Numerical Investigation On Size Effect On Shear Behavior Of Reinforced Concrete Beams Without Web Reinforcement

Many scholars at home and abroad have already done a lot of research on size effect on shear behavior of reinforced concrete beams without web reinforcement at present, and it is shown that there is apparent size effect on shear capacity of reinforced concrete beams without web reinforcement. Up to now, research on size effect on shear behavior of large reinforced concrete beams without web reinforcement is rare, especially on large beams with effective depth over1000mm. On the one hand, the root of this problem is due to the limited by laboratory conditions. On the other hand, analysis on shear failure of large reinforced concrete beams without web reinforcement requires a lot of manpower and resources. Therefore, it is a good choice to use software of finite element analysis for reinforced concrete beams without web reinforcement.Finite element software DIANA was used in a finite element model based on fracture mechanics in this paper, and the nonlinear finite element was adopted to analyze the reinforced concrete beams without web reinforcement. Based on the comparative analysis with test result at home and abroad, a group of specimens with effective depth ranging from500mm to3000mm were selected for modeling in different aggregate size, shear span ratio, concrete strength, effective depth, longitudinal reinforcement ratio. As the depth increased, the extent of the impact on shear capacity of reinforced concrete beams without web reinforcement in differect factors was analyzed by numerical calculation. And shear design method in the Code for Design of Concrete Structures (GB50010-2010) for reinforced concrete members without web reinforcement was improved.It is shown that for large reinforced concrete beams without web reinforcement, the maximum aggregate size has some impact on shear capacity but not clear. Longitudinal reinforcement ratio has some impact on shear capacity, and shear capcacity has a smaller increase with longitudinal reinforcement ratio increasing. Shear span ratio, concrete strength, and effective depth on shear capacity of concrete beams without web reinforcement have a greater impact. The improved shear equation can well reflect the size effect on shear capacity of reinforced concrete beams without web reinforcement, including large beams.