【摘要】：近些年來，隨著我國在基礎設施建設方面的快速發展，所修建的橋梁結構的數量大幅增加，橋梁結構形式也因為美觀上的要求多種多樣，而懸索橋這種古老的橋型，卻始終煥發著旺盛的生命力。 地震作用下，橋梁結構經常遭到破壞，給人們的通行以及救災造成很大的不便，所以對結構進行地震反應分析，并根據分析結果采取抗震或者減隔震措施顯得非常必要。 本文以劉家峽懸索橋為工程背景，利用有限元分析軟件MIDAS/CIVIL建立全橋模型，分析其動力特性，計算其地震反應，并根據地震反應結果采取減震措施并對減震效果進行評價和對比。具體主要工作內容如下： （1）查閱文獻，對在地震荷載作用下橋梁結構遭到的破壞形式進行分析，發現在結構的破壞過程中，支座往往最先遭到破壞，作為連接橋梁上、下部結構的重要部分，它的破壞會造成上部結構的滑移、脫落以及傾覆，上部結構的脫落和傾覆又會造成下部結構的破壞。 （2）利用有限元分析軟件MIDAS/CIVIL建立了劉家峽懸索橋的動力分析有限元模型，在建立基礎模型的過程中，考慮到樁基與土的相互作用，本文利用彈性地基梁法，模擬樁—土效應。建立整體模型后，對其進行自振特性分析，為后面的地震反應分析做準備。 （3）根據橋址區地質條件以及抗震要求，確定要輸入到橋梁結構中的反應譜函數，然后對模型進行反應譜分析，分析過程中考慮結構在不同輸入方向下的地震反應。 （4）根據場地周期以及地質條件等，確定三組不同的經典地震波作為輸入到結構中的地震荷載，對這三組波進行調整，使其符合擬建場地的要求，然后求解結構在該三組波作用下的地震反應，并對其進行分析。 （5）根據地震反應結果，本文決定給結構添加液體粘滯阻尼器作為減震措施。根據文獻和資料，確定適合結構的粘滯阻尼器，，對其阻尼系數、阻尼指數等技術參數進行分析。并將這些參數輸入到橋梁結構的有限元模型中。 （6）給結構添加粘滯阻尼器后，對其進行地震反應分析，得出結構在添加減震措施后，結構的內力值和位移值，并將該值與未添加減震措施時的結構地震反應值進行對比。 （7）經對比可知，結構在添加減震措施后，結構在塔頂處以及梁端支座處的順橋向和橫橋向的地震位移幅值明顯降低，塔底的內力值也明顯減小，說明該減震措施效果較好。
[Abstract]:In recent years, with the rapid development of infrastructure construction in our country, the number of bridge structures built has increased significantly, and the form of bridge structure is also varied because of aesthetic requirements, and suspension bridge is an ancient bridge type. But always radiant with exuberant vitality. Under earthquake action, bridge structure is often damaged, causing great inconvenience to people's passage and disaster relief, so it is very necessary to analyze the seismic response of the structure and to take seismic or seismic isolation measures according to the analysis results. Taking the Liujiaxia suspension bridge as the engineering background, the finite element analysis software MIDAS/CIVIL is used to establish the full bridge model, to analyze its dynamic characteristics, to calculate its seismic response, and to take measures to reduce the earthquake according to the results of the seismic response, and to evaluate and compare the seismic absorption effect. The main contents of the work are as follows: (1) referring to the literature and analyzing the damage form of bridge structure under earthquake load, it is found that in the process of structural damage, the support is often first destroyed. As an important part of the connecting bridge and the substructure, its failure will cause the superstructure to slip, fall off and overturn. The shedding and overturning of the superstructure will cause damage to the substructure. (2) the finite element model of the Liujiaxia suspension bridge is established by using the finite element analysis software MIDAS/CIVIL. Considering the interaction between pile foundation and soil, this paper simulates the pile-soil effect by means of elastic foundation beam method. After the whole model is established, the natural vibration characteristics of the model are analyzed to prepare for the subsequent seismic response analysis. (3) according to the geological conditions of the bridge site and the seismic requirements, the response spectrum function to be input into the bridge structure is determined. Then the response spectrum of the model is analyzed, and the seismic response of the structure in different input directions is considered. (4) according to the site period and geological conditions, Three sets of different classical seismic waves are determined as the seismic load input to the structure, and the three sets of waves are adjusted to meet the requirements of the proposed site, and then the seismic response of the structure under the action of the three sets of waves is solved. (5) according to the results of seismic response, this paper decides to add liquid viscous damper to the structure as a shock absorption measure. According to the literature and data, the viscous damper suitable for the structure is determined, and the technical parameters such as damping coefficient and damping index are analyzed. These parameters are input into the finite element model of bridge structure. (6) after adding viscous damper to the structure, the seismic response of the structure is analyzed, and the internal force and displacement value of the structure after adding the damping measures are obtained. This value is compared with the seismic response value of the structure without adding the damping measures. (7) by comparison, the structure after adding the damping measures, The amplitude of seismic displacement and the internal force at the bottom of the tower are obviously reduced at the top of the tower and at the support of the beam end, which indicates that the effect of the measure is good.
【學位授予單位】：蘭州交通大學
【學位級別】：碩士
【學位授予年份】：2014
【分類號】：U448.25

【參考文獻】

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