In current economic trends, changes in construction using are required. It usually leads to changes in value and type of the working load on building structures, with the requirement to rate the technical state and replace or strengthen the elements. An important aspect of determining the residual bearing capacity of damaged bending reinforced concrete elements is the research concerning the influence of difference defects and damages on the change of strength and deformability. In the article main types of damages and defects, methods of studies of damaged reinforced concrete elements and the expediency of usage of this elements are described. However, most methods are suitable only for certain defects and damages due to the large complexity of calculations and the consideration of multifactoriality. Significant complexity of a single method for calculating damaged elements depends on the possible changing stress strain state of an element in combination with certain defects and damages, the presence of a non-complete separation where during loading or alteration of the damaged element the fractions become included in the work, reinforced concrete is the composite material which carrying complexity in calculating the joint work of its components.