GB608593A - Reinforcement for prestressing and reinforcing concrete constructions - Google Patents

Abstract

608,593. Reinforcements for concrete. SOC. DES GRANDS TRAVAUX DE MARSEILLE. April 4, 1945, Nos. 8367 and 8368. Convention dates, Sept. 30, 1943 and May 12 1944. [Class 20(iv)] A prestressed reinforcement for concrete comprises a sheath under tension and a core, which is ultimately removable, under compression, the ends of the sheath and core being locked together whilst the concrete is setting, and is characterized by the reinforcement being readily bent into a desired configuration. The sheath may consist of parallel wires 1, of any desired section, held together by spaced hoops 3 or by a coiled wire, and the core 2 may be a continuous rod, with or without hoops, or it may be a close packed, helical squaresectioned wire spring. The wires 1 are locked at each end in a head 4 of metal or hooped concrete, hooks 5 being embedded in the head so that tension may be applied to the wires 1 by a jack which reacts on and compresses the core 2. The sheath and core are maintained in stressed condition by a key bolt 6 which is inserted before the removal of the jack, and is knocked out after the concrete has set. In Figs. 5, 6, the core consists of parts 18 shaped to permit bending of the sheath, and kept together by balloon springs 19<1>. The sheath consists of twisted and braided wire 12 and the ends of the sheath are sealed in a fusible material 16 in the space between an outer sleeve 14 and an inner tapered sleeve 15. The stresses are applied to the core and the sheath by a jack which acts between the inner end of the. sleeve 14 and the end of a push rod 10 which bears on the core. After tension is applied to the sheath, the nut 21 is screwed into contact with the rod 10 and the jack is removed. The tensions are released when the concrete has set, by melting the material 16 by an electric heater 22. According to the e Specification as open to inspection under Sect. 91, the core may consist of hard metallic pellets or a bundle of hard parallel. wires. This subject-matter does not appear in the Specification as accepted.