太阳辐射作用下混凝土箱梁桥温度分布和温度应力的研究

发布时间：2018-07-09 14:23

本文选题：混凝土箱梁 + 太阳辐射　；参考：《天津大学》2014年硕士论文

【摘要】：混凝土桥梁在外界环境尤其是太阳辐射的作用下会产生非线性温度分布，，由此引起的桥梁上部结构的应力与外荷载引起的效应相当，温度应力成为混凝土箱梁开裂的重要原因之一。但是由于问题的复杂性，在目前的桥梁设计中通常采用相对简化的理论和模型来计算温度效应，但简化的模型和计算方法有时会使计算结果与实际情况存在较大误差。本文针对太阳辐射作用下混凝土箱梁的温度场和温度应力计算方法展开了以下几方面的研究： 1.根据天文学以及传热学相关理论知识建立了混凝土箱梁日照温度场分析模型，并在应用一种实用太阳辐射强度计算方法的基础上系统地建立了热传递模型及其对应的边界条件。据此编制了可以针对箱梁日照条件下温度场进行分析的有限元计算接口程序，通过计算结果阐明了混凝土箱梁温度分布的特点。 2.为了研究各种环境因素对箱梁温度场的影响，并找出关键影响因素，本文通过改变程序中各参数的取值对箱梁日照温度场分布的影响因素进行了详细的分析，如太阳辐射强度、外界气温、桥梁走向、结构尺寸及材料参数等。经研究发现，太阳辐射强度是最关键影响因素，其他因素次之。 3.混凝土箱梁桥的温度应力由温度自应力和温度次应力组成。本文基于一个数学积分性质采用一种考虑泊松效应的方法来计算温度自应力，温度次应力则通过结构力学方法获得。公式推导过程和计算结果都表明：考虑泊松效应会对温度自应力计算结果有较大影响，传统的计算方法有时是偏不安全的。本文应用有限元方法实现了太阳辐射作用下的混凝土箱梁温度场的计算，并分析了其关键影响因素，又应用一种考虑泊松效应的温度应力计算法对箱梁温度应力的大小和特点进行了研究，实现了混凝土箱梁温度效应的分析。本文研究内容与结论可为桥梁设计中温度效应的计算提供一定的参考。
[Abstract]:Concrete bridge will produce nonlinear temperature distribution under the action of external environment, especially solar radiation, and the stress of the superstructure caused by this will be equivalent to the effect caused by external load. Thermal stress has become one of the important reasons for cracking of concrete box girder. However, due to the complexity of the problem, the relatively simplified theory and model are usually used to calculate the temperature effect in the current bridge design. In this paper, the calculation methods of temperature field and temperature stress of concrete box girder under solar radiation are studied as follows: 1. Based on the theoretical knowledge of astronomy and heat transfer, the analytical model of sunshine temperature field of concrete box girder is established, and the heat transfer model and its corresponding boundary conditions are established systematically on the basis of a practical solar radiation intensity calculation method. Based on this, a finite element calculation interface program for temperature field analysis of box girder under sunshine condition is developed. The characteristics of temperature distribution of concrete box girder are clarified by the result of calculation. 2. In order to study the influence of various environmental factors on the temperature field of box girder and find out the key factors, this paper analyzes in detail the factors affecting the distribution of temperature field of box girder by changing the values of each parameter in the program, such as the intensity of solar radiation. Outside temperature, bridge direction, structure size and material parameters. The results show that solar radiation intensity is the most important factor, followed by other factors. 3. 3. The temperature stress of concrete box girder bridge consists of self-stress and sub-stress. In this paper, based on a mathematical integral property, a method considering Poisson effect is used to calculate the temperature self-stress, and the temperature secondary stress is obtained by the structural mechanics method. Both the formula derivation process and the calculation results show that considering Poisson effect will have a great influence on the calculation results of temperature self-stress, and the traditional calculation method is sometimes unsafe. In this paper, the finite element method is used to calculate the temperature field of concrete box girder under solar radiation, and the key influencing factors are analyzed. A temperature stress calculation method considering Poisson effect is applied to study the size and characteristics of the temperature stress of the box girder, and the analysis of the temperature effect of concrete box girder is realized. The contents and conclusions of this paper can provide some references for the calculation of temperature effect in bridge design.
【学位授予单位】：天津大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U441.5;U448.213

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