Post-Peak Analysis of Reinforced Concrete Structural Members with Internal Defects

存在内部缺陷的钢筋混凝土结构构件的峰后分析

基本信息

批准号：
14550489
负责人：
MIZUNO Eiji
金额：
$ 2.24万
依托单位：
Chubu University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2002
资助国家：
日本
起止时间：
2002 至 2003
项目状态：
已结题

项目摘要

In the present research, the post-peak behaviors of two types of concrete structural members with the internal defects have been investigated.The one is on the uniaxial compressive behavior of prismatic concrete specimen with internal defects, such as rock-pocket and breeding. The experiments were carried out for the several sizes of concrete specimens with the different sizes of rock-pockets. In the case of experiment on the specimen without the end friction, the reduction in maximum compressive strength is found to be proportional to the projected area of defect to the section of concrete specimen. The 3-D finite element analysis (FEM) with DIANA has given almost the same results as those of experiments. On the other hand, in the case of experiment on the specimen with the end friction, the reduction in maximum compressive strength is found to be more rapid, compared with the case without the end friction. This phenomenon could not be represented numerically even with 3-D FEM analyse … More s, which lead to the same results as those of analysis without the end friction. It has been understood from this analysis that a sever failure pattern may be occurred in the case that the surrounding area of defect portion is constrained to some extent. Therefore, a unified numerical method and modeling are required to give a rise in moderate results for any kinds of boundary conditions.The other is on the flexural behavior of RC beam with internal defects, such as rock-pocket and breaking of hoop ties, The on-point loading experiment have been done for the RC beam (120×180×1,400 mm) with defects at its center. It has been found from experimental work that the existence of rock-pocket affects much on the post-peak behavior as well as the maximum strength, compared with the existence of broken hoop tie. The finite element program FEAP has been used to simulate the experiment, by applying the strain-softening type of constitutive model under the different confining pressures. From the analytical study it has been concluded that the existence of bigger size of rock-pocket, i.e., 0.3 times the beam width, cancels the confining effect from hoop tie and core-concrete becomes almost in a plain condition.Summarizing the present research, it can be said that the reduction in maximum strength as well as the post-peak behavior of concrete structural member should be more carefully considered if the defects exist in an expected failure zone or area of concrete member. Less

在本研究中，已经研究了具有内部缺陷的两种混凝土结构构件的峰值后行为。实验是针对具有不同尺寸的岩石大小的几种尺寸混凝土试样进行的。如果在没有末端摩擦的试样上进行实验，则发现最大抗压强度的降低与缺陷的投影区域成正比，与混凝土标本的截面成正比。戴安娜（Diana）的3-D有限元分析（FEM）给出了与实验的结果几乎相同的结果。另一方面，在标本上具有末端摩擦的试验的情况下，与没有末端摩擦的情况相比，发现最大抗压强度的降低更快。即使通过3-D FEM分析……更多的S，这一现象也无法在数值上得到表示，从而导致与没有最终摩擦的分析结果相同的结果。从该分析中可以理解，如果缺陷部分的周围区域在某种程度上受到约束，则可能会发生断电模式。因此，需要一种统一的数值方法和建模才能在任何形式的边界条件下增强结果。另一个是在带有内部缺陷的RC光束的弯曲行为上，例如岩石口袋和箍绳的破裂，对RC光束进行了启动载荷实验（120×180×180×1,400 mm）。从实验工作中可以发现，与箍束束缚的存在相比，岩袋的存在对峰值行为以及最大强度都影响了。有限的元素程序FEAP已用于通过在不同的狭窄压力下应用构成模型的应变类型来模拟实验。从分析研究中可以得出结论，即岩口袋尺寸的存在，即光束宽度的0.3倍，取消hoop绑带和核心结构的限制效果几乎变得越来越普通。可以说，可以说，最大的强度以及预期的结构成员的言论是，可以说，如果有一个预期的结构成员，则可以仔细地考虑某个裁定的领域。较少的