According to the Russian building codes, the numerical study of structures should be carried out taking into account the existing defects and damages. On the example of a U-shaped reinforced concrete frame containing damage, a comparative analysis of three cases of stress-strain state was carried out in comparison with the design scheme without damage. Also, a library of typical damages of reinforced concrete columns and proposed design models was compiled. The calculations were performed by the finite element method in LIRA-SAPR.