The paper presents the ring sectionmodel for nonlinear analysis of the resistance of RC chimneys, assuming the nonlinear stress-strain relationship for concrete in compression according to Eurocode 2. The cross-sectional resistances are derived in the analytical form by integrating the equilibrium equations and taking into account the geometrical and physical relationships. The calculated results are presented in the form of interaction diagrams and compared with those based on the parabolic- -rectangular diagram for concrete in compression. Keywords: section model; resistance; chimney; reinforced .