METHOD FOR PREPARING AND TENSIONING OF REINFORCEMENT RODS Russian patent published in 1996 - IPC

FIELD: civil engineering; production of prestressed reinforced concrete articles. SUBSTANCE: according to method, reinforcement rods are cut to measure, temporary end anchors are made, rods are heated, and placed in stops of forms or supporting platforms. At electric heating, rods lengthen. At cooling, initially comes in contact with left-hand stop of platform is left-hand anchor of rod being stressed. In making temporary end anchors, spacing between them (without taking into consideration deformation of washers and upsetting of heads, pliability of forms and additional lengthening at free placement of rod) is determined by formula: , where: E 444 - modulus of elasticity; l_pl. - spacing between platform stops; - value of yield point of reinforcement rod; K - coefficient taking account of nonresilient ductile properties of reinforcement at electrothermal method of its tensioning (value of coefficient K stands within 1.15-1.65 and depends on grade of reinforcement). EFFECT: high efficiency. 2 dwg