【作者】 陈勉；

【导师】 马存明；

【作者基本信息】 西南交通大学 ， 建筑与土木工程， 2013， 硕士

【摘要】 当今斜拉桥正朝着超大跨度、极度柔性方向迈进,大跨度桥梁的风致振动问题已成为在桥梁设计中必须考虑的关键问题,特别是施工期的最大悬臂状态的抗风安全。抖振是在紊流作用下的随机性强迫振动,由于其发生的频率较高,已成为桥梁抗风设计中日益重要的课题。现有的大跨桥梁的抖振响应研究成果大部分是针对单箱梁的,对于分离式钢箱梁的气动参数和抖振响应特征缺乏系统的研究,本文以嘉绍桥为工程背景,对分体式钢箱梁斜拉桥的抖振响应进行了系统的研究。首先,叙述了现代斜拉桥的发展历程和各时期的代表作,以及我国关于斜拉桥的发展情况,并阐述了斜拉桥抗风研究的必然性和其风振响应特点；其次,介绍通过ansys有限元软件对桥梁结构进行动力特性分析的方法和模型模拟的单元选取,对分体式钢箱梁斜拉桥的结构动力特性进行了分析；然后,回顾了抖振分析的常用方法,介绍了频域分析中的三个代表性理论：Davenport随机抖振理论、Scanlan颤抖振理论、Y.K.Lin理论,并叙述了频域和时域法的分析过程。并重点介绍了利用随机振动理论,通过全桥气弹模型试验获取抖振位移响应和关键断面抖振力的方法和过程。最后,以嘉绍大桥这种分体式钢箱梁独塔柱多跨斜拉桥为工程背景,通过节段模型风洞试验,测得分体式钢箱梁的气动参数,算出其静风内力,然后利用全桥气动弹性模型试验,根据试验得出的位移响应,推算出成桥和施工阶段的内力响应,特别是成桥和施工阶段的支座反力,为类似桥梁抗风支座的设计提供了依据。更多还原

【Abstract】 The development of modern super-large and flexible bridges has resulted in the wind-induced vibrations, which have become some important problems of great concern during the design of long-span bridges. Especially, the safety of bridges in the double-cantilever stage with wind load becomes very significant. Buffeting is defined as the unsteady loading of a structure by velocity fluctuations in the oncoming flow. Because it occurs very frequently, buffeting analysis has become an important part of wind-induced vibration research. Most existing studies on buffeting response of long-span bridges are mostly about to the single-box girder, the aerodynamic parameters and the buffeting response of multi-span bridges are lacking in systematic studies. Take the Jia-shao Bridge as engineering background, this paper have studied on the buffeting response of multi-span separated steel box girder cable-stayed bridges.Firstly, this paper introduces the development of modern cable-stayed bridges and masterpieces at different times in the world, especially in our country, and then it elaborates the necessity of wind resistance and characteristics of wind-induced vibration.Secondly, the dynamic characteristic of multi-span separated steel box girder cable-stayed bridges was analyzed. After introducing the method of dynamic characteristics analysis based on finite element method software (ANSYS), and element choice of modal imitation.Thirdly, retrospect common methods of buffeting analysis, and introduces three typical theories of frequency domain analysis, such as Davenport Random buffeting theory, Scanlan flutter-buffeting theory, Y.K. Lin theory. This paper states the analysis process of frequency domain and time domain, and focuses on using the theory of random vibration. It obtains a process and a method that can analyze the buffeting displacement response and the buffeting force of key sections through tests on models of the full bridge.Lastly, take the Jia-shao Bridge, which is multi-span separated steel box girder cable-stayed bridge, as engineering background, via tests of section models, this paper measures the aerodynamic parameters of separated steel box girder and then gets the static wind forces. Then it tests of the full bridges. By analyzing the experimental data which is about displacement response, this paper gets the forces of bridges with wind load in the completed stage and the construction stage, especially gets support reaction. It provides the evidence from experience for the design of supports with wind load of similar bridges.更多还原