Abstract: The launching apparatus, including a stayed metallic beam, is provided with two poles, one of which rests on the plank in correspondence of the last pier of the already formed bridge and the other rests on a cantilever end of said bridge length, bracket-like projecting beyond said pier; between the two poles connection stays are provided parallel to each other, either horizontal or inclined, whereas inclined stays are anchored at each of the two poles and at the corresponding length of the metallic beam which is external to the pair of poles.

Abstract: A jack for tensioning cables in prestressed concrete structures, is made to react on the distribution plate with one member of a cylinder-piston system, the other member engaging the strands or wires of the cable to tension them by the lengthening of such cylinder-piston system. The strands pass through the variable-volume chamber of the cylinder-piston system inside guide pipes sliding in one of the members and engaging the other.

Abstract: A system for tensioning stranded or wire cables in prestressed concrete comprises an anchoring head having holes in which are anchored the strands or wires. The anchoring head has a ring in screw-threaded engagement with an exterior surface of the head for providing a reactive support for the anchoring head. An intermediate member is releasably fixed to the anchoring head by rods which extend through holes in the intermediate member and are in screw-threaded engagement with the anchoring head. The intermediate member also has a screw-threaded exterior for engagement with the ring to allow the ring to provide a reactive support for the intermediate member at intermediate stages in a tensioning operation.The intermediate member is releasably connectable to a tensioning jack thus allowing the jack and the intermediate member to be removed from the anchoring head once tensioning is complete.