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  本文選題：大跨徑梁橋　切入點：結(jié)構(gòu)長期性能　出處：《長安大學》2014年碩士論文　論文類型：學位論文

【摘要】：橋梁作為跨越路線障礙的主要構(gòu)造物在交通基礎(chǔ)設(shè)施建設(shè)中被廣泛使用，其中大跨徑預應力混凝土連續(xù)梁橋在我國已建橋梁中占有相當大的比例。近幾年發(fā)現(xiàn)，大跨徑梁橋在服役若干年后就發(fā)生跨中下?lián)线^大，梁體產(chǎn)生裂縫等病害，本文首次從施工階段對橋梁結(jié)構(gòu)長期力學性能影響的角度考慮這個問題。首先對施工階段的誤差進行了合理分類，，其次考慮了不同種類的誤差對橋梁結(jié)構(gòu)長期工作性能的影響，以期對橋梁的施工和設(shè)計提出合理建議。 施工階段對結(jié)構(gòu)的影響可以分為施工質(zhì)量問題和施工誤差，施工質(zhì)量問題又可以分為已經(jīng)暴露出的質(zhì)量問題和潛在的質(zhì)量問題；而施工誤差又可以分為規(guī)范做出規(guī)定的誤差與規(guī)范未做出規(guī)定的誤差，不同類型的施工誤差對橋梁結(jié)構(gòu)長期力學性能影響方式與程度不同。本文對與收縮徐變相關(guān)的兩項誤差以及合龍高差進行了分析。 不同的收縮徐變模型計算的結(jié)構(gòu)長期內(nèi)力與變形差別較大，我國現(xiàn)行規(guī)范計算值總體比其他規(guī)范要小。由于目前非標準條件下混凝土收縮徐變規(guī)律研究較少，因此不排除這也是橋梁長期病害的一個因素。 加載齡期對橋梁結(jié)構(gòu)長期內(nèi)力與變形存在影響：就大跨徑梁橋而言，主跨相比邊跨更加敏感，主墩墩頂應力比邊墩墩頂應力更加敏感，理論數(shù)據(jù)表明由在我國現(xiàn)行規(guī)范下由加載齡期導致的結(jié)構(gòu)性能與設(shè)計值的偏差經(jīng)過十年收縮徐變后在5%以內(nèi)。 合龍高差對橋梁結(jié)構(gòu)長期內(nèi)力變形的影響隨強迫合龍高差的增大而增大，理論分析表明，強迫合龍對跨中長期撓度控制是有益的，但對跨中兩側(cè)結(jié)構(gòu)影響不同：對被壓重一側(cè)，強迫合龍使得邊跨跨中上撓、墩頂壓應力減小，另一側(cè)則相反，總體上來說強迫合龍對被壓重一側(cè)影響較大。數(shù)據(jù)表明對于百米跨徑梁橋當強迫高差小于5cm時，可以保證其對結(jié)構(gòu)長期力學性能的影響小于5%。
[Abstract]:Bridge is widely used in the construction of transportation infrastructure as the main structure of crossing route obstacle, in which the long-span prestressed concrete continuous beam bridge occupies a large proportion of the bridges that have been built in our country. After several years of service, long span beam bridges suffer from diseases such as excessive span deflection and cracks in the beam body. This paper considers this problem for the first time from the point of view of the influence of the construction stage on the long-term mechanical performance of the bridge structure. Firstly, the errors in the construction stage are classified reasonably, and then the influence of different kinds of errors on the long-term working performance of the bridge structure is considered. In order to put forward reasonable suggestions on the construction and design of the bridge. The influence of construction stage on structure can be divided into construction quality problems and construction errors, and construction quality problems can be divided into exposed quality problems and potential quality problems. And the construction error can be divided into the error specified in the code and the error not specified in the code. Different types of construction errors affect the long-term mechanical properties of bridge structures in different ways and degrees. In this paper, two errors related to shrinkage and creep and the height difference of closure are analyzed. The long-term internal forces and deformation of structures calculated by different shrinkage and creep models are quite different, and the calculated values of current codes in China are generally smaller than those of other codes. Because of the lack of research on shrinkage and creep laws of concrete under non-standard conditions at present, Therefore, it is also a factor of long-term disease of bridge. The effect of loading age on the long-term internal force and deformation of bridge structure is as follows: for long-span beam bridges, the main span is more sensitive than the side span, and the stress at the top of the main pier is more sensitive than the top stress of the side pier. The theoretical data show that the deviation between the structural performance and the design value caused by the loading age is less than 5% after ten years of shrinkage and creep. The influence of closing height difference on the long-term internal force deformation of bridge structure increases with the increase of forced closure height difference. Theoretical analysis shows that forced closure is beneficial to the control of mid-long span deflection. However, the effects on the middle and middle side of the span are different: for the compressed side, the forced closure causes the upper deflection of the middle span of the side span, the pressure stress at the top of the pier decreases, and the other side is opposite. The data show that when the forced height difference is less than 5cm, the influence of forced closure on the long-term mechanical properties of the bridge is less than 5cm.
【學位授予單位】：長安大學
【學位級別】：碩士
【學位授予年份】：2014
【分類號】：U445;U448.215

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