment of the model suspender wire. In order to study the optimization effect of the wind nozzles, the forced vibration wind tunnel test of the segmental model is carried out and eight flutter derivatives are identified. The full modal three-dimensional flutter analysis method is used for bridge flutter analysis. The results of flutter analysis and wind tunnel test of full bridge Aeroelastic model show that the flutter critical wind speed of the passivated open main girder with aerodynamic shape can be significantly increased by adding the air nozzle, and the final design scheme of Zhangjiajie pedestrian suspension bridge has higher critical flutter velocity. Based on the theory of vibration characteristics and comfort evaluation of footbridge, the vibration response under different conditions of walking load is analyzed, and the vibration control is studied by using TMD system, and the parameters of eddy current TMD are preliminarily calculated. The results show that when the synchronous number on the bridge exceeds 200, the acceleration response exceeds the limit of very comfortable level, and when the number of people exceeds 400, the TMD system may have a good damping effect, and the bigger the mass is, the more obvious the vibration reduction effect is.
【学位授予单位】：湖南大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U441.3;U448.25

【相似文献】