Asnake, Adamu (PhD)Andargachew, Mekonen2019-05-312023-11-112019-05-312023-11-112018-02-18http://etd.aau.edu.et/handle/12345678/18365Reinforced Concrete structures have been designed for long time using the Elastic and Plastic limit state theories. However, real life experiences shows that these theories are not sufficient for having the expected Failure Mode which is called Ductile Failure. In the Limit States theory, one of the major drawback is, it assumes strength as a material property independent of size. But in reality, the size effect is significant phenomena in controlling the failure mode. Limit States theory missed the concept of Size Effect. The basic concept behind the Size Effect is, as the size of the material increase, the volume of micro cracks and flaws also increase. This internal micro cracks and flaws are points where stress concentrations occurs. Through time, these micro crack and flaws will develop in to macro cracks. Therefore, the strength (Tensile and compressive) are dependent on Material member length and cross section. In this Thesis, crack propagation and section capacity for Reinforced Concrete structures are analyzed using the size effect concept which is addressed using Fracture Mechanicsen-USCrack PropagationSection Capacity calculationFracture MechanicsConcreteThesis