Influence of Longitudinal Reinforcement on Development of Normal Cracks

Using a model of normal crack propagation in reinforced concrete members, an analytical expression is presented for the stress intensity factor defining the intensity of stress in area at the crack tip. This factor is in linear relationship to the stress in tensile reinforcement, which can be determined by different methods. The analysis performed indicates that there is a direct relationship between the stress intensity factor and normal crack depth, when a stable and chaotic propagation of cracks in the initial cracking stage of the member terminates. In addition, expression of this relationship depends significantly on reinforcement ratio of underreinforced beams.