Prestressed concrete structure, a method of producing this structure, and elements for implementing the method

Claim 1

A prestressed concrete structure behaving like a hollowed out slab, comprising two reinforced or prestressed concrete slabs which are positioned opposite each other in generally parallel spaced relationship and which are connected by a lattice work of concrete bars positioned in and across the space between the slabs, the lattice work being mainly composed of a plurality of prefabricated concrete triangle elements, each triangle element comprising at least one group of at least two bars and at least one cross piece positioned generally along the three sides of a triangle, the meeting point of the two bars forming the apex of the triangle and being adjacent one of said slabs and the cross piece being parallel to and adjacent the other of said slabs, a plurality of cables for prestressing the whole of the structure, and at least two concrete cable anchor members which are spaced apart longitudinally and positioned between and extend across the space between the two slabs and which are integral with at least one of the slabs, said cables extending generally longitudinally between said anchor members and having opposite end portions anchored respectively therein, and each of said cables extending from and adjacent each of its said anchored end portions in the space between said slabs first angularly toward its other end portion and angularly toward one of said slabs, then angularly in free passage through said one slab, and finally in parallel adjacent relationship with said one slab and on an opposite side thereof to its said opposite end portion, and each of said cables adjacent its anchored end portions also passing angularly in free, unconnected and unobstructed passage through said space and the lattice work between said slabs.