Study On Initial Deformation Cracks On Shear Behaviour Of R.C. Beam

The reinforced concrete structure is the non-homogeneous heterogeneous composite formed by many kinds of different materials, and it is in three-phase compatible states ( solid phase, liquid phase and gas phase) in the course of hardening. Because concrete have low tensile strength characteristics, general concrete always work with cracks, but the more important thing is how to avoid the visible macroscopical cracks, especially no cracks that influence structural security will appear. This thesis has discussed the classification of the cracks and approach of controlling the cracks at first. Later, we discuss the shear strength of reinforced concrete beams with common vertical deformation cracks. At present, the effect of initial deformation cracks on the shear strength of reinforced concrete beams has researched very little, so we carry on further research on this.In the arithmetical theory, we analyze the performance of shear strength and rigidity of reinforced concrete beams with vertical deformation cracks using ANSYS finite element software. We have two simulation ways to simulate bonding performance of cracks. One is killing the concrete elements and the other is reducing the strength of concrete where there are cracks.1. In the situation of killing the concrete elements, we analyze the shear strength and rigidity of reinforced concrete beams without cracks, with different crack width, the number of cracks. Crack has great influence on performance of beams. Crack width has very little impact without considering the bonding performance of cracks. The number of cracks has great influence on performance of beams and the beams have a greater shear strength reduction with one crack.2. In the situation of reducing the strength of concrete where there are cracks, we compare the shear strength and rigidity of beams with different strength of concrete where there are cracks and get the relationship between shear strength of concrete beams and strength of concrete where there are cracks. This offers reference for further studying on bonding performance. In addition, we have also carried on the discussion to relevant knowledge and questions met in the ANSYS finite element modeling and calculation of finite element.At last, we analyze the shear strength and rigidity of reinforced concrete beams without cracks, with different crack width and the ways of simulation( using plastic with hole and iron sheet to separate) through experiment. Through comparing the data of experiment and theory, it has proved that analyzing shear strength of R.C. beams with ANSYS software is feasible.