Abstract: An upright cylindrical pier foundation is constructed of cementitious material. The lower end of the foundation has a plate or circumferential ring fully embedded therein and long circumferentially spaced rods or bolts have their lower ends anchored relative to the ring. The upper ends of the long rods project up outwardly of the top of the foundation. The rods are shielded over substantially their entire length against bonding with the cementitious material to allow the rods, when heavily tensioned, to stretch within the cementitious material. A heavy flange, which may comprise the base flange of a tubular tower, is positioned downwardly upon the upper end of the foundation with the upper ends of the bolts projecting through holes provided therefor in the base flange.

Abstract: A hollow, cylindrical pier foundation is constructed of cementitious material poured in situ between inner and outer cylindrical corrugated metal pipe shells. The foundation is formed within a ground pit and externally and internally back filled. The lower end of the foundation has a circumferential ring fully embedded therein and sets of inner and outer circumferentially spaced bolts have their lower ends anchored to the anchor ring, their upper ends projecting up outwardly of the top of the foundation and a majority of the midportions thereof free of connection with the cementitious material of which the foundation is constructed. The base flange of a tubular tower is positioned downwardly upon the upper end of the foundation with the upper ends of the inner and outer sets of bolts projecting upwardly through holes provided therefor in the base flange and nuts are threaded downwardly upon the upper ends of the bolts and against the base flange.