Abstract: A circular base form is constructed from curved lengths of corugated steel bolted together and has apertured vertical brackets secured to the inside of the base form at spaced intervals around the inside of the form. Vertical anchor pins slide within the apertures of the brackets and are driven into the ground once the circular base form is positioned correctly. The upper edge of the base form is outwardly flanged horizontally and is successively leveled by transit or the like. As the sections are leveled, they are secured to the ground engaged anchor pins by ring bolts or the like until the entire form is leveled. Gravel and concrete is then poured into the form, preferably with reinforcing bars, mesh or the like and leveled flush with the top flange by means of screeding. When set, the lowermost wall section, the roof and then succeeding sections of the bin are assembled on the top flange of the base and are raised when each section is completed be means of a crane, hoist or the like.