AN ANCHORING HEAD FOR STRANDS OR CABLES FOR TENSIONING METAL OR CONCRETE STRUCTURES

Abstract: An anchoring head for strands or cables, according to which the front bearing plate (20) is provided with couplings or connections (21) for the strands that are arranged at the vertices of adjoining equilateral triangles. An improvement of the invention provides that the pe­ riphery (22) of the plate (21) is provided with coupling members (25, 26; 27, 28) securing one plate with respect to the adjoining plates. Particularly, said contour or outline (22) may sub­ stantially follow the center lines of the sides of said triangles. On the plate ribs and sleeves are also provided.

Description: "AN ANCHORING HEAD FOR STRANDS OR CABLES FOR TENSIONING METAL OR CONCRETE STRUCTURES". This invention relates to a head for positioning the ends of an assembly of cables or strands prearanging the same for tensioning, and subdividing the stresses due to said tensioning, so that these stresses will be applied adeguately to the structure to be tensioned. Hitherto, the diatribution 9f the strands or cables on the outer front plate of a head has been carried out, so that one or more jacks putting the cable or individual strands under tension can be applied thereto. The arrangement is such that the overall stress acts on the periphery of the outer front plate of the head. This involves a not optimum utilization of the available space and a non uniform distribution of the stresses to the plate, and accordingly to the metal or concrete structure on which said plate is mounted, making it necessary to dimension the metal or concrete structure for stresses existing only in zones of reduced dimensions. oreover, the positioning obtained is not always stable since the outer front plate or plates may be displaced during casting. Therefore, it is the object of the present invention to provide on the structure to be tensioned by means of the plate a perfect positioning of the cables or strands together with a maximum utilization of the available space and the most uniform distribution of the stresses. It is a further object of the invention to improve the anchoring of the plate to the concrete. The main object has been acomplished by providing that each connection of the strands or cables to the head bearing plate is provided at the vertices of a lattice formed by adjoining equilateral triangles. An improvement of the invention provides that the plate periphery is provided with mutual coupling members defining the position of one plate relative to another plate. Particularly, it is contemplated that on at least some of its sides the plate periphery follows the same equilateral tri'angle configuration, passing approximately in the center lihes of the triangle sides, whereby a plate can be arranged near another plate, the equilateral triangle lattice remaining unaltered also in the connecting zone between a plurality of adjoining plates. Thus, the plates can be coupled either by superimposition or by juxtaposition or side by side arrangement, forming a set of mutual joints preventing the plates from being displaced during the concrete cast step, thus maintaining surely the position defined by the project. Moreover, at each connection of a strand or cable, which is carried out with a hole into which said strand or cable penetrates, a sleeve is preferably provided for improving the anchoring of the plate to the concrete. The possibility of strengthening the plate with ribs is also provided. These extend between the various connecting locations of the cables or strands. The present invention will now be better explained with reference to an exemplary embodiment that has been shown in the figures of the accompanying drawing, in which: Fig. 1 is a side, partly sectional view of a head according to the present invention, the sectional view being taken along line 1-1 of Fig. 2; Fig. 2 is a view of the front plate from the side 2-2 of Fig. 1; Fig. 3 is a sectional view taken along line 3-3 of Fig. 1; and Fig. 4 is a view similar to Fig. 2, but showing a plurality of juxtaposed plates. From the drawing it will be seen that a head according to the present invention comprises a cone 10 secured to the end of a sheath 12, having a series of tubes 11 branching off therefrom, one for each cable or strand, which tubes act as coatings therefor. They serve for leading the strands to the sleeves 24, then to the connections formed of holes 21, which are provided in the front plate 20. The series of holes 21 is arranged at such a position as to form a lattice of adjoining equilateral triangles, at the vertices of which said holes 21 are provided. Reinforcing ribs 23 are provided between the holes 21. The periphery 22 of plate 20 is provided with mutual coupling members 25 and 26 securing one plate relative to the adjoining plates. Further portions of this periphery 22 are shaped with projections 27 and recesses 28 which work as coupling members and placed in such a way as to be inserted between the sides of the various equilateral triangles, so that the arrangement of the strands of a plurality of adjoining plates always corresponds to the vertices of equilateral triangles, as shown in Fig. 4. Thus, in this figure it will be seen that the distance d between two holes 21 remains unaltered even if measured between two holes 21 pertaining to two adjoining plates 20.

Claims: CLAIMS 1. An anchoring head for cables or strands, characterized in that the front bearing plate (20) to the structure is provided with connections (213 for the strands which are arranged at the vertices of adjoining equilateral triangles. 2. A head according to Claim 1, characterized in that the periphery (22) of the front plate (20) has mutual coupling members (25, 26; 27, 28) preventing the displacement of the plates, for example during the concrete cast step. 3. A head according to Claim 2, characterized in that the periphery (22) of the front plate (20) is at least partly shaped to be included wi'th proÅaections (.27) and recesses (28) of conjugate shape, whereby a plurality pf plates (20) can be juxtaposed, so that also for adjoining platen the lattice arrangement of equilateral triangles remains unaltered. 4. A head according to any of Claims 1, 2 or 3, characterized in that at each connecting zone (21) of the strands or cables the front plate (20) is provided with a sleeve (24). 5. A head according to any of the preceding claims, characterized in that the front plate (20) is provided with ribs (23) extending between two connections (21) of the cables or strands.

Inventors: PREVIDINI, CESARE
Applicants: PONTEGGI EST S.P.A.
Application year: 1981
Main classification: E04C5
IPC codes: E04C5