Coated PC steel stranded cable

1. A coated prestressed concrete (PC) steel stranded cable comprising:

a stranded cable in which a plurality of elemental wires each composed of steel are twisted together;

an anti-corrosive coating that coats an outer circumference of the stranded cable; and

an optical fiber provided at a position corresponding to a strand groove in the stranded cable,

the stranded cable having a plurality of outer circumferential elemental wires constituting the outer circumference of the stranded cable, and an inner circumferential elemental wire or central elemental wire adjacent to the plurality of outer circumferential elemental wires, wherein the inner circumferential elemental wire or central elemental wire is located at a center in a radial direction of the coated PC steel stranded cable,

each one of the plurality of outer circumferential elemental wires having a diameter smaller than a diameter of the inner circumferential elemental wire or the central elemental wire,

the anti-corrosive coating having a filler portion provided at a triple point surrounded by the plurality of outer circumferential elemental wires and the inner circumferential elemental wire or the central elemental wire,

the optical fiber being disposed at the strand groove formed between adjacent outer circumferential elemental wires of the stranded cable, the optical fiber being entirely embedded in the anti-corrosive coating without using an adhesive agent,

the plurality of outer circumferential elemental wires comprising a first set of outer circumferential elemental wires, a space being formed between at least two adjacent outer circumferential elemental wires of the first set, the space being filled with the filler portion,

the plurality of outer circumferential elemental wires comprising a second set, at least two adjacent outer circumferential elemental wires of the second set contact one another, and

each of the outer circumferential elemental wire, the inner circumferential elemental wire, and the central elemental wire consists of a single strand.

2. The coated PC steel stranded cable according to claim 1 , wherein at least one adjacent outer circumferential elemental wire is in both the first set and the second set.

3. The coated PC steel stranded cable according to claim 1 , wherein the first set and the second set include different outer circumferential elemental wires.

4. The coated PC steel stranded cable according to claim 1 , wherein the adjacent outer circumferential elemental wires in the first set are mutually exclusive of the adjacent outer circumferential elemental wires in the second set.

5. A coated prestressed concrete (PC) steel stranded cable comprising:

a stranded cable in which a plurality of elemental wires each composed of steel are twisted together;

an anti-corrosive coating that coats an outer circumference of the stranded cable; and

an optical fiber provided at a position corresponding to a strand groove in the stranded cable,

the optical fiber being disposed at a triple point surrounded by a plurality of outer circumferential elemental wires and an inner circumferential elemental wire or central elemental wire, the plurality of outer circumferential elemental wires and the inner circumferential elemental wire or the central elemental wire constituting the stranded cable, the inner circumferential elemental wire or the central elemental wire being adjacent to the plurality of outer circumferential elemental wires, wherein the inner circumferential elemental wire or central elemental wire is located at a center in a radial direction of the coated PC steel stranded cable,

each one of the plurality of outer circumferential elemental wires having a diameter smaller than a diameter of the inner circumferential elemental wire or the central elemental wire,

the anti-corrosive coating having a filler portion provided between the elemental wires,

the plurality of outer circumferential elemental wires comprising a first set of outer circumferential elemental wires, a space being formed between at least two adjacent outer circumferential elemental wires of the first set, the space being filled with the filler portion,

the plurality of outer circumferential elemental wires comprising a second set, at least two adjacent outer circumferential elemental wires of the second set contact one another, and

each of the outer circumferential elemental wire, the inner circumferential elemental wire, and the central elemental wire consists of a single strand.

6. The coated PC steel stranded cable according to claim 5 , wherein the stranded cable includes the central elemental wire, and the plurality of outer circumferential elemental wires helically twisted around an outer circumference of the central elemental wire, and

the space between adjacent outer circumferential elemental wires has a length equal to or more than a diameter of the optical fiber.

7. The coated PC steel stranded cable according to claim 5 , further comprising: an outer coating that coats the outer circumference of the anti-corrosive coating.

8. A coated prestressed concrete (PC) steel stranded cable comprising:

a stranded cable in which a plurality of elemental wires each composed of steel are twisted together;

an anti-corrosive coating that coats an outer circumference of the stranded cable;

an outer coating that coats an outer circumference of the anti-corrosive coating; and

an optical fiber provided at a position inwardly of an outer circumferential surface of the outer coating and corresponding to a strand groove in the stranded cable,

the anti-corrosive coating having a surface provided with a press-fit groove in which a portion of the optical fiber is press-fitted,

the optical fiber being fixed by the anti-corrosive coating without using an adhesive agent,

the stranded cable having a plurality of outer circumferential elemental wires constituting the outer circumference of the stranded cable, and an inner circumferential elemental wire or central elemental wire adjacent to the plurality of outer circumferential elemental wires, wherein the inner circumferential elemental wire or central elemental wire is located at a center in a radial direction of the coated PC steel stranded cable, and

each of the outer circumferential elemental wire, the inner circumferential elemental wire, and the central elemental wire is single wire.

9. A coated prestressed concrete (PC) steel stranded cable comprising:

a stranded cable in which a plurality of elemental wires each composed of steel are twisted together;

an anti-corrosive coating that coats an outer circumference of the stranded cable;

an outer coating that coats an outer circumference of the anti-corrosive coating; and

an optical fiber provided at a position inwardly of an outer circumferential surface of the outer coating and corresponding to a strand groove in the stranded cable,

the anti-corrosive coating having a surface provided with an irregularity for increasing frictional resistance with the optical fiber and the outer coating, and

the irregularity being smaller than an irregularity formed by the strand groove,

the stranded cable having a plurality of outer circumferential elemental wires constituting the outer circumference of the stranded cable, and an inner circumferential elemental wire or central elemental wire adjacent to the plurality of outer circumferential elemental wires, wherein the inner circumferential elemental wire or central elemental wire is located at a center in a radial direction of the coated PC steel stranded cable,

each one of the plurality of outer circumferential elemental wires having a diameter smaller than a diameter of the inner circumferential elemental wire or the central elemental wire,

the plurality of outer circumferential elemental wires comprising a first set of outer circumferential elemental wires, a space being formed between at least two adjacent outer circumferential elemental wires of the first set, the space being filled with the filler portion,

the plurality of outer circumferential elemental wires comprising a second set, at least two adjacent outer circumferential elemental wires of the second set contact one another, and

each of the outer circumferential elemental wire, the inner circumferential elemental wire, and the central elemental wire consists of a single strand.

10. A coated prestressed concrete (PC) steel stranded cable comprising:

a stranded cable in which a plurality of elemental wires each composed of steel are twisted together;

the stranded cable having a plurality of outer circumferential elemental wires constituting the outer circumference of the stranded cable, and an inner circumferential elemental wire or central elemental wire adjacent to the plurality of outer circumferential elemental wires, wherein the inner circumferential elemental wire or central elemental wire is located at a center in a radial direction of the coated PC steel stranded cable;

an anti-corrosive coating having an outer circumferential portion that coats an outer circumference of the stranded cable;

an outer coating that coats an outer circumference of the anti-corrosive coating; and

an optical fiber provided at a position inwardly of an outer circumferential surface of the outer coating and corresponding to a strand groove in the stranded cable so as to follow expansion and contraction of the stranded cable,

each one of the plurality of outer circumferential elemental wires having a diameter smaller than a diameter of the inner circumferential elemental wire or the central elemental wire,

the plurality of outer circumferential elemental wires comprising a first set of outer circumferential elemental wires, a space being formed between at least two adjacent outer circumferential elemental wires of the first set, the space being filled with the filler portion,

the plurality of outer circumferential elemental wires comprising a second set, at least two adjacent outer circumferential elemental wires of the second set contact one another, and

each of the outer circumferential elemental wire, the inner circumferential elemental wire, and the central elemental wire consists of a single strand.

11. The coated PC steel stranded cable according to claim 10 , wherein the optical fiber is fixed by an adhesive agent to the strand groove on a surface of the anti-corrosive coating.

12. The coated PC steel stranded cable according to claim 10 , wherein the optical fiber is fixed by the anti-corrosive coating without using an adhesive agent.

13. The coated PC steel stranded cable according to claim 12 , wherein the optical fiber has a portion embedded in and incorporated with the anti-corrosive coating.