Review article

Flexural rigidity of the reinforced rod depends upon the load level so that long before fracture the rod of constant cross section turns into the rod with variable rigidity. This feature is required to be taken into account. The present paper is the first part of the study on the problem of reinforced beam column analysis. It proposes a sufficiently simple formula for rod’s bending rigidity. This formula uses no empirical coefficients, it takes into account micro cracking, elastic-plastic behavior of compressed concrete and the presence of longitudinal compression.