METHOD FOR MANUFACTURING PRE-STRESSED REINFORCED CONCRETE BEAM Russian patent published in 2001 - IPC

FIELD: construction engineering. SUBSTANCE: method is used for manufacturing new type of continuous multispan reinforced concrete beams with alternate pre-stress along reinforcing rods made of high- strength steel. Method involves installation of reinforcing frame into form, its fixation in form, pre-stressing of longitudinal reinforcement, filling form with concrete mix, and release of reinforcement stress when concrete becomes fast. In addition during beam concreting parts of reinforcing rods which must be pre-strained or pre-compressed are kept open; when concrete becomes fast pre-straining of reinforcement is effected on parts of reinforcement compressible by external load by means of muffs screwed on reinforcing rods; pre-compression is effected on extended parts of reinforcement; concrete is not exposed to pre-straining in area where there is pre-compressing stress in reinforcement which has cohesion with concrete. EFFECT: provision for changing pre-stress sign according to curve showing alternate-sign bending moments as function of external load. 9 dwg