Study on Type II Shear Failure Mechanism of Reinforced Concrete

正如建议书中所提到的，本研究旨在弄清钢筋混凝土结构在剪切型破坏(我们称之为第二类剪切破坏模式)下的峰后行为和破坏阶段的破坏速度。第一步是开发计算机程序，可以捕捉到峰后阶段的剪切破坏模式。虽然在处理切向状态下本构方程的复杂性和处理加筋材料及其合并以求出屈曲张量的临界状态方面遇到了许多困难，但我们成功地开发了二维有限元程序。在第二阶段，我们开发了用于墙型结构剪切破坏试验的试验装置。由于所有的机器部件都是由研究人员设计的，所以它以相对较低的成本完成了。它现在被安装在山梨大学混凝土实验室，该实验室分享了该项目的实验部分。该试验机的特点是既能保持结构试件较长顶缘线的水平方向，又能对试件施加水平荷载和竖向荷载。利用该装置，我们成功地给出了理论所预期的正交加筋墙体试件的第二类剪切破坏模式，这意味着我们成功地对其他结构构件的第二类剪切破坏模式进行了更一般的估计。在这方面，我们以类似于冲击失效预测的方式发展了理论公式。所有这些研究成果都被公布或将被公布在同一文件中。

As has been mentioned in the proposal document, this research aimed at the clarifying the post peak behavior of reinforced concrete structural failure in the shear mode (we call this type of failure as the shear failure mode of the second type) and the failure velocity in the failing stage. The first step was to develop computer programs which can catch the shear failure mode in the post peak stages. Though we have encountered many difficulties in dealing with the complexity of constitutive equations in the tangential state and the treatment of reinforcing materials and its amalgamation to find out the critical state of acrostic tensor, we have succeeded in developing the 2D finite element programs.In the second stage, we have developed the testing apparatus to perform the shear failure tests of wall type structures. Since all the machine parts are designed by the researcher, it was completed with relatively low expenditure. It was now installed in the Yamanashi University, concrete laboratory, which shared the project in the experimental portion. The testing machine has the special feature that it can maintain the horizontally of rather long top edge line of structural specimens while giving horizontal load as well as vertical load to specimens. Using the apparatus, we have succeeded to give rise to the shear failure mode of second type for the orthogonally reinforced wall specimen as anticipated by the theory.This means that we have succeeded to estimate the failure mode of this type for other structural elements more generally.For the second aim of this project was to clarify the failure velocity of shear failure. In this regards, we have developed the theoretical formulation in the similar way as shock failure prediction.All these research results are published or to be published as listed in the same document.