Circular Storage Tanks and Silos
Cylindrical walls of circular tanks and other containers are usually subjected to radial pressure from the
contained material or from externally retained earth. This pressure is here assumed to have an intensity that is
constant at any one level but varies in the vertical direction. Other sources of such axisymmetrical loading on
walls are circumferential prestressing, weight of overhanging circular platforms or peripheral channels.
This type of loading produces axisymmetrical radial displacement. The wall edges at the top or bottom may be
free to rotate or translate and may be restrained by the base or the cover. Thus the edges may receive
axisymmetrical radial shear or bending moment. Such end forces will also develop at a restrained edge due to
the effects of axisymmetrical temperature variation, shrinkage or creep of concrete.
For the analysis of a wall of this type it is sufficient to consider the forces and the deformations of a typical
elemental strip parallel to the cylinder axis. The radial displacement of the strip must be accompanied by hoop
forces. As will be discussed later, the elemental strip behaves as a beam on elastic foundation which receives
transverse reaction forces proportional at every point to the deflection of the beam. The analysis constitutes a
solution of one governing differential equation relating the deflection to the applied load.
The objective of this book is to provide a solution of the above-mentioned differential equation to obtain the
reactions on the edges and the internal forces in circular-cylindrical walls. For the sake of simplicity in practical
application, design tables are provided and their use illustrated by examples. While the tables are intended
mainly for use in design of concrete tanks, they can also be utilized in the analysis of silos, pipes or any
circular-cylindrical shell when subjected to axisymmetrical loading and support conditions. The tables are also
applicable for the more general problem often met in practice of a beam on elastic foundation