现行规范中独立基础受弯承载能力验算方法的探讨

发布时间：2019-06-20 13:31

【摘要】：地基和基础是建筑物的根基,又属于地下隐蔽工程,它的勘察、设计和施工质量直接关系着建筑物的安危。钢筋混凝土柱下独立基础是上业、民用建筑中广泛采用的一种基础形式,现行的《建筑地基基础设计规范》(GB50007-2011)中对柱下独立基础受弯承载能力的计算方法存在一些实际问题。本文首先介绍了我国规范中关于柱下独立基础受弯承载力计算方法的发展过程,通过受力时的平衡分析,利用数学方法,对我国现行的及曾使用的《地基基础设计规范》中独立基础底板受弯计算公式进行了推导。在此基础上,将地基假设为无限多个小桩,利用现行的《建筑桩基技术规范》(JGJ94-2008)中柱下独立承台受弯的计算公式进行了计算对比,分析了它们之间的差异。然后,对现有规范公式的计算方法本身进行讨论。指出现有计算公式按梯形破坏机构模式计算的不合适之处；在此基础上.对柱下独立基础进行塑性铰线分析,应用塑性铰线法推导出柱下独立基础的极限承载弯矩；根据以上分析按基础受弯井形破坏机构模式的计算方法建立柱下独立基础底板受弯承载能力新的计算公式。最后,对本文所推导出的新的计算公式进行安全性评价。结合算例及本文作者的实际工程设计实例,对比两种计算公式的计算结果,根据实际配筋研究按照现行规范公式计算配筋结果是否安全。并尝试推导出二者公式的“临界点”,得出在哪些边界条件下,按规范公式计算并设计配筋的独立基础将可能偏于不安全。
[Abstract]:The foundation and foundation are the foundation of the building and belong to the underground hidden engineering. Its investigation, design and construction quality are directly related to the safety of the building. The independent foundation under reinforced concrete column is a kind of foundation form widely used in civil buildings. There are some practical problems in the current Code for Design of Building Foundation (GB50007-2011) for calculating the bending bearing capacity of independent foundation under column. This paper first introduces the development process of the calculation method of the bending capacity of the independent foundation under the column in the code of our country, and deduces the calculation formula of the bending capacity of the bottom plate of the independent foundation in the Code for the Design of the Foundation in our country by means of the balance analysis and the mathematical method. On this basis, the foundation is assumed to be an infinite number of small piles, and the calculation and comparison of the bending of the independent cap under the middle column in the current Technical Code for Building pile Foundation (JGJ94-2008) are carried out, and the differences between them are analyzed. Then, the calculation method of the existing specification formula itself is discussed. It is pointed out that the existing formulas are not suitable for calculation according to the mode of ladder failure mechanism, on the basis of which, it is pointed out that the existing formulas are not suitable for the calculation of ladder failure mechanism. The plastic hinge line analysis of the independent foundation under the column is carried out, and the ultimate bearing moment of the independent foundation under the column is derived by using the plastic hinge method. According to the above analysis, a new formula for calculating the bending bearing capacity of the bottom plate of the independent foundation under the column is established according to the calculation method of the bending well failure mechanism mode of the foundation. Finally, the security of the new formula derived in this paper is evaluated. Combined with an example and an actual engineering design example of this paper, the calculation results of the two formulas are compared, and the safety of calculating the reinforcement results according to the current code formula is studied according to the actual reinforcement formula. The "critical point" of the two formulas is deduced, and it is concluded that under which boundary conditions, the independent foundation of reinforcement calculated and designed according to the standard formula may be unsafe.
【学位授予单位】：东南大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU470

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