A simplified method for flexural capacity assessment of circular RC cross-sections

A simplified method for the assessment of bending moment resistance for reinforced concrete (RC) members with circular cross-sections is presented. In the proposed method longitudinal rebars arrangement is replaced with a thin steel ring equivalent to the steel total area; moreover, according to modern codes, simplified stress–strain relationships for concrete and reinforcing steel are used. The performed analyses demonstrate that the value of flexural capacity determined by the proposed approach, is very close to the results obtained by applying rigorous methods based on analytical and numerical algorithms. The study also proves that in members subjected to bending moment without axial load, the flexural strength depends on the geometry of the section (i.e. radius and concrete cover) and on mechanical ratio of steel reinforcement by a very simple formula.