David L. Federer
Engineering at Peachtree Industrial Blvd, Atlanta, GA

4618289, Oct 21, 1986

May 22, 1984

6/599727

David L. Federer - Dunwoody GA

E02D 534

405236

Method for making an elongated support column extending downwardly into the ground which may be used in the construction of foundation piling, tension anchors and related installations, the method comprising generally the steps of providing a rigid elongated hollow driving mandrel with radial apertures in the lower section and having a driving foot on its lower end; passing the driving foot through and displacing the ground to form a space with a cross-sectional area greater than the mandrel in the wake of the driving foot until the uppermost radial apertures in the driving mandrel are below the level of the ground; continuing the driving of the driving mandrel and foot by introducing liquified fill material under pressure into the hollow portion of the mandrel, the pressure being adjusted so as to fill the space between the mandrel and the walls of the hole so as to prevent the ground from collapsing upon the mandrel; allowing the liquified fill material to solidify when the desired depth has been reached. The driving foot of the mandrel in all cases is left within the hole and in some instances the driving mandrel is releasably coupled with the driving foot and removed before the liquified fill material solidifies, depending on the type of structure being built.