大跨径连续刚构桥零号块水化热温度效应及温控措施研究

发布时间：2018-03-21 12:07

本文选题：零号块　切入点：高强混凝土　出处：《长安大学》2015年硕士论文　论文类型：学位论文

【摘要】：随着对桥梁温度应力研究不断深入,箱梁零号块水化热问题受到了越来越多的关注,在浇筑前期零号块由于水化热会使箱梁内外产生较大的温度梯度,从而形成的温度应力极易造成温度裂缝,而零号块为主要的受力构件,其质量的好坏直接关系到桥梁的施工安全和全桥的耐久性。本文参阅了大量与水化热温度效应相关的专业学术论文和书籍,并进行归纳总结,以一座主跨为75m的三跨连续刚构桥的零号块为研究对象,具体工作和研究成果如下:(1)通过现场监测的大量数据对零号块水化热温度场的变化规律进行研究,并分析形成原因。(2)用有限元分析软件MIDAS/FEA建立零号块块段的实体模型,模拟水化热温度场的发展历程,结合实测数据对高强混凝土水化热温度场的变化规律进行总结,发现现有规范以及有限元软件在计算高强混凝土水化热方面与实际存在较大差异,同时根据研究成果对所用高强混凝土的导温系数进行修正,使有限元分析计算结果与实测值基本吻合,以便为该地区同类型桥梁的设计和施工提供参考。(3)为达到控制温度裂缝的目的,根据热传导理论以及实测数据发现的混凝土水化热规律,对原施工方案进行优化,提出了两种切实可行的温控方案,利用有限元仿真分析表明,这两种优化方案可以显著降低温度峰值,减小温度裂缝的出现。(4)最后对水化热温控措施进行探讨,分别从设计和施工提出了具体可行的温控措施。
[Abstract]:With the development of the research on the temperature stress of the bridge, the hydration heat problem of the box girder zero block has been paid more and more attention. The hydration heat of the zero block in the early stage of pouring will cause a large temperature gradient inside and outside the box girder. As a result, the resulting temperature stress is easy to cause temperature cracks, and the zero block is the main force member. The quality of the bridge is directly related to the safety of the bridge construction and the durability of the whole bridge. In this paper, a large number of professional academic papers and books related to the effect of hydration heat temperature are reviewed and summarized. Taking the zero block of a three-span continuous rigid frame bridge with a main span of 75 m as the research object, the concrete work and research results are as follows: 1) the variation of hydration heat temperature field of zero block is studied through a large number of data monitored in the field. The reason of formation is analyzed. (2) the solid model of block zero is established by using finite element analysis software MIDAS/FEA, the development course of hydration heat temperature field is simulated, and the variation law of hydration heat temperature field of high strength concrete is summarized combining with the measured data. It is found that the existing codes and finite element software are quite different from the actual ones in calculating the hydration heat of high strength concrete. At the same time, according to the research results, the temperature conductivity coefficient of the high strength concrete is modified. The results of finite element analysis are in good agreement with the measured values, so as to provide a reference for the design and construction of the same type of bridges in this area, so as to achieve the purpose of controlling temperature cracks. According to the heat conduction theory and the heat law of concrete hydration found by the measured data, the original construction scheme is optimized, and two feasible temperature control schemes are put forward. The finite element simulation analysis shows that, These two optimization schemes can significantly reduce the temperature peak value and reduce the appearance of temperature cracks. Finally, the hydration heat temperature control measures are discussed, and the concrete and feasible temperature control measures are put forward from the design and construction.
【学位授予单位】：长安大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U448.23;U445.57

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