METHOD FOR PRESTRESSING OF SOLID REINFORCED - CONCRETE SLABBED DOUBLE-FRAMEWORK BRIDGES Russian patent published in 2000 - IPC

FIELD: bridge building, applicable in manufacture of prestressed reinforced-concrete slabbed bridge frameworks. SUBSTANCE: the method comprises operations of placement of concrete mix in the falsework, forming of the difference of temperatures of separate members of cross section of the structure at preservation of neutral internal stressed state, fixing of these members at their different temperatures in a single jointly operating cross section and curing of the concreted structure. The framework is concreted in a falsework in the design position on movable and fixed supporting parts located, in turn, on bridge seats. Prior to concreting, the falsework is encased from the bottom for warmth-keeping in heat insulation positioned on both sides from the intermediate support in sections with length "a", which is determined from the given dependence, and the upper surface of the concreted structure is covered with a layer of film. For the remaining part of the framework (except for this section with length 2a) conditions of heat exchange are created, similar for the upper and lower surfaces so as to prevent temperature differential in section. Operation of forming of the difference of temperatures of separate members of cross section at preservation of neutral internal stressed state is accomplished while concrete picks up strength due to the difference of thermal resistance "S" of heat insulation positioned on the upper and lower surfaces of the concreted structure on both sides of the intermediate bridge support in sections with length "a". EFFECT: reduced labour content and simplified job. 1 cl, 6 dwg