the elastomer 31 adheres to the wires by surface adhesion preferably by chemical bonding with the sheath 22 in order to increase this adhesion as an alternative the matrix may be a lubricant such as wax or grease so as to reduce the friction between the wires and the sheath in the fourth embodiment depicted in fig5 the reinforcement 40 differs from the reinforcement 30 described with reference to fig4 in the exterior shape of the sheath 42 the exterior wall 46 of this sheath is no longer of lobed shape in cross section but of polygonal shape this shape makes the reinforcements or strands easier to juxtapose in order to form a cable 50 like the one depicted in fig6 the spaces between the strands 40 can be occupied by a matrix similar to the one described hereinabove as an alternative it is possible to juxtapose reinforcements 40 the wires of which have different diameters from one reinforcement to another the strand thus obtained according to one of the embodiments has a mechanical strength an elastic modulus fatigue performance and ductility whose values are equivalent and even equal to those of each wire of which it is made in order to be packaged and transported to the site of the building work the strand is wound onto a drum making one full twist over one turn the pitch is of the order of one to three meters which means that residual stresses in the elastic region are stored in each constituent wire furthermore the reinforcement obtained according to one of the embodiments is used.