DUCT MAKING TOOL FOR REINFORCEMENT BEING STRESSED Russian patent published in 2002 - IPC

FIELD: construction engineering; bridge engineering. SUBSTANCE: tool used for producing reinforced concrete structures with large spans of 30-100 m is made in the form of corrugated case to follow shape of tube formed of metal stripe whose width-to-thickness ratio is 35-140; corrugations of case are made to follow shape of turn pairs of double entry thread; distance in pair between turns is 2.1-2.4 of corrugation height. Distance between corrugation pairs is 3.0-4.0 of corrugation height; ratio of corrugated case diameter to width of metal stripe which forms mentioned case is 0.8-7. Corrugated case may be composed throughout its length of sections joined together by sleeve screwed on their ends and is formed by part of corrugated case with distance between corrugations and pairs of corrugations equal to respective distances of sections being joined; sleeve diameter exceeds that of sections being joined by 3-7 times. In vicinity of sleeve ends each section of corrugated case may be sealed with stripe on section overlapping no lesser than distance between adjoining pairs of corrugations. EFFECT: enhanced reliability and service life; reduced material consumption of building structures. 3 cl, 2 dwg