Study on Shear Design of Underground Concrete Structures

地下混凝土结构抗剪设计研究

基本信息

批准号：
02650329
负责人：
KAKUTA Yoshio
金额：
$ 1.41万
依托单位：
Hokkaido University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1990
资助国家：
日本
起止时间：
1990 至 1991
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-02650329/
关键词：
Reinforced concrete Shear Ultimate strength Underground structure 限界状態設計法

项目摘要

Although many underground concrete structures have been constructed till now, the design of such structures was based on the results of research on the structures on earth. However, it is considered that the underground structures subjected to distributed loads due to earth pressure have more profitable property than the structures with concentrated loads. As the underground structures generally consist of plane members, it is desired that the required strength and ductility will be obtained without shear reinforcement. Furthermore, restraint action of the earth may be expected at the ultimate limit state of the structures. The purpose of this study was to establish reasonable design method for shear of underground concrete structures. To achieve this purpose experiments of reinforced concrete beams with contraflexure point and reinforced concrete slabs were made.The principal results obtained in this study are as follows. 1)Modes of shear failure of reinforced concrete members with contraflexure point can be classified into three types ; (a)diagonal tension failure by a single diagonal crack, (b)diagonal tension failure by two diagonal cracks, and(c)compression failure of concrete in the direction connecting load point and support point. 2)Ultimate strength for failure mode(a)can be calculated by using corresponding shear span. 3)Ultimate strength for mode(b)can be calculated as the larger of the calculated values for each shear span bordering contraflexure point. 4)Contraflexure point has little effect on the ultimate strength for mode(c). 5)Ultimate strength of the member with contraflexure point subjected to distributed or multiple loads can be calculated on the basis of the cumulative damage by each component of shearing forces. 6)The effect of shear reinforcement in plane members varies with the arrangement of the reinforcement.

尽管到目前为止已经建造了许多地下混凝土结构，但这种结构的设计基于对地球结构的研究结果。但是，据认为，由于地球压力而受到分布载荷的地下结构比具有集中载荷的结构具有更多的盈利性能。由于地下结构通常由平面成员组成，因此希望在没有剪切钢筋的情况下获得所需的强度和延展性。此外，在结构的最终极限状态下，可以预期地球的约束作用。这项研究的目的是为地下混凝土结构剪切建立合理的设计方法。为了实现这一目的，进行了具有矛盾点和钢筋混凝土板的钢筋混凝土梁的实验。本研究中获得的主要结果如下。 1）具有矛盾点的钢筋混凝土构件的剪切故障模式可以分为三种类型；（a）单个对角线裂纹的对角线张力失败，（b）对角张力破坏两个对角线裂纹，以及（c）混凝土在连接负载点和支撑点的方向上的压缩故障。 2）可以使用相应的剪切跨度来计算故障模式的终极强度（a）。 3）模式的终极强度（b）可以计算为每个剪切范围与矛盾点的计算值的较大值。 4）矛盾点对模式的最终强度几乎没有影响。 5）可以根据剪切力的每个成分的累积损伤来计算矛盾点的最终强度。 6）平面构件中剪切钢筋的影响随钢筋的排列而异。