Annular three-dimensional structure usable in particular as reinforcement

An annular three-dimensional structure, which may be used in particular as reinforcement, comprising a regular interleaving of elongated filiform elements distributed in first, second, third and fourth families, the elements of each family being disposed in parallel, regularly spaced apart sheets themselves constituted by elements extending substantially parallel to one another and being regularly spaced apart, the sheets of the first and second families being alternately disposed in adjacent parallel layers and, similarly, the sheets of the third and fourth families being alternately disposed in adjacent parallel layers, these latter being inclined with respect to those of the first and second families, the elements in each sheet having a different orientation from that of the elements of the adjacent parallel sheet of another family, said structure appearing as being formed by the regular repetition of a basic motif, or unit cell, inscribed in a parallelepiped containing at least one segment of element of each of the four families, these elements being oriented substantially along the four long diagonals of this parallelepiped, wherein the elements of at least the first and second families are incurved, the direction of incurvation of the elements of the first family being opposite that of the elements of the second family, and the unit cells of the structure conserve substantially the same orientation with respect to the axis of the structure, all around this axis.