本文選題：車橋耦合振動 + 動力沖擊系數�。� 參考：《湖南大學》2015年碩士論文

【摘要】：中小跨徑梁橋構造簡單、受力明確,具有設計和施工高度標準化的特點,是世界上應用最為廣泛的橋型。截至2010年底,我國公路橋梁已經超過65萬座,中小跨徑梁橋占據了其中絕大部分。然而近幾十年來公路運輸需求迅速擴大,車輛荷載、數量和車速均不斷提高,橋梁失效事件時有發(fā)生,使得明確中小跨徑梁橋在移動車輛荷載作用下的動力荷載效應、獲得準確的橋梁動力沖擊系數(IM)以用于評估既有橋梁承載力和合理指導新橋設計,成為橋梁領域亟待解決的重要問題。世界各國(包括我國)學者已經指出橋梁設計規(guī)范中使用的沖擊系數可能低估了橋梁的實際動力響應。且目前關于橋梁支承方式、橋梁截面類型、橋梁受力構件材料、車輛荷載等級等因素對IM的影響的研究不夠深入。規(guī)范計算IM時,對這些重要影響因素也并未加以考慮。本文建立了基于車橋耦合振動理論的IM研究方法,對中小跨徑梁橋在車輛荷載作用下的IM進行了研究,深入探討了IM受截面形式、支承方式、路面等級、橋梁跨徑、行車速度等因素影響的規(guī)律,獲得了一些有意義的結論。這些成果可做為規(guī)范的補充為橋梁研究人員和工程師所參考。主要內容如下:(1)推導和建立了車輛、橋梁的有限元模型和車橋耦合振動動力學方程,結合模態(tài)疊加法,推導了逐步迭代求解的數值算法,給出了編制電算程序的流程。(2)通過數值模擬方法計算了多種不同類型中小跨徑梁橋在復雜行駛工況下的IM,用計算結果對中美橋梁設計規(guī)范進行了檢驗,指出了我國89規(guī)范、04規(guī)范設計值可能低估了車輛行駛時橋梁的實際IM。(3)計算了常見不同截面類型梁橋的IM。對路面平整度、車輛類型、行車速度等重要因素進行了參數分析,指出不同截面類型橋梁的IM具有較大的離散性,其差異應引起工程人員的注意。(4)建立了混凝土簡支橋梁、連續(xù)梁橋及鋼主梁—混凝土面板橋梁模型,分別探討了連續(xù)梁橋IM和簡支梁橋IM、彎矩IM和剪力IM的差異。發(fā)現現行規(guī)范對橋梁支承方式、橋梁上部結構材料引起的IM差異的考慮不足,將現行規(guī)范應用于連續(xù)梁橋和組合梁橋可能并不十分合理。
[Abstract]:Small and medium span girder bridge is the most widely used bridge type in the world because of its simple structure, clear force and high standardization in design and construction. Up to the end of 2010, there are more than 650000 highway bridges in China, most of which are small and medium span girder bridges. However, in recent decades, the demand for highway transportation has expanded rapidly, the vehicle load, quantity and speed have been increasing continuously, and the bridge failure events have occurred from time to time, which makes clear the dynamic load effect of small and medium-sized span beam bridge under moving vehicle load. Obtaining accurate dynamic impact coefficient (IMC) of bridges to evaluate the bearing capacity of existing bridges and reasonably guide the design of new bridges has become an important problem to be solved urgently in the field of bridges. Scholars from all over the world (including China) have pointed out that the impact coefficient used in the bridge design code may underestimate the actual dynamic response of the bridge. At present, the research on the influence of bridge supporting mode, bridge section type, bridge bearing material, vehicle load grade and other factors on IM is not deep enough. These important factors are not taken into account when calculating IM. In this paper, an IM research method based on vehicle-bridge coupling vibration theory is established, and the IM of medium and small span beam bridge under vehicle load is studied, and the form of section, supporting mode, pavement grade, span of bridge are deeply discussed. Some meaningful conclusions are obtained on the influence of driving speed and other factors. These results can be used as a reference for bridge researchers and engineers. The main contents are as follows: (1) the finite element model of vehicle and bridge and the dynamic equation of vehicle-bridge coupling vibration are derived and established. Combined with the modal superposition method, the numerical algorithm of step by step iterative solution is derived. The flow chart of compiling computer program is given. (2) through numerical simulation method, the IMMOs of many different types of small and medium span girder bridges under complex driving conditions are calculated, and the design codes of bridges in China and America are tested with the results of calculation. It is pointed out that the design value of the code YI04 of 89 code of our country may underestimate the actual IM.3 of the bridge when the vehicle is running) and calculate the IMs of the common beam bridges of different cross-section types. This paper analyzes the important factors such as pavement smoothness, vehicle type, driving speed and so on, and points out that the IM of different cross-section bridges has greater discreteness, the difference of which should attract the attention of engineers. The model of continuous beam bridge and steel main beam-concrete slab bridge is discussed, and the difference of IM, moment IM and shear IM of continuous beam bridge and simply supported beam bridge is discussed respectively. It is found that the current code does not consider the bridge support mode and the IM difference caused by the bridge superstructure material, and it may not be very reasonable to apply the current code to continuous beam bridges and composite beam bridges.
【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

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