Abstract: Concrete slab foundation and method of construction in which ground soil is graded to form a building pad, a plurality of plastic domes having top and side walls are placed in a rectilinear array on the pad, and concrete is poured over the domes to form a monolithic structure consisting of a gridwork of criss-crossing ribs between the side walls and a horizontally extending deck above the top walls. The concrete is prestressed with longitudinally extending tendons in the ribs, and the plastic domes are left in place as a permanent part of the foundation to serve as a moisture barrier at the under side of the deck and the lateral faces of the ribs.

Abstract: A foundation for supporting a superstructure in which the foundation comprises precast concrete beams mounted on and supported by at least two non-precast pier elements. Each of the pier elements is poured in place in specially formed vertical holes in the ground at the construction site and have an axially aligned reinforcing rod which extends upward above the top of the pier. Each precast beam has at least two spaced-apart apertures which overlie the respective pier elements. In one embodiment, these apertures receive the reinforcing rods of the pier elements when the beam is mounted upon the piers during construction, and cementing material is introduced into each aperture to effect a bond between the beam and each pier element associated therewith. Each precast beam is thereby supported in an upright position with the beam parallel to the ground. In another embodiment, a tubular pedestal is affixed to the top of the pier and the reinforcing rod of the pier extends into but not above the tubular pedestal.