Study on failure mechanism of reinforced concrete beam based on cohesive zone model

Abstract

The problem of crack propagation in reinforced concrete beams is common in practical engineering. It is very important to correctly describe the law of crack propagation, the mechanism of fracture failure and the internal stress and deformation characteristics of the beams. Based on cohesive zone mode, the mechanical mechanism of fracture failure of 3D reinforced concrete beams under external load is studied in this paper. By comparing the numerical simulation with the experimental results of the reinforced concrete beam, the crack distribution, expansion law and failure mode of the reinforced concrete beam under the conditions of different reinforcement ratio and spiral stirrup inclination angle are investigated. The results show that: ①a small amount of reinforcement and a superfluous amount of reinforcement will make the reinforced concrete beam show the characteristics of brittle failure, while the moderate reinforcement ratio can give full play to the ductility of the reinforced concrete beam, which is easier to bear the load of the beam; ②when the inclination angle of spiral stirrup is about 80°, the bearing capacity of normal section and oblique section of the beam reach the maximum value.

Keywords

• reinforced concrete beam
• cohesive zone model
• reinforcement ratio
• spiral stirrup
• crack expansion