Method and apparatus for post-tensioning segmented concrete pilings

A cable anchor adapted to be located at the bottom of a foundation piling having a plurality of piling segments, each having an aligned hole for receiving a cable, comprising:

• a plurality of lock members, each having an outer wall and a partially cylindrical recess formed on an inner wall, the lock members being arranged around a longitudinal axis of the cable anchor so that the recesses combine to define an axially extending lock member passage for receiving an end of the cable;
• and
• a cam surface that mates with the lock members so that axial movement of the lock members and the cam surface in a first direction causes the lock member passage to expand to receive an end of the cable, and axial movement of the lock members and the cam surface in a second direction causes the lock member passage to constrict to grip the end of the cable to post-tension the piling;
• a cylinder having a bore;
• an insert located within the bore of the cylinder, the insert having an axially extending insert passage for receiving an end of the cable, the insert having a downward facing conical bore section that joins the insert passage and serves as the cam surface;
• wherein the outer walls of the lock members slidingly engage the conical bore section;
• and
• an elastomeric member located below the lock members and having an upper surface that urges the lock members upward in the second direction relative to the conical bore section.

A cable anchor adapted to be located at the bottom of a foundation piling having a plurality of piling segments, each having an aligned hole for receiving a cable, comprising:

• a downward facing conical surface;
• a plurality of lock members, each having an outer wall slidingly mating with the conical surface and a partially cylindrical recess formed on an inner wall, the lock members being arranged around a longitudinal axis of the cable anchor so that the recesses combine to define an axially extending lock member passage for receiving an end of the cable;
• a plurality of teeth formed on the recesses for gripping the cable;
• and
• a resilient member engaging a lower side of the lock members for urging the lock members upward relative to the conical surface to reduce a diameter of the lock member passage for gripping the cable, the resilient member allowing downward movement of the lock members relative to the conical surface to expand the diameter of the lock member passage for receiving an end of the cable as it is lowered through the piling segments into the cable anchor.