山区桥梁空心薄壁高墩日照温度场及温度效应研究

发布时间：2018-05-16 20:06

本文选题：空心薄壁高墩 + 日照温度场　；参考：《长沙理工大学》2015年硕士论文

【摘要】：空心薄壁高墩作为山区大跨径桥梁重要的下部结构,置于外界环境中,受到太阳照射、大气气温等的影响,其结构内外表面的温度发生变化,但由于混凝土的导热性能差,导致空心薄壁高墩的内外表面温度变化速度不一致,形成较大的温差,进而形成较大的温差应力和位移。有时温度应力和位移过大,会引起裂缝或墩身歪斜,对桥梁的安全和正常运行造成严重的影响。因日照温度效应引起的桥梁破坏事故越来越多,因此,迫切需要研究空心墩的温度效应,来防范和降低这种作用对结构的破坏。本文以工程实例为背景,研究了山区桥梁的空心薄壁高墩的温度分布和效应。主要工作和所得结论如下:(1)翻阅大量国内外文献,较详细的介绍了空心薄壁高墩的温度形成机理、温度分布的影响因素以及几种温度荷载的特点,介绍了计算空心薄壁高墩温度场、温度效应的方法,以及求解其所需的热传导边界条件的计算方法。(2)介绍背景桥梁的基本资料,确定现场实测方案,分析高墩的温度场分布,根据实测资料,结合相关规范和理论,用Mat Lab回归拟合出高墩的指数温度梯度曲线,提出了适合桥址地区的空心薄壁墩的温度梯度模式:桥墩横向T_x=17.82e~(-8.423x) ,桥墩纵向T_y=17.61e~(9.428y),,并对比分析拟合公式和实测数据的差别,显示数据吻合较好。(3)结合桥址地理数据和气象条件,利用大型通用有限元软件Midas FEA建立空心墩截面温度模型,分析桥墩的温度场,对比分析计算结果、实测数据以及拟合的温差分布曲线的差别,结果显示3条曲线基本吻合,证明有限元软件模拟的实用性。用Midas FEA建立空心薄壁墩的全墩模型,分析了日照温差应力和日照引起的桥墩位移,显示桥墩温差应力和位移都比较大,对桥墩的线形和安全都有较大的威胁,不容忽视。因此在桥梁的设计、施工以及监控中必须考虑日照温度的影响。
[Abstract]:Hollow thin-walled high pier, as an important substructure of long-span bridge in mountainous area, is placed in the outside environment and affected by solar radiation and atmospheric temperature. However, the inner and outer surface temperature of the structure changes, but the thermal conductivity of concrete is poor. The inner and outer surface temperature of the hollow thin-walled high pier is not consistent, resulting in a larger temperature difference, and then a larger temperature difference stress and displacement. Sometimes excessive thermal stress and displacement will cause cracks or skew of pier body, which will seriously affect the safety and normal operation of the bridge. There are more and more bridge damage accidents caused by sunshine temperature effect, so it is urgent to study the temperature effect of hollow pier in order to prevent and reduce the damage to the structure. In this paper, the temperature distribution and effect of hollow thin-walled high pier of mountain bridge are studied based on engineering examples. The main work and conclusions are as follows: (1) reviewing a large number of domestic and foreign literatures, the temperature forming mechanism of hollow thin-walled high pier, the influencing factors of temperature distribution and the characteristics of several kinds of temperature loads are introduced in detail. This paper introduces the method of calculating temperature field and temperature effect of hollow thin-walled high pier, and the calculation method of heat conduction boundary condition needed for it. It introduces the basic data of background bridge, determines the field measurement scheme, and analyzes the temperature field distribution of high pier. According to the measured data, combined with relevant codes and theories, the exponential temperature gradient curve of high piers was fitted by Mat Lab regression, and the temperature gradient model of hollow thin-walled piers suitable for bridge site was put forward: transverse T _ XD _ (17.82) E ~ (-8.423x) of bridge piers. The longitudinal Tyx 17.61e of piers is 9.428yr. The difference between the fitting formula and the measured data shows that the data are in good agreement with the geographic data and meteorological conditions of the bridge site, and the temperature model of the hollow pier section is established by using the large-scale finite element software Midas FEA. The temperature field of bridge piers is analyzed, and the difference of the calculated results, the measured data and the fitted temperature difference distribution curves is compared. The results show that the three curves are basically consistent, which proves the practicability of finite element software simulation. The model of full pier of hollow thin-walled pier is established by Midas FEA, and the temperature difference stress and the displacement of bridge pier caused by sunshine are analyzed. The results show that the temperature difference stress and displacement of bridge pier are relatively large, which is a great threat to the alignment and safety of bridge pier, and can not be ignored. Therefore, the influence of sunshine temperature must be taken into account in the design, construction and monitoring of bridges.
【学位授予单位】：长沙理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U441.5

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