曲线连续箱梁桥的日照温度效应分析

发布时间：2018-03-02 09:26

  本文关键词： 曲线箱梁桥 梯度温度 力学特性 温度效应　出处：《兰州交通大学》2014年硕士论文　论文类型：学位论文

【摘要】：近年来我国对交通事业的投入越来越大，交通事业得以快速发展，加之城市化进程的加速，曲线梁桥以其适应地形地貌能力强、造型优美等诸多优点在高速公路立体交叉和城市立交中得到了广泛的应用。但是相对于直线梁桥，曲线梁桥具有更加复杂的力学特性。由于混凝土的导热性能比较差，在太阳辐射作用下，其结构内部就会形成非线性的温度梯度，这会使曲线梁桥产生比较大的变形及应力，甚至会引起混凝土结构产生裂缝，影响桥梁使用。目前，曲线梁桥的温度效应研究已经成为桥梁理论及应用研究中的一个重要内容。 本文详细论述了混凝土结构温度效应理论及其影响因素，以平天高速公路后川河2号桥（20m+20m+20m）为工程背景，运用通用有限元软件MIDAS，对三跨曲线连续箱梁桥的温度效应进行了研究。本文主要研究内容和成果如下： (1)相对于直线桥而言，曲线连续梁桥的变形和受力更为复杂。在日照温度荷载作用下，曲线梁桥的竖向位移会更大，且会产生一定的径向位移；曲梁的竖向位移和径向位移都会随曲率半径的增大而减小；不同边跨和中跨比的曲梁，随边跨跨度的减小，边跨竖向位移会不断减小而中跨竖向位移会不断增大。 (2)与直线桥相比，，曲线连续梁桥会产生弯扭耦合作用，在梯度温度作用下，曲梁的扭矩会随曲率半径的增大而减小；不同的边跨和中跨比对曲梁的扭矩有较大影响，在边跨部分，虽然扭矩随边跨的减小而减小，但中墩位置的突变扭矩就会越大；全抗扭支承方式有利于曲梁整体扭矩的分散和卸载，中间点铰支承形式的曲梁扭矩会累积传递到曲梁两端，在曲梁半径较大时，会使内侧支座脱空，因此，在曲梁设计时，应予以充分考虑。 (3)从实体单元所建模型的研究分析中可以得出：在梯度温度荷载所产生的各应力分量中，纵向应力和横向应力对桥梁的影响较大，尤其是桥梁顶板或顶板与腹板相交的部位产生的拉应力会较大，甚至会超过混凝土的抗拉设计强度值，在桥梁设计时应加强这些位置的配筋，并进行抗裂验算，确保桥梁具有足够的耐久性与安全性。 (4)在梯度温度荷载和自重作用下，曲梁的支座反力呈现如下特点：曲梁的外侧支座反力大于内侧支座；边墩的支座反力小于中墩支座；随这曲率半径的增大，曲梁外侧支座反力逐渐减小，内侧支座反力先增大后减小至内外侧支座反力基本相等。
[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.
【学位授予单位】：兰州交通大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U441.5;U448.213

【参考文献】

中国期刊全文数据库 前3条

1 王毅;叶见曙;;温度梯度对混凝土曲线箱梁影响的计算方法[J];东南大学学报(自然科学版);2005年06期

2 屈兆均;;用有限单元法解温度应力的计算原理[J];桥梁建设;1982年03期

3 张元海,李乔;桥梁结构日照温差二次力及温度应力计算方法研究[J];中国公路学报;2004年01期

本文编号：1555939