Building structures are often complex, so that a large number of unknowns is required to determine the stresses and displacements in great detail. Particularly in case of unsymmetrical load such a computation becomes very complicated and expensive. In a field investigation on a silo, an efficient method to analyse unsymmetrically loaded circular cylindrical shells according to finite strip method and using mixed variables has been developed. The unsymmetrical load is developed into harmonics so that the load of each series term can be handled separately. The resulting set of equations for circular cylindrical shell is of the same form as previously derived for plane structures, allowing the same solution methods and computer programs to be used again.