Abstract: A method and apparatus for retensioning the development length of strands of an elongated prestressed concrete member is provided in which the ends of the strands are exposed, a metallic plate having tapered holes therein is placed over the ends of the strands, retaining wedges are inserted into the tapered holes of the plate to grip the ends of the strands, and a predetermined amount of tension is applied to the strand and maintained in the strand by the retaining wedges. A jack is provided to apply the tension to the strand. The prestressed concrete members such as piling, may be spliced together by using the apparatus on adjoining ends of piling.

Abstract: A new pile is disclosed which includes a pile shaft and wedge-forming means of castable material spaced upward of the tip of the pile shaft and proximate thereto. The wedge-forming means cooperates with the portion of the pile beneath it, during driving, to cause the formation of a wedge of soil. The thus-formed soil wedge is in contact with other soil and the resulting soil-soil interface has enhanced pile supporting characteristics.

Abstract: A drive fit coupling for joining together a pair of plain end concrete piles each having a polygonal cross sectional configuration is disclosed. A metal sleeve is provided in which a portion of the perimeter of the sleeve wall expands outwardly as the piles are driven into the sleeve causing the sleeve to fit tightly over the ends of the piles. The friction of the sleeve around the pile ends is sufficient to resist bending thereby keeping the joined piles straight during driving. Center stopping means is also provided to prevent a pile from entering the sleeve beyond the vertical center thereof.

Abstract: The present invention relates to elongated elements of concrete pre-stressed by tensioned reinforcements adherent to this concrete. Each element comprises a box capping its end to which the reinforcements are fixed and which is provided with a flange allowing tensioning of the reinforcements and the possible assembly of two elements end to end. The invention is applicable to all structures formed by elements pre-stressed by adherent reinforcements, and in particular to driven-in piles.

Abstract: An element for use in concrete pile casting to align coupling members on end fittings during the pile casting operation. The end fittings have key grooves, each such groove designed, when two concrete pile sections are to be joined together, to receive therein a locking key to interconnect the end fitting at one of the ends of a concrete pile section with a matching end fitting at the opposed end of the other pile section. At the bottom of each key groove is formed a through-passage with a recessed seat therein to accommodate the coupling member which rests freely in the seat and which is coupled to a reinforcement iron rod extending lengthwise through the concrete pile.The aligning element comprises a presser means extending through a support member which is placed in one of the key grooves. The presser means is arranged to be pressed against the free end of the coupling member while the side faces of the key groove serve as back-up faces to said support member.

Abstract: The invention relates to an extension joint for concrete poles of the type in which at least one pin in a first pole penetrates into a recess in a second pole. The end of the pin is provided with a shoulder and is locked in the second pole by means of a wedge having shanks each engaging one side of the pin. The wedge is locked in its driven-in position while being driven in by the bending of the shanks towards each other after they have passed the pin. The wedge and the free end of the pin are covered by a channel member or furrow, whose side walls have portions bent inwards and guiding the shanks when the wedge is being driven in.

Abstract: A new pile is disclosed which includes a pile shaft and wedge-forming means of castable material spaced upward of the tip of the pile shaft and proximate thereto. The wedge-forming means cooperates with the portion of the pile beneath it, during driving, to cause the formation of a wedge of soil. The thus-formed soil wedge is in contact with other soil and the resulting soil-soil interface has enhanced pile supporting characteristics.

Abstract: The disclosure teaches a structure enabling a reinforced concrete pile to be placed in tension. The disclosure illustrates the usual in-service environment of two piles after being coupled in the field and capable of being stressed in tension. Shear pins distribute the tensile load to cast-in-place anchor members. Only that portion of the compression necessary for understanding is illustrated, although the novel features enhance conventional compression capabilities. The foregoing abstract is merely a resume of one general application, is not a complete discussion of all principles of operation or applications and is not to be construed as a limitation on the scope of the claimed subject matter.

Abstract: The method aspect of the invention comprises stabilizing an earth structure by forming a plurality of concentric boreholes therein, and inserting, in each of the boreholes, a friction rock stabilizer. A friction rock stabilizer, so defined as to be useful in the method, comprises another aspect of the invention, the stabilizer having a plurality of concentric, tubular bodies. In this novel friction rock stabilizer, one of the tubular bodies defines an axial extension of another thereof. In addition, then, the invention further embraces the definition of a novel axial extension for a friction rock stabilizer.

Abstract: A reinforced concrete threaded pile provides a generally conically shaped tapered concrete pile member which is provided with a metallic reinforcement core for carrying the torsional and tensile forces created in the pile during its insertion. A metallic head is provided at, for example, the upper portion of the pile, which provides a point for the connection of a sufficient torsional driving force thereto for insertion of the pile. The head member can be metallic, and is substantially integrally connected to the reinforcement core, so that the torsional forces can be developed through the head and the reinforcement core such that torsional and tensile forces are not carried by the concrete to a degree which would cause a failure of the concrete by cracking. The concrete body is provided with an outer surface of spiral threads which has a relatively minor thread pitch that provides for relatively easy insertion of the pile into the desired soil medium and is mechanically compatible therewith.

Abstract: The invention is concerned with a method of driving a columnar pile into the ground. The pile is formed by a number of load-bearing segments each of which contributes only a part of the area of contact between the surface of the pile and the surrounding earth. The load-bearing segments at any time forming that part of the pile in the ground are advanced in turn a little way into the ground and the cycle is repeated over and over again until the pile is in its fully driven position.

Abstract: An improved joint for pile sections which have a nut at the ends, fastened such that one of its end surfaces is in the same plane as the end surface of the pile section. The joint being effected by a threaded bolt which engages with the nuts on two cooperating pile sections. The nut is provided with an annular groove having radially-directed locking notches in the bottom. A locking disk is inserted into the groove. The disk has resilient locking tongues with radial edges which are directed against the unscrewing direction and which engage with the notches in the nut.

Abstract: A process for building-up a pre-formed concrete piling while the piling is in place in terrain to form a finished piling foundation of uniform height above reference terrain level having a pre-formed portion and a cast-in-place portion.