Lightweight, screw anchor supported foundation and method of installing

Abstract

A lightweight, easily installable, anchored foundation for electrical equipment or the like is provided which includes a foam-filled, force-transmitting frusto-conical housing tensionably connected to a plurality of adjacent, buried earth anchors having remote load-bearing helices thereon in order to create a prestressed bulb of relatively compacted soil between the housing base and anchor helices which greatly enhances the holding power of the foundation under both tension and compression loads. In preferred forms the foundation exhibits approximately the same support strength as poured concrete, but can be more quickly installed and employed at remote locations or on loose soil which would normally preclude the use of concrete. In preferred forms, the housing is substantially buried and external foam fill is deposited about the base of the housing to absorb any transverse loads, and force-transmitting internal housing ribs are provided which serve to transmit tension forces from the earth anchors to the supported structure. An installation method is also disclosed which includes positioning the housing within an augered hole proximal to embedded earth anchors, attaching the latter to the housing in a manner to tensionably pull the housing base and anchor helices in opposition to each other for creation of a compacted soil bulb, foam filling the housing and the exterior volume adjacent the base thereof, and refilling the hole with earth to substantially bury the foundation.