本文關(guān)鍵詞： 曲線箱梁橋 梯度溫度 力學特性 溫度效應　出處：《蘭州交通大學》2014年碩士論文　論文類型：學位論文

【摘要】：近年來我國對交通事業(yè)的投入越來越大，交通事業(yè)得以快速發(fā)展，加之城市化進程的加速，曲線梁橋以其適應地形地貌能力強、造型優(yōu)美等諸多優(yōu)點在高速公路立體交叉和城市立交中得到了廣泛的應用。但是相對于直線梁橋，曲線梁橋具有更加復雜的力學特性。由于混凝土的導熱性能比較差，在太陽輻射作用下，其結(jié)構(gòu)內(nèi)部就會形成非線性的溫度梯度，這會使曲線梁橋產(chǎn)生比較大的變形及應力，甚至會引起混凝土結(jié)構(gòu)產(chǎn)生裂縫，影響橋梁使用。目前，曲線梁橋的溫度效應研究已經(jīng)成為橋梁理論及應用研究中的一個重要內(nèi)容。 本文詳細論述了混凝土結(jié)構(gòu)溫度效應理論及其影響因素，以平天高速公路后川河2號橋（20m+20m+20m）為工程背景，運用通用有限元軟件MIDAS，對三跨曲線連續(xù)箱梁橋的溫度效應進行了研究。本文主要研究內(nèi)容和成果如下： (1)相對于直線橋而言，曲線連續(xù)梁橋的變形和受力更為復雜。在日照溫度荷載作用下，曲線梁橋的豎向位移會更大，且會產(chǎn)生一定的徑向位移；曲梁的豎向位移和徑向位移都會隨曲率半徑的增大而減��；不同邊跨和中跨比的曲梁，隨邊跨跨度的減小，邊跨豎向位移會不斷減小而中跨豎向位移會不斷增大。 (2)與直線橋相比，，曲線連續(xù)梁橋會產(chǎn)生彎扭耦合作用，在梯度溫度作用下，曲梁的扭矩會隨曲率半徑的增大而減��；不同的邊跨和中跨比對曲梁的扭矩有較大影響，在邊跨部分，雖然扭矩隨邊跨的減小而減小，但中墩位置的突變扭矩就會越大；全抗扭支承方式有利于曲梁整體扭矩的分散和卸載，中間點鉸支承形式的曲梁扭矩會累積傳遞到曲梁兩端，在曲梁半徑較大時，會使內(nèi)側(cè)支座脫空，因此，在曲梁設計時，應予以充分考慮。 (3)從實體單元所建模型的研究分析中可以得出：在梯度溫度荷載所產(chǎn)生的各應力分量中，縱向應力和橫向應力對橋梁的影響較大，尤其是橋梁頂板或頂板與腹板相交的部位產(chǎn)生的拉應力會較大，甚至會超過混凝土的抗拉設計強度值，在橋梁設計時應加強這些位置的配筋，并進行抗裂驗算，確保橋梁具有足夠的耐久性與安全性。 (4)在梯度溫度荷載和自重作用下，曲梁的支座反力呈現(xiàn)如下特點：曲梁的外側(cè)支座反力大于內(nèi)側(cè)支座；邊墩的支座反力小于中墩支座；隨這曲率半徑的增大，曲梁外側(cè)支座反力逐漸減小，內(nèi)側(cè)支座反力先增大后減小至內(nèi)外側(cè)支座反力基本相等。
[Abstract]:In recent years, our country has invested more and more in the transportation industry, and the transportation industry has developed rapidly. In addition, with the acceleration of the urbanization process, the curved girder bridges have strong ability to adapt to the topography and geomorphology. Many advantages, such as graceful shape, have been widely used in expressway interchange and urban interchange. However, compared with linear beam bridges, curved girder bridges have more complex mechanical properties. Because of the poor thermal conductivity of concrete, Under the action of solar radiation, a nonlinear temperature gradient will be formed inside the structure, which will make the curved girder bridge produce relatively large deformation and stress, and even cause cracks in concrete structure, which will affect the use of the bridge. The study of temperature effect of curved girder bridge has become an important content in bridge theory and application. In this paper, the theory of temperature effect of concrete structure and its influencing factors are discussed in detail. The engineering background is based on the 20m 20m 20m bridge of Houchuan River No.2 Bridge of Pingtian Expressway. The temperature effect of a three-span curved continuous box girder bridge is studied by using the universal finite element software Midas. The main contents and results of this paper are as follows:. 1) compared with the linear bridge, the deformation and force of the curved continuous beam bridge are more complicated. The vertical displacement of the curved beam bridge will be larger and will produce a certain radial displacement under the action of sunshine temperature load. The vertical displacement and radial displacement of curved beam will decrease with the increase of curvature radius, and the vertical displacement of edge span will decrease and the vertical displacement of middle span will increase with the decrease of span of side span for curved beam with different side span and mid-span ratio. Compared with the linear bridge, the curved continuous beam bridge will produce the coupling effect of bending and torsion, and the torsion of curved beam will decrease with the increase of curvature radius under the action of gradient temperature, and the torque of curved beam will be greatly affected by different ratio of side span and middle span. In the side span part, although the torque decreases with the decrease of the side span, the sudden torque of the middle pier position will increase, and the full torsional supporting mode is advantageous to the dispersion and unloading of the overall torque of the curved beam. The torsion of curved beam with intermediate hinge bearing form will be transferred to both ends of curved beam, and when the radius of curved beam is large, the inner support will be empty. Therefore, in the design of curved beam, it should be taken into full consideration. 3) from the research and analysis of the model built by the solid element, it can be concluded that the longitudinal stress and the transverse stress have a great influence on the bridge among the stress components produced by the gradient temperature load. Especially, the tensile stress produced by the roof of the bridge or the place where the roof of the bridge intersects with the web plate will be larger, even exceeding the tensile design strength value of concrete. In the design of the bridge, the reinforcement at these positions should be strengthened and the crack resistance checking calculation should be carried out. Ensure adequate durability and safety of bridges. 4) under the action of gradient temperature load and deadweight, the reaction force of the support of curved beam is as follows: the reaction force of the lateral support of curved beam is greater than that of the inner support, the reaction force of side pier is smaller than that of the support of middle pier, and with the increase of the radius of curvature, The reaction force of the lateral support of the curved beam decreases gradually, and the reaction force of the inner support increases first and then decreases to the same reaction force of the inner and outer side of the support.
【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】：U441.5;U448.213

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