An improved method of tensioning and anchoring wires

751,631. Wire tensioning and anchoring. CONCRETE PATENTS, Ltd. Feb. 23, 1954, No. 5355/54. Class 45. [Also in Group X] A method of compressing a concrete structural element 4 by tensioning a wire 2 disposed within a cavity 3 comprises initially disposing the wire so that a shoulder 5 is within the cavity, placing a nut 12 about the wire, applying tension to the wire to bring the shoulder outside the cavity, disposing about the wire between the shoulder and the element at least two blocks 10, 11 forming part of a threaded cylinder, screwing the nut on the block combination until it bears against the shoulder, and releasing the tension so that the element is compressed by the residual tension in the wire. The wire has a head 8 engaged by the jaws 9 of a jack 7 during the tensioning. The shoulder and head are formed by cold working. Two or more wires may be used by forming the threaded cylinder of three or more blocks.