發(fā)布時間：2018-05-19 12:40

  本文選題：大跨度懸索橋 + 風致振動　； 參考：《湖南大學》2015年碩士論文

【摘要】：隨著人行懸索橋跨徑的不斷增大,結構質量更輕、剛度更小、阻尼更低,結構變得更加輕柔,對風荷載、人群荷載等的敏感性越來越顯著,極易產生較大的振動和變形,影響結構的正常使用甚至引發(fā)災難。因此,需要對大跨人行懸索橋進行風致振動,尤其是顫振性能的研究,以及人致振動的研究,對可能出現(xiàn)的過度振動應采取措施進行控制。為了研究大跨度人行懸索橋的顫振穩(wěn)定性及人致振動性能,以優(yōu)化斷面后加裝風嘴的張家界人行懸索橋為工程背景,該橋主跨430m,加勁梁長375m,主梁高跨比1/625、寬跨比1/62.5,空間主纜垂跨比1/14,結構特征非常突出,比舊塔科馬橋更加輕柔。通過節(jié)段模型強迫振動試驗和全橋氣彈模型風洞試驗,對該橋開展了顫振穩(wěn)定性的研究。分析了該人行橋的人致振動性能,利用TMD進行了減振方案的研究。論文的主要研究內容和取得的成果如下:(1)介紹了懸索橋的發(fā)展歷史以及人行懸索橋在我國的應用狀況,簡述了橋梁的風致振動與人致振動的類型及危害,概括了用于橋梁振動控制的方法。提出了本文主要研究內容。(2)分析了張家界人行懸索橋的動力特性,闡述了氣動彈性模型制作應滿足的相似要求,并基于相似性要求設計了變剛度加勁梁空間索面懸索橋的氣動彈性模型,且動力特性測試結果滿足要求。分析了模型主梁剛度的影響因素,提出了一種用于模型吊桿鐵絲預處理的方法。(3)為研究風嘴的優(yōu)化效果,開展節(jié)段模型的強迫振動風洞試驗并識別了8個顫振導數(shù),利用全模態(tài)三維顫振分析方法進行橋梁的顫振分析。顫振分析與全橋氣彈模型風洞試驗的結果表明,加裝風嘴能顯著提高氣動外形鈍化的開口主梁的顫振臨界風速;張家界人行懸索橋的最終設計方案具有較高的顫振臨界風速,完全滿足顫振穩(wěn)定性要求。(4)基于人行橋振動特性及舒適度評價理論,分析了不同人行荷載工況下的振動響應,并利用TMD系統(tǒng)進行了振動控制研究,初步計算了電渦流TMD的參數(shù)。研究表明,當橋上同步人數(shù)超過200時,加速度響應超出很舒適等級限值,當超過400人時,可能出現(xiàn)不舒適現(xiàn)象;TMD系統(tǒng)具有良好的減振效果,且質量比(2%)越大,減振效果越明顯。
[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.
【學位授予單位】：湖南大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：U441.3;U448.25

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本文編號：1910136