考虑温度影响的钢筋混凝土结构施工过程安全分析与计算机实现

发布时间：2018-06-25 16:04

本文选题：钢筋混凝土结构 + 施工期　；参考：《上海交通大学》2014年博士论文

【摘要】：钢筋混凝土结构在施工阶段实际上是一个部分完成的结构和模板支撑系统构成的“时变结构”。经验表明，随着模板支撑系统的撤换这种结构很可能出现在整个“生命周期”中最不安全的受力状态，，从而引发事故。为了控制这种事故的发生，自上个世纪60年代开始国内外做了大量的研究，探索了一些便于施工安全控制的简明的计算方法。美国学者P. Grundy和A. Kabaila提出了简化手算结构分析方法，此后，我国学者刘西拉教授于1985年建立了施工期结构分析的三维有限元法——精化方法。简化方法和精化方法是钢筋混凝土结构施工期荷载传递研究中的两个里程碑式的计算模型。随着现代施工技术的不断提高，钢支撑在钢筋混凝土结构施工中逐渐取代了木支撑得到了越来越广泛的使用。而一些实测研究表明，钢支撑在昼夜温差作用下热胀冷缩对施工期结构荷载传递的影响不能被忽略。为了研究温差对施工期钢筋混凝土结构荷载传递的影响规律，本文作了如下研究工作。首先，在结构模型方面，本文在国内外相关研究的基础上，增加考虑施工日夜环境温差的影响，统一了现有的钢筋混凝土框架，板柱和墙板结构在施工期的结构模型和分析方法，模型考虑了混凝土强度和弹性模量随龄期增长的影响。接着本文使用二维非稳态热传导方程建立了昼夜温差和钢支撑同混凝土结构柱子之间的温差的相互关系，并据此将温度的影响以广义的荷载添加到结构中。同时，本文还在模型中考虑了钢支撑上下木垫块引起支撑整体抗压刚度的影响。其次，本文根据前面的结构模型和温度模型编制了相应的“考虑温度影响的施工过程安全分析”（Safety Analysis during Construction consideringTemperature，SACT）应用软件。SACT能运行于windows2000，window XP，windows7等多个操作系统，可使用Excel2000，Excel2003，Excel2007，Excel2010等多个版本进行数据输入和输出。SACT采用MFC（Microsoft FoundationClasses）应用程序框架编写图形界面，能进行施工操作的逐步模拟和计算。SACT软件在编制过程中体现了模型中所考虑的温差以及钢支撑上下木垫块对施工期荷载传递的影响。通过同现场实测数据的比较验证了SACT计算结果的准确性和适用性。此外，文章还讨论了温差大小对施工期荷载传递的影响，揭示了不同昼夜温差影响下的钢筋混凝土结构施工期荷载传递规律，并建议了临界温差值，当昼夜温差大与临界温差时，温差对荷载传递的影响不应被忽略。最后，本论文还分析讨论了在温度影响下施工周期，钢支撑层数以及支撑刚度（木垫块厚度）对施工期混凝土结构荷载传递的影响，分析并得出了一些相关规律，提出了提高施工安全性的一些改进措施。这些结论对现场施工人员有一定的借鉴意义。
[Abstract]:The reinforced concrete structure is actually a "time-varying structure" composed of partially completed structure and formwork support system in the construction stage. Experience shows that with the removal of the formwork support system, the structure is likely to appear in the most unsafe stress state throughout the "life cycle", thus causing accidents. In order to control the occurrence of this kind of accident, a lot of research has been done at home and abroad since the 1960s, and some simple calculation methods which are convenient for construction safety control have been explored. American scholars P.Grundy and A. Kabaila proposed a simplified manual structural analysis method. After that, Professor Liu Sila, a Chinese scholar, established a three-dimensional finite element method-refined method for structural analysis during construction period in 1985. Simplified method and refined method are two milestone calculation models in the research of load transfer of reinforced concrete structure during construction period. With the development of modern construction technology, steel braces have been used more and more widely in the construction of reinforced concrete structures. Some experimental studies show that the influence of thermal expansion and contraction of steel braces on the load transfer during construction period can not be ignored under the effect of diurnal temperature difference. In order to study the effect of temperature difference on load transfer of reinforced concrete structure during construction period, the following research work has been done in this paper. First of all, in the structural model, based on the relevant research at home and abroad, this paper adds consideration to the effect of temperature difference in the environment of construction day and night, unifying the existing reinforced concrete frame. The structural model and analysis method of slab-column and wallboard structure during the construction period. The influence of concrete strength and elastic modulus with age is considered in the model. Then the relationship between the diurnal temperature difference and the temperature difference between steel braces and concrete columns is established by using the two-dimensional unsteady heat conduction equation and the influence of temperature is added to the structure by generalized load. At the same time, the influence of steel bracing upper and lower wood cushion on the overall compressive stiffness of the bracing is also considered in the model. Secondly, according to the previous structural model and temperature model, the corresponding application software of Safety Analysis during Construction considering temperature (SACT). SACT can run on Windows 2000 window XP windows 7 and other operating systems. We can use Excel 2003 / Excel 2007 / Excel 2010 to input and output data. SACT uses MFC (Microsoft Foundation classes) application framework to write graphical interface. The software SACT can simulate and calculate the construction operation step by step. The influence of the temperature difference considered in the model and the upper and lower wood cushions of steel braces on the load transfer during the construction period is embodied in the software of SACT. The accuracy and applicability of SACT calculation results are verified by comparison with field measured data. In addition, the influence of temperature difference on load transfer during construction is discussed, and the law of load transfer of reinforced concrete structure under different temperature difference between day and night is revealed, and the critical temperature difference is suggested. When the temperature difference between day and night is large and critical temperature difference, the influence of temperature difference on load transfer should not be ignored. Finally, under the influence of temperature, the influence of the construction period, the number of steel bracing layers and the support stiffness (the thickness of wood cushion) on the load transfer of concrete structure during construction period is analyzed and discussed, and some relevant laws are obtained. Some measures to improve the safety of construction are put forward. These conclusions have certain reference significance to the field construction personnel.
【学位授予单位】：上海交通大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TU755

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