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研究和数值模拟。在实验研究中，测试方案包括四个系列。第一系列的主要参数是轴力水平。在第二系列中，讨论了受压区对受剪承载力的影响。第三、四系列分别研究了预裂构件和循环荷载作用下构件的抗剪强度问题。试验研究表明，轴力对斜拉裂缝的产生和钢筋混凝土构件的抗剪强度有明显的影响。数值分析采用退化等参杂交壳单元和三维非线性实体单元。利用有限元分析可以分析工字形梁的复杂断裂机理。本文综合以上研究成果，对附加钢筋加固桥墩的断裂过程进行了数值分析。然而，在剪切断裂机理方面的一些难题，如反复荷载作用下的构件和/或构件中存在初始裂纹等，还有待进一步研究。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.