GB393576A - Improvements in process and apparatus for manufacturing pieces of reinforced concrete - Google Patents

Abstract

393,576. Moulding reinforced concrete. FREYSSINET, E., 32, Rue St-James, Neuilly-sur-Seine, France. Nov. 26, 1931, No. 32805. Convention date, Nov. 27, 1930. [Class 87 (ii).] Relates to the processes and apparatus for reinforcing concrete described in Specifications 338,864, 338,934, [both in Class 87 (ii), Moulding plastic &c. substances], and 364,621, and consists in that the high tensile steel reinforcing members are (a) of unequal length and/or (b) are arranged unsymmetrically with respect to the neutral axis of the work, and/or (c) are subjected to differing initial tensions. The process is described as applied (1) to the production of a tapered post, Fig. 1 (wherein reinforcements 1 of differing lengths are employed), (2) to the production of a beam, Fig. 2, (wherein reinforcements 4 of differing lengths and asymmetrical distribution are employed. Various devices for gripping and tensioning the reinforcements are described. Posts 30, Fig. 5, may be passed into the mould, the reinforcements 33 secured by wedges engaging in slots in the upper ends of the posts 30 and tension applied by screw gear 37a. A two-part mould 35a, 35b, Fig. 9, may be employed, bosses 40 being welded thereon to receive gripping members 44 which may be of high tensile tempered chromium steel and which are clamped by screws 46. Blocks 50, Fig. 8a, may be interposed so that one pair of clamping members may grip several reinforcements. When reinforcements are tensioned to differing initial tensions, they may.be fed from a supply 60, Fig. 10, and gripped at 61 at one end of a mould 35, a second gripping member 62 being applied to the reinforcement outside the mould so that a predetermined tension may be applied as by a hanging weight F<2>. The mould is then moved in the direction Fl as by an hydraulic jack till the weights or other loading devices on the various reinforcements are operative, whereupon gripping members 66 within the mould are clamped on to the reinforcements, the mould then being returned and the reinforcements severed outside the mould. Concrete is then cast round the tensioned reinforcements. Provision is made for transferring the tension from the various reinforcements to the set and hardened concrete simultaneously. Concrete may be cast centrifugally into open-topped moulds 102, Fig. 20, which are placed around reinforcements previously embedded in concrete end blocks 101, the reinforcements being tensioned by wedges 103 driven between the mould and one of the pre-cast end blocks. The moulds are then placed in a cylinder with their open tops facing radially inwards and the concrete cast centrifugally. Specification 366,544 also is referred to.