GB636174A - A process for manufacturing pre-stressed reinforced concrete members - Google Patents

Abstract

636,174. Pre-stressed reinforced concrete. FREYSSINET, E. Feb. 5, 1946, No. 3632. Convention date, May 15, 1945. [Class 20 (iv)] In a pre-stressed re-inforced concrete member, before the main body of the concrete is cast, the main re-inforcements are stretched and anchored in members which are pre-compressed by pre-tensioned transverse auxiliary re-inforcements. The main reinforcements may be anchored in transversely prestressed concrete masses or, as shown in Figs. 2, 4, 6, between pre-formed elements which form the ends of sleepers made simultaneously in a line on a long work bench. Twelve tensioned main wire re-inforcements 1-3, 1<SP>1</SP>-3<SP>1</SP> and 11-13 (other three not shown) are placed between hardened concrete press heads 4, 41 connected by auxiliary loop wire re-inforcements 5 which also pass through intermediate additionally re-inforced concrete elements 6, 61. The main reinforcements are anchored by driving concrete wedges 7, 71, 711 between the elements 4 and 6 &c. The wedges at the ends of adjacent sleepers may be driven in simultaneously (Fig. 6) inserted rubber or steel parts 8 then being removed to enable the reinforcements to be cut between the sleepers. Concrete is then cast in the spaces 35 (Fig. 2) between the elements 4, 6 &c. after which the main portion of the sleeper is cast around the anchored re-inforcements. Fig. 5 shows alternative wedging means comprising a wedge 14 driven between counter wedges 15, 16, friction being reduced by greased metal surfaces 31. The elements 4, 6, 7 &c. have wire-receiving grooves (Fig. 2) slightly smaller than the wires and coated with varnishes containing abrasives to improve the anchoring. Also, hardened and knurled metal channels may be placed between the wires and the concrete elements. Specification 453,555 is referred to. The Specification as open to inspection under Sect. 91 describes also wedges 7 made of steel, cast iron or glass. Specifications 338,864, [Class 20 (iv)], and 364,621, [Group V], also are referred to. This subject-matter does not appear in the Specification as accepted.