GB690981A - Improved method for exerting and maintaining a tensile force on metal wires - Google Patents

Abstract

690,981. Reinforced concrete. BLATON, A.,and BLATON, E. Nov. 4, 1946 [March 21, 1942; Nov. 10, 1942], Nos. 32722/46 and 32723/46. Class 20(iv) [Also in Group I] An assembly of wires, e.g. for reinforcing concrete, is tensioned and enclosed by arranging the wires throughout most of their length in parallel spaced layers by means of separating members situated between the ends of the wires, anchoring the wires near one end, tensioning the wires individually or in pairs, and anchoring them at the other end. Fig. 4 shows an anchoring member 4 of the form described in Specification 691,023 and comprising superposed metal plates 6 and sheets 10 between which steel wires 1 are secured and distributed and from which they pass through a pyramidal envelope 2, Fig. 1, having a metal ring 3, into concrete to be reinforced. The wires are tensioned two at a time by a jack 17 supported on a base 20 bearing against the member 4 by means of stays 22. The tensioning force is exerted on a cross-piece 14 coupled by rods 13 to a cross-piece 11 having recesses 12 into one of which a pair of wires is temporarily wedged. After the wires have been tensioned they are wedged in a trapezoidal recess 7 in one of the plates 6. The jack can be vertically adjusted, for tensioning the different layers of wires, by means of pins 29 co-acting with vertically spaced apertures 28 in the base 20. The tensile force produced by the jack may be measured by a dynamometer or manometer. In a modification the wires are tensioned one at a time and each wedged in a different recess in a member 4. Other anchoring members may be used, e.g. a plate 41, Fig. 10, having flattened tubes 42 in which the wires are wedged in pairs. Simpler anchors are described, e.g. associated with a reinforced concrete beam, having one recess only in which four wires are secured in spaced relation. The wireseparating members may be pins 87, Fig. 19, or metal guide plates 88, Fig. 23, which are. surrounded by a protective sheath for the wires. The spacing of the wires facilitates their protection from corrosion by the injection of a liquid through tubes 79 or 85, Fig. 19, at spaced points, the tubes extending through the protective sheath. To ensure a good distribution of the liquid, the wires may be vibrated, e.g. by a rod 86 which may act on an anchoring member like that shown in Fig. 4. The invention is described also as applied to anchoring, quay walls, sheet piling &c. (see Group I).