To provide a flat anchorage device for a post-tensioned type prestressed concrete floor slab, which can be easily worked and which enables the collective tensioning and anchoring of a plurality of prestressing steel strands, the post-tensioned type prestressed concrete floor slab using the anchorage device, and a construction method for the post-tensioned type prestressed concrete floor slab.

This flat anchorage device for introducing prestress into a concrete floor slab by a post-tensioning system comprises an anchor head in which a plurality of wedge-mounting tapered holes for tensioning and anchoring the prestressing steel strands are drilled in such a manner that axis lines are orthogonal to a planar surface of the anchor head and parallel to one another, and a bearing plate which has the length of a trumpet-shaped pipe portion adjusted in such a manner as to correspond to the anchor head. In the construction method for the post-tensioned type prestressed concrete floor slab, the plurality of prestressing steel strands, which are pulled out in parallel from the anchor head by using the anchor head, are collectively tensioned and anchored by means of a jack capable of tensioning and anchoring them in the same direction at a time; and juxtaposed cable sheaths are serially connected together by means of a hose, so that grout can be injected.