Abstract: A hollow mandrel has a chute at one side near its top through which concrete is poured, and an open top through which re-inforcing steel is inserted. An expansible closure having an air conduit leading to its lower end is lowered into the mandrel below the chute and expanded, and air is forced into the mandrel while a lifting force is applied to it.

Abstract: A pile driving rig is used to pre-drill a hole into which an elongate element, such as a pile or a hollow mandrel is inserted. A large portion of the weight of the rig is imposed upon the elongate element by a jack system, one part of which rests upon the pile element and the other part of which jacks up one end of the rig. If further seating of the pile is desired the jacking force is momentarily released so as to drop the superimposed weight of the rig onto the elongate element.

Abstract: A pile is lofted to a vertical position over a driving location. At a distance above its lower end the pile is embraced within a guide on an extensible rack on the crane chasis. Over the upper end of the pile a vertically elongate socket on the lower end of a hammer carriage is fitted, and driving ensues until the pile is self-sustaining, or until the hammer carriage nears the rack. Then the rack is disengaged from the pile and withdrawn, and driving is completed.

Abstract: After wet-drilling a hole until a bearing strata is reached, a mandrel with a removable overboot is lowered into the hole and the overboot is seated by a few hammer blows. The mandrel is then partly filled with thick concrete from its top, the top of the mandrel sealed, air-pressurized and a mechanical lifting force is applied. The pressure of the air within the mandrel plus the weight of the concrete forces off the overboot, and also forces the thick concrete against the sides of the hole, and the concrete forms a seal between the sides of the hole and the mandrel. The air pressure also helps lift the mandrel out of the hole.

Abstract: After wet-drilling a hole until a bearing strata is reached, a mandrel with a removable overboot is lowered into the hole and the overboot is seated by a few hammer blows. The mandrel is than partly filled with thick concrete from its top, the top of the mandrel sealed, air-pressurized and a mechanical lifting force is applied. The pressure of the air within the mandrel plus the weight of the concrete forces off the overboot, and also forces the thick concrete against the sides of the hole, and the concrete forms a seal between the sides of the hole and the mandrel. The air pressure also helps lift the mandrel out of the hole.

Abstract: After a hole has been wet-drilled with mud left in, a hollow mandrel with an inflatable bladder is inserted into the bottom of the hole. The bladder is inflated so as to seal against the sides of the hole and concrete is pumped into the hole below the bladder seal to force the mandrel with the inflated bladder thereon upwardly through the hole.

Abstract: Vertically disposed plates extending across the interior of a partly driven hollow pile shell near the top thereof have outer ends extending through slots in the shell wall, which outer ends are welded to the outer side of the shell wall. The bottom edge of the next succeeding shell is butt welded to the top edge of the lower shell, the two shells are inserted into a drilled hole and driven to a light blow count, and a mandrel is then inserted through the next succeeding shell until it engages against the plates, and the composite pile is driven home to the desired blow count.