In the past few years, great strides have been made toward simplification and improvement of the classical methods of the design of circular tanks. The need for a fast and efficient method by which engineers may determine the "indeterminate" stresses that exist in the walls and floors of circular tanks, of steel and concrete, has long been recognized. A simplified approach to the problem, which has been used by engineers for many years, merely employs the basic history of liquid pressure on the walls of pipes of large diameter. However, the use of this theory results in great waste of structural material. The advent of modern methods of placing reinforce concrete and the use of large, shallow settling tanks, has necessitated a more thorough investigation of the stress distribution both in tension and in bending, which exists in the tank wall, through the continuity between floor and wall. Credit for the introduction of a more rigorous analysis of the stresses in circular concrete tanks may be given to Mr. George S. Salter (1), whose theory has become quite popular since 1940, although the U.S. Navy (2) published charts and tables of tank stress distribution as early as 1924. A few existing theories will be discussed in Section II. Although there have been very few failures of tank structures, a more thorough study of tank design is still needed by the engineering profession. It is hoped that this thesis may, to some extent, contribute to forming a basis for future improvement and simplification of the popular methods of tank design. / Master of Science