Abstract: The calculation of the bending load of the normal section for the common reinforced concrete component which has a ring-shaped cross-section and is evenly disposd with reinforcing bars along its periphery,involves solving the equation with triangular functions. Generally, the iteration method is used for this and therefore the calculation is very combersome. In this paper, a sectional quadra-tic approximation method is proposed which is fast, simple to use and with very high accuracy.