Process for the manufacture of pretensioned carriageway slabs

Claim 1

Process for the manufacture of carriageway slab or the like which comprises at least two sections, each of which are prestressed throughout their length and breadth and including expansion joints between the sections, each expansion joint comprising the end plates of the two sections separated by a groove and covered by a bridging plate attached to one of the end plates and under which plate the end portion of the adjacent section is slidable, the improvement comprising concreting the main portion of a new section except for a relatively small portion adjacent the expansion joint, said main portion containing embedded jacketed tensioning rods extending from the end plate opposite the expansion joint and into the non-concreted portion of the section, tensioning said tensioning rods and fixing them under tension at the end of said concreted portion, said end plate adjacent said expansion joints containing tendons extending toward the ends of the tensioning rods in the non-concreted area, fixing the position of the two end plates at the expansion joint with respect to each other, securing the ends of the tendons to the ends of the corresponding tensioning members and placing the tendons under tension, concreting the space remaining in said section and then releasing the plates at the expansion joints whereby by the tension applied to the tendons is applied to stress the last applied concrete.