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Effect of Cyclic Loading upon Shear Behavior in Fracture Process Zone of Concrete

循环荷载对混凝土断裂过程区剪切行为的影响

基本信息

批准号：
12650566
负责人：
SHINOHARA Yasuji
金额：
$ 2.11万
依托单位：
Tokyo Institute of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2000
资助国家：
日本
起止时间：
2000 至 2001
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-12650566/
关键词：
Concrete Fracture Process Zone Cyclic Shear Response Shear Retention Factor Crack Width Shear Displacement Confining Pressure Servo System 破戒進行領域ひび割れ荷重制御変位制御

项目摘要

The primary purpose of this experimental investigation is to obtain the cyclic shear response in a fracture process zone that the stress can still be transferred in spite of the damage, and to accumulate the necessary information that applies to nonlinear finite element analysis. Since the mixed mode loading in concrete structures is a consequence of the presence of a crack due to principal tensile stresses and subsequent rotation of the principal stress direction, testing methods require that a small crack can be generated first under pure tension and that shear can be applied in a second stage. For that reason, a biaxial testing device, with which the vertical and horizontal load as well as displacement can be independently controlled by closed-loop servo systems, has been developed in order to establish the cyclic shear behavior in cracked concrete. In this experiment, the cyclic shear tests on specimens containing narrow cracks introduced by the tensile test in displacement control … More have been mainly carried out under the boundary conditions maintaining either normal displacement or load across the crack surface constant. However, in reinforced concrete structures, this loading path will never occur because any increasing of crack width causes an increase of tensile force in reinforcement crossing the crack planes and subsequently makes the confining pressures increase simultaneously. Therefore, the shear tests have been also carried out to study the effect of confining pressures across the crack surface. Unlike others, the confining pressure is all the time estimated by crack width, reinforcement ratio, constraint length relating to the slip between concrete and reinforcement, yield strength of reinforcement and automatically applied on the crack surfaces by closed-loop servo systems. The relation of normal and shear loads to crack opening and sliding displacements was discussed on the basis of the various boundary conditions of the normal direction across the crack surface. Less

本实验研究的主要目的是获得在断裂过程区的循环剪切响应，应力仍然可以传递，尽管损坏，并积累必要的信息，适用于非线性有限元分析。由于混凝土结构中的混合模式加载是由于主拉应力和主应力方向的随后旋转而导致的裂缝的存在的结果，因此测试方法要求可以在纯拉伸下首先产生小裂缝，并且可以在第二阶段施加剪切。为此，双轴试验装置，其中的垂直和水平荷载以及位移可以独立控制的闭环伺服系统，已被开发，以建立在开裂混凝土的循环剪切性能。本试验采用位移控制的拉伸试验，对含窄缝试件进行循环剪切试验， ...更多信息主要是在保持裂纹面法向位移或载荷不变的边界条件下进行的。然而，在钢筋混凝土结构中，这种加载路径将永远不会发生，因为裂缝宽度的任何增加都会导致穿过裂缝平面的钢筋中的拉力增加，从而使围压同时增加。因此，还进行了剪切试验，以研究围压对裂纹面的影响。与其他方法不同的是，围压始终由裂缝宽度、配筋率、与混凝土和钢筋之间的滑移有关的约束长度、钢筋的屈服强度来估计，并通过闭环伺服系统自动施加在裂缝表面上。根据裂纹面法线方向的各种边界条件，讨论了法向载荷和剪切载荷与裂纹张开度和滑移量的关系。少