日照条件下公路箱形组合梁桥温度场与温度应力分析

发布时间：2019-04-12 19:01

【摘要】：桥梁结构长期暴露在自然环境中日照、环境温度和其他因素影响结构温度场。极端天气,如太阳暴晒或气温骤降,会在结构表面和内部形成较大温度梯度,产生温度应力。温度应力有时甚至比活载产生的应力还大,不少混凝土桥梁因此产生裂缝,甚至严重裂损,给桥梁结构带来巨大危害。研究温度场最直接的办法莫过于实测,然而对于不同地区不同类型的桥梁,在各个测点长期观测非常不经济,也并不实际。有限元仿真模拟,是研究结合梁温度场的手段之一。有限元仿真模型相对实测而言,省时省力。但模型与实际情况是否吻合,成为直接评价模型是否准确的标志。本文以某公路箱形结合梁桥日照温度场实测数据为基础,建立有限元模型。归纳影响温度效应的部分参数,并研究这些参数对于温度效应影响的大小,为设计提供参考。主要研究内容概括如下：综述桥梁日照温度场研究现状。介绍传热学基本理论、建立温度场有限元方程的过程与解出有限元方程的所需要的边界条件。查阅建立有限元模型所需要的各项参数,搜集实际工程中参数的取值范围,并选择合乎本文实例实际情况的取值,建立仿真本文实例的有限元建模。对比有限元模型计算结果与实测数据,检验有限元模型的可行性。从混凝土辐射系数、混凝土导热系数、纬度、日序数、大气透明度、对流换热系数和沥青铺装层厚度等参数中依次选取一个,进行参数分析。代入有限元模型进行运算后,对比并评判该参数对温度场与温度应力的影响大小与规律,并分析造成这些影响的原因。
[Abstract]:Long-term exposure of bridge structure to sunlight, ambient temperature and other factors affect the structural temperature field. Extreme weather, such as sun exposure or sudden temperature drop, will form a large temperature gradient on the surface and interior of the structure, resulting in temperature stress. Sometimes the temperature stress is even larger than the stress produced by live load. Many concrete bridges have cracks and even serious cracks, which bring great harm to the bridge structure. The most direct way to study the temperature field is to measure the temperature field. However, for different types of bridges in different regions, the long-term observation at each measuring point is very uneconomical and impractical. Finite element simulation is one of the methods to study the temperature field of beam. Compared with the actual measurement, the finite element simulation model saves time and effort. However, whether the model is consistent with the actual situation or not has become a sign of the accuracy of the direct evaluation model. Based on the measured data of sunshine temperature field of a highway box-shaped bridge, a finite element model is established in this paper. Some parameters which affect the temperature effect are summarized, and the influence of these parameters on the temperature effect is studied in order to provide reference for the design. The main research contents are summarized as follows: the research status of bridge sunshine temperature field is summarized. This paper introduces the basic theory of heat transfer, the process of establishing the finite element equation of temperature field and the necessary boundary conditions for solving the finite element equation. The parameters needed to establish the finite element model are consulted, the range of the parameters in the actual engineering is collected, and the values in accordance with the actual situation of the example in this paper are selected to establish the finite element model for the simulation of the example in this paper. The feasibility of the finite element model is verified by comparing the calculation results of the finite element model with the measured data. One of the parameters, such as concrete radiation coefficient, concrete thermal conductivity coefficient, latitude, day order, atmospheric transparency, convection heat transfer coefficient and asphalt pavement thickness, is selected to analyze the parameters. After calculation with finite element model, the influence of this parameter on temperature field and temperature stress is compared and evaluated, and the causes of these effects are analyzed.
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U441.5

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