本文關(guān)鍵詞：變截面鋼—混凝土組合連續(xù)梁橋受力特性分析　出處：《蘭州交通大學》2014年碩士論文　論文類型：學位論文

  更多相關(guān)文章： 鋼-混凝土連續(xù)組合梁 徐變 裂縫寬度 施工方法

【摘要】：近年來，鋼-混凝土組合結(jié)構(gòu)在工程中得到廣泛應用，但人們對組合結(jié)構(gòu)的一些問題的研究還不夠深入，比如收縮徐變問題。收縮徐變使組合結(jié)構(gòu)產(chǎn)生內(nèi)力及應力重分布，影響結(jié)構(gòu)的承載能力；對于鋼-混凝土組合連續(xù)梁橋，支座區(qū)域較大的負彎矩容易使橋面板拉應力過大產(chǎn)生開裂的現(xiàn)象等。本文以贊比亞奇阿瓦40m+60m+40m鋼-混凝土組合連續(xù)梁橋為工程背景，借助Midas/Civil有限元分析程序?qū)υ摌蜻M行分析，針對徐變對組合梁產(chǎn)生的內(nèi)力及應力重分布，溫度作用效應，負彎矩下混凝土橋面板裂縫寬度，以及減小負彎矩區(qū)段橋面板拉應力的施工方法這幾個方面進行分析。具體工作如下： 1、分析橋面板混凝土徐變對組合梁的內(nèi)力及應力重分布作用，分析了加載齡期和相對濕度對徐變效應的影響，混凝土收縮對徐變效應的影響。溫度作用對組合梁橋內(nèi)力的影響，得出溫度應力主要由混凝土和鋼梁之間的溫差產(chǎn)生。同時分析了溫差作用下，當橋面板厚度及彈性模量比變化時，組合梁應力變化規(guī)律。 2、對負彎矩作用下橋面板的承載力及裂縫寬度進行了計算，結(jié)果表明均滿足規(guī)范要求。計算了不同荷載工況下橋面板裂縫寬度，得出影響負彎矩下橋面板裂縫寬度的最不利荷載。分析了相對濕度，，組合梁的截面高度比以及橋面板的配筋率三種因素對橋面板裂縫寬度的影響。 3、針對連續(xù)組合梁橋負彎矩區(qū)橋面板承受較大拉應力的問題，對比分析了橋面板分區(qū)段澆筑和一次性澆筑兩種施工方法對成橋后組合梁應力的影響，結(jié)果表明采用分區(qū)段澆筑混凝土橋面板能夠有效降低負彎矩區(qū)混凝土橋面板拉應力，提高了橋面板的抗裂性能。 4、研究支點位移法在連續(xù)組合梁橋施工中的應用，對比分析了采用和未采用支點位移法成橋時組合梁應力，結(jié)果表明采用支點位移能使負彎矩區(qū)橋面板混凝土形成一定的壓應力儲備。增加支點升降量使橋面板預壓應力增大同時改善支座處鋼梁下緣的受壓，但同時徐變的卸載作用也呈線性增長。對比分析了同時頂升中支點和按照先后順序頂升中支點兩種方案，結(jié)果表明后者對負彎矩區(qū)的預壓效果更為明顯。
[Abstract]:In recent years, steel-concrete composite structures have been widely used in engineering, but the research on some problems of composite structures is not deep enough. For example, the shrinkage and creep causes the internal force and stress redistribution of the composite structure, which affects the bearing capacity of the structure. For steel-concrete composite continuous beam bridges. The large negative bending moment in the bearing region easily leads to the cracking of the slab tensile stress, etc. In this paper, the construction background of the steel concrete composite continuous beam bridge in Chiawa, Zambia, is 40 m 60 m 40 m. The Midas/Civil finite element analysis program is used to analyze the bridge. Aiming at the internal force and stress redistribution of the composite beam caused by creep, the effect of temperature, the crack width of concrete deck slab under negative bending moment is analyzed. And the construction methods of reducing the tensile stress of the bridge deck in the negative bending moment section are analyzed. The specific work is as follows: 1. The internal force and stress redistribution of concrete creep on composite beam are analyzed, and the influence of loading age and relative humidity on creep effect is analyzed. The effect of concrete shrinkage on creep and the effect of temperature on internal force of composite beam bridge. It is concluded that the temperature stress is mainly caused by the temperature difference between concrete and steel beam. At the same time, the effect of temperature difference is analyzed. When the slab thickness and elastic modulus ratio change, the stress of composite beam changes. 2. The bearing capacity and crack width of bridge deck under negative bending moment are calculated, and the results show that they all meet the requirements of the code, and the crack width of deck slab under different load conditions is calculated. The influence of relative humidity, section height ratio of composite beam and reinforcement ratio of deck slab on the crack width of bridge deck slab is analyzed, and the most unfavorable load affecting the crack width of deck slab under negative bending moment is obtained, and the effect of relative humidity, section height ratio of composite beam and reinforcement ratio of deck slab on the crack width of deck slab is analyzed. 3. Aiming at the problem that the deck slab of continuous composite girder bridge bears large tensile stress in negative bending moment region, the influence of two construction methods on the stress of composite beam after completion of the bridge is compared and analyzed. The results show that the tensile stress of concrete deck slab in negative bending moment region can be reduced effectively, and the crack resistance of concrete deck slab can be improved. 4. The application of fulcrum displacement method in the construction of continuous composite beam bridge is studied, and the stress of composite beam when the bridge is constructed with or without fulcrum displacement method is compared and analyzed. The results show that using fulcrum displacement can make concrete of bridge deck in negative moment region form a certain amount of compressive stress reserve, increase fulcrum lift increase the pre-compression stress of deck slab and improve the compression of the lower edge of steel beam at the support. But at the same time, the unloading effect of creep increases linearly. The results show that the preloading effect of the latter is more obvious in the negative moment region.
【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】：U441;U448.215

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