【作者】 李全林；

【导师】 王解军；

【作者基本信息】 湖南大学 ， 结构工程， 2004， 硕士

【摘要】 置于外界环境中的桥梁受到外界的影响而产生的温度效应，通常难以准确计算而被简化考虑。现实中许多桥梁事故都被证实与温度效应考虑不周有关，目前各国设计规范关于混凝土箱梁的温差荷载规定不尽一致。本文研究了混凝土箱梁由太阳辐射引起的温度场和温度应力。 本文将太阳辐射对箱梁温度场的影响做了详细的研究，把太阳辐射分为太阳直射、太阳散射和地面反射三种方式，并考虑翼缘对腹板的阴影作用。在本文的研究中具体的工作和成果有： 1．通过对湖南省潭邵高速公路水府庙大桥温度场进行实测，用曲线拟合的方法获得了箱梁竖向温差曲线。 2．利用差分法反算了热力学参数。 3．根据热传导有限单元法原理，使用有限元软件ANSYS建立了二维分析模型，并用APDL编制了宏文件来施加温度荷载和求解，所得计算结果与现场实测的数据进行了比较。 4．分别用平面梁模型和空间模型计算了箱梁温度应力并进行了比较。 5．进行了设计参数研究，包括箱梁翼缘悬臂长度、腹板高度和桥梁轴线方位角对温度场和温度应力的影响，得到了最大横向温差与（腹板高度／翼缘悬臂长度）的曲线图，为设计工作提供了参考。 试验和计算分析都表明，由太阳辐射引起的混凝土箱梁截面上的温度为非线性分布，拟合得到的竖向温差曲线可以用指数函数T_y=23e^-6y和底板附近20cm内线性温差2℃来表示。由于非线性温差而产生的腹板拉应力很大，为了防止混凝土裂缝的发生，设计中必须重视温度效应带来的影响。更多还原

【Abstract】 Temperature effects that arise in bridges exposed to the environmental variables are not easily estimated, and often considered in a simplified way. It is verified that many bridge accidents were caused by temperature effects which should have be took into account carefully, now the design codes of different country on temperature load in concrete box girder have different provisions. The temperature field and temperature stress in concrete box girder bridges that caused by the solar radiation are studied in this thesis.The effect of solar radiation on temperature field in concrete box girder is researched in detail in the thesis which considers that the solar radiation is made up of three component: beam radiation, diffuse radiation and solar radiation diffusely reflected from the ground. The shadow effect of cantilever wing on web is also advised in this thesis. Some work and achievements in the research as follow:1. Based on the measurements of temperature field in shuifumiao bridge of Tan-Shao Expressway in Hunan province, the curve of vertical difference in temperature is obtained with the way of curve fit.2. Different method is used for back-calculating the thermodynamics parameter.3. According to the thermal conduct theory and Finite Element Method(FEM), the analytical model in two-dimension is build, loaded and solved with the help of macro file compiled in APDL and FEM software ANSYS. The result is compared with the data obtained in site measurements.4. The temperature stress in box girder is calculated in two-dimension model and three-dimension model respectively, two results are compared each other too.5. Parametric studies are conducting in order to find the influence of various parameters such as cantilever wing length, web depth and orientation of bridge axis on the temperature field and temperature stress. The curse between maximal horizontal difference in temperature and (web depth/cantilever wing length) is made, which may provide reference in design.Both test and analytical result show that: the temperature distribution in concrete box girder section caused by the solar radiation is nonlinear, the curse of vertical difference in temperature obtained in the way of curse fit can be expressedas exponential function as Ty =23e-6y and the linear difference in temperature 2癈 at the range of 20cm to the bottom slab. The tensile stress resulting from nonlinear difference in temperature in web is strong, so the designer should pay attention to the response of temperature effect in order to protect the concrete from cracking in design.更多还原