Clarification of Out-plane Shear Resisting Mechanism of Planer Member and Design

平面构件抗平面剪力机理的阐明及设计

基本信息

批准号：
04650414
负责人：
KAKUTA Yoshio
金额：
$ 1.34万
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：
1992
资助国家：
日本
起止时间：
1992 至 1993
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-04650414/
关键词：
Reinforced concrete Slab Punching shear Axial force Shear reinforcement Continuous fiber reinforcement Finite element analysis Axis-symmetric problem

项目摘要

In this year the objectives were- evaluation of influence of shear reinforcement amount on punching shear strength- establishment of a macro model for out-plane shear resisting mechanism using nonlinear finite element analyzesThe results are summarized as follows :1 In order to clarify the influence of shear reinforcement amount, two-way slabs were tested in which shear reinforcement amount was varied from 0 to 0.34% by varying number of deformed stirrups with the same diameter. Although apunching shear strength in the case without the stirrup was understimated by the equations in CEB/FIP Model Code 90 (The equation in JSCE's Standard Specification estimated it reasonably.), increments in the punching shear strength with increase in shear reinforcement amount was estimated approximately. For the cases of small amounts of shear reinforcement (0.11 and 0.23%) the ovserved strength increments were less than the predicted ones probably because the stirrups were placed at too big spacings.2 Since variation of punching shear strength due to variation of tensile reinforcement stiffness (ratio times elastic modulus) is the same as that of shear compression strength of linear members, a new macro model was proposed applying the shear resisting model for linear members which was derived from numerical experiments with nonlinear finite element analyzes to planer members (slabs). This model consists of shear resisting of concrete in compression zone and shear resisting in shear cracking zone. It is necessary to quantify sizes and critical stresses of the two zones.Presently a constitutive model for concrete subject to tri-axial stresses is being implemented into the program of the nonlinear finite element analysis. It is mecessary to establish a macro model for shear resisting in which unclarified parameters, such as loading area configuration and shear span to depth ratio, are considered, conducting numerical and experimental analyzes.

今年的目标是——评价抗剪配筋量对冲剪强度的影响——利用非线性有限元分析建立面外抗剪机构的宏观模型，结果总结如下：1 为了明确抗剪配筋量方面，对双向板进行了测试，其中通过改变相同直径的变形箍筋数量，使抗剪配筋量从0%变化到0.34%。尽管CEB/FIP模型代码90中的方程低估了无箍筋情况下的冲剪强度（JSCE标准规范中的方程对其进行了合理估计。），但冲剪强度随抗剪配筋量的增加而增加的估计值约为。对于少量抗剪钢筋（0.11 和 0.23%）的情况，观察到的强度增量小于预测值，可能是因为箍筋放置的间距太大。2 由于抗拉钢筋刚度的变化导致冲剪强度的变化(比值乘弹性模量)与线性构件的抗剪压缩强度相同，应用平面构件非线性有限元分析数值试验推导的线性构件抗剪模型，提出了新的宏观模型（板）。该模型由受压区混凝土抗剪和剪裂区混凝土抗剪组成。有必要量化这两个区域的尺寸和临界应力。目前，承受三轴应力的混凝土本构模型正在被应用到非线性有限元分析程序中。有必要建立抗剪宏观模型，其中考虑加载区域配置和剪跨深度比等未明确的参数，进行数值和实验分析。