Differential Settlements in Steel Tanks

Abstract

Case histories of tank settlement and damage are examined to determine which factors control the magnitude of differential settlements of tanks. The available data are used to assess the accuracy of conventional settlement analysis procedures as applied to steel tanks on compressible foundation soils and to determine the magnitudes of differential settlement that tanks can tolerate without damage. New criteria for tolerable settlements of tanks are recommended. These new criteria apply to the three settlement profile shapes found to develop in actual tanks. The new criteria are easier to apply than some of the criteria proposed previously, because they do not require determination of the distance from the tank edge to the point of maximum settlement, a quantity that cannot be calculated using any simple analytical procedure. The influence of this distance, important in determining the distortion of the tank bottom, is incorporated in the new criteria through use of different magnitudes of tolerable settlement depending on the shape of the settlement profile.