STUDY ON SHEAR FRACTURE MECHANISM OF REINFORCED CONCRETE MEMBERS

对钢筋混凝土构件的剪切断裂机理进行了试验和数值研究。在实验研究中，测试程序由四个系列组成。第一个系列的主要参数是轴向力水平。第二部分讨论了压区对抗剪能力的影响。预裂构件和构件在循环荷载作用下的抗剪强度问题分别作为第三和第四系列进行了研究。从这些试验研究中可以看出，轴向力对斜拉裂缝的发生和钢筋混凝土构件的抗剪强度的影响是明显的。数值分析采用退化等参异优壳单元和三维非线性实体单元的有限元方法。通过有限元分析，可以对工字梁的复杂断裂机理进行分析。并对附加加固桥墩的断裂过程进行了数值分析。本报告是根据上述研究的成果编写的。然而，在剪切断裂机制中存在一些难题，如构件受循环荷载和/或构件存在一些初始裂纹，仍有待研究。今后有必要对这些问题进行研究。

Shear fracture mechanism of reinforced concrete members are studied experimentally and numerically. In the experimental study, The test program consists of four series. The main parameter of first series is the level of axial force. In the second series, the effects of compressive zone on the shearing capacity are discussed. The problems on the precracked members and the shear strength of the member subjected to cyclic loading are studied as the third and fourth series respectively. From those experimental studies it was evident that the effects of the axial force for the occurrence of the diagonal tension cracks and the shear strength of the reinforced concrete members.For numerical analysis, the finite element approach using the degenerated isoparametoric Heterosis shell elements and the three -dimensional nonlinear solid elements were adopted. By use of the finite element analysis the complex fracture mechanism as I-shape beam can be analyzed. Also the fracture processes of the pier reinforced by additional reinforcements is analyzed numerically.The present report is composed from the fruits of above studies. However, some difficult problem in shear fracture mechanism, such as the member subjected cyclic loading and/or the member have some initial cracks, remains to be seen. It will be necessary to study on such problems in the future.