Basic Structural Design of Concrete Chimneys

The paper summarizes additional problems that, at the present time, are not incorporated in the ACI Chimney Code. Besides the static wind loading, which is covered in the ACI Code, the paper outlines the effect of the radial pressure distribution and the effect of ovalling and swaying due to resonant wind conditions. The procedure and formulas for computing the model magnification factor for resonant conditions are included. The paper also treats the earthquake response problem and makes recommendations based on studies conducted on actual chimneys that were subjected to actual accelerogram records. Formulas for computing and distributing the based shear along the chimney are given. Finally, the paper emphasizes the importance of a maximum stress investigation based on a load factor times the working load moments. This is necessary because of the nonlinear variation of the stress in the vertical steel with respect to the changes in the moment.