混凝土箱梁温度场试验及温度效应理论研究

发布时间：2018-01-05 19:40

本文关键词：混凝土箱梁温度场试验及温度效应理论研究　出处：《重庆大学》2014年硕士论文　论文类型：学位论文

【摘要】：混凝土箱形结构中因为材料的传热性能较差，在日照作用下结构中就会形成较大的温差荷载，产生的温差荷载所带来的温度应力是造成混凝土箱梁开裂的重要因素之一。因为混凝土传热问题的复杂性，在现有的混凝土桥梁设计中，有关的理论和计算方法存在一定的缺陷，做了很大程度的简化，然而采用这种经过简化的计算模型和方法，会使温度荷载的取值以及温度应力的计算结果与实际情况之间出现较大的不符。本文从计算理论入手，对混凝土箱梁结构日照温度场及其效应进行了深入的研究，，对计算理论和方法进行了完善和改进，对日照温度荷载的取值进行了分析和探讨。文章以广西桂林地区贵光线幸福源水库双线特大桥为工程背景，选取该桥连续刚构段单室箱梁截面为研究对象，作了如下研究：（1）对课题组进行温度场现场实测的试验仪器和测定方法作了详细说明，通过分析连续高温天气下测得的温度场数据，提出了箱梁顶板、腹板、底板的日照温度场特征。（2）研究了混凝土箱梁结构在日照作用下与周围介质之间的传热机理，系统地阐释了其在热量传递过程中的边界条件，建立了可以反映实际复杂边界条件情况的温度响应的数值分析计算模型。（3）收集整理了计算混凝土单室箱梁结构壁板内部日照温度分布的解析方法，该方法假定沿混凝土结构壁板厚度方向的温度分布具有一维周期性特征，通过对传统的一维热传导微分方程进行数值求解，最终得到傅里叶级数形式的壁板内温度场解析解表达式，在应用中取该解析解的少数几项即可得到足够精确的结果。（4）在实测温度数据的基础上，拟合得到了该地区混凝土箱梁在太阳辐射作用下的最不利温度荷载取值，并与我国现行铁路桥梁设计规范中的温度荷载取值进行了对比分析，提出了在温度荷载取值上的看法和建议。（5）采用合理的假定条件建立了与实际情况相符的计算模型，研究了混凝土箱梁结构温度应力的理论计算方法，该方法将复杂的三维空间问题转化为二维平面问题进行分析，并考虑由于泊松效应引起的各应力分量间的耦合作用，在实际计算中运用结构力学方法即可实现考虑应力分量之间耦合关系的三维温度应力空间分析。结合本文工程背景数据，该方法的计算结果与传统计算方法相比，其精度明显提高。（6）对温度裂缝的成因进行了详细分析，根据裂缝形成的原因提出了桥梁在设计阶段和施工阶段相应的预防控制措施。
[Abstract]:Because of the poor heat transfer performance of the material in the concrete box structure, large temperature difference load will be formed in the structure under the action of sunlight. The temperature stress caused by the temperature difference load is one of the important factors that cause the cracking of concrete box girder. Because of the complexity of the concrete heat transfer problem, it is in the existing concrete bridge design. There are some defects in the theory and calculation method, which is simplified to a great extent. However, the simplified calculation model and method are adopted. It will make the value of temperature load and the calculation result of temperature stress to appear a big discrepancy with the actual situation. This paper starts with the theory of calculation. In this paper, the temperature field of concrete box girder structure and its effect are studied deeply, the calculation theory and method are improved and the value of sunshine temperature load is analyzed and discussed. In this paper, the section of single-chamber box girder in continuous rigid frame section of Guiliangyuan Reservoir in Guilin, Guangxi is selected as the research object, and the following research is done: 1) the test instrument and measurement method of the field temperature field measured by the research group are explained in detail. By analyzing the data of the temperature field measured under the continuous high temperature weather, the top plate and web plate of the box girder are put forward. The characteristics of sunshine temperature field of the bottom plate. 2) the heat transfer mechanism between the concrete box girder structure and the surrounding medium is studied, and the boundary conditions in the heat transfer process are explained systematically. A numerical model for calculating the temperature response of complex boundary conditions is established. The analytical method for calculating the sunshine temperature distribution in concrete single chamber box girder structure is collected and sorted out. The method assumes that the temperature distribution along the thickness direction of concrete structure wall plate has one-dimensional periodicity. Through the numerical solution of the traditional one-dimensional heat conduction differential equation, the analytic expression of the temperature field in the panel is obtained in the form of Fourier series. A few terms of the analytical solution can be obtained with sufficient accuracy in application. Based on the measured temperature data, the most unfavorable temperature load of concrete box girder in this area under solar radiation is obtained by fitting. In addition, this paper compares and analyzes the values of temperature load in the current design code of railway bridges in China, and puts forward some opinions and suggestions on the value of temperature load. 5) the calculation model of concrete box girder structure is established with reasonable assumptions, and the theoretical calculation method of temperature stress of concrete box girder structure is studied. In this method, the complex three-dimensional space problem is transformed into a two-dimensional plane problem, and the coupling between the stress components caused by the Poisson effect is considered. In the actual calculation, the structural mechanics method can be used to realize the three-dimensional thermal stress space analysis considering the coupling relationship between the stress components, combined with the engineering background data in this paper. Compared with the traditional method, the accuracy of the method is improved obviously. 6) the causes of temperature cracks are analyzed in detail, and the corresponding prevention and control measures in the design and construction stages are put forward according to the reasons for the formation of the cracks.
【学位授予单位】：重庆大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U441.5

【参考文献】