received by the International Bureau on 10 June 2016 (10.06.2016)

What is claimed is:

1 . A duct coupler system for use in assembling concrete segments, the system comprising:

a first duct segment;

a second duct segment;

a first coupler attached to the first duct segment and a second coupler attached to the second duct segment, wherein each of the first and second couplers comprises a single, discrete body of non-metallic material, wherein the body of material is annular and wherein each of the first and second duct couplers comprises:

a first end configured for welding to one end of the first or the second duct segment;

a second end opposing the first end, wherein the second end comprises a shelf;

a variable internal diameter; and

a variable outer diameter; and a deformable seal compressed between respective shelves of the first and second couplers.

2. The system of claim 1 , wherein at least one of the first and second couplers attach to the respective first and second duct segments without any sealing member being disposed therebetween.

3. The system according to claims 1 or 2 wherein at least one of the first and second couplers abut the respective first and second duct segments end-to-end without overlapping or extending around the duct segment.

4. The system according to any one of claims 1 , 2 or 3 wherein the first and second couplers comprise plastic.

5. The system according to any one of claims 1 , 2, 3, or 4, wherein the variable internal diameter of the first coupler includes at least a first diameter and a second diameter, the first diameter measuring approximately 58 millimeters (mm) or more.

6. The system of claim 5, wherein the first diameter is approximately 75 mm.

7. The system of claim 5, wherein the first diameter is approximately 99 mm.

8. The system of claim 5, wherein the first diameter is approximately 129 mm.

9. A method of providing a duct coupler system, the method comprising:

providing first and second duct coupler devices, each of the first and second duct coupler devices comprising:

a single, discrete body of non-metallic material;

a first end configured to weld to a duct, or a portion thereof; and a second end opposing the first end, wherein the second end comprises a shelf;

providing first and second duct segments;

welding the first duct coupler device to a first end of the first duct segment, wherein portions between the first duct coupler device and the first duct segment are devoid of a sealing member disposed therebetween;

attaching the second duct coupler device to a first end of the second duct segment; and

compressing a deformable seal between respective shelves of the first and second duct coupler devices.

10. The method according to claim 9, wherein the first duct coupler device and the first duct segment abut end-to-end such that no portion of the first duct coupler device overlaps the first duct segment.

1 1 . The method according to claims 9 or 10, wherein the first duct coupler device and the first duct segment, or portions thereof, include approximately a same internal diameter, within +/- 1 millimeter (mm).

12. The method according to any one of claims 9, 10, or 1 1 , wherein the first duct coupler device and the first duct segment, or portions thereof, include approximately a same external diameter, within +/- 1 millimeter (mm).

13. The method according to any one of claims 9, 10, 1 1 , or 12, wherein the first duct coupler device comprises an inner diameter that measures approximately 58 mm or more.

14. The method according to any one of claims 9, 10, 1 1 , 12, or 13, wherein the first duct coupler device and the first duct segment, or portions thereof, include approximately a same thickness, within +/- 1 millimeter (mm).

15. The method according to claim 14, wherein the first duct coupler device comprises a thickness of approximately 3.54 mm or more.

16. The method according to any one of claims 9, 10, 1 1 , or 12, wherein providing the first and second duct coupler devices comprises providing plastic duct coupler devices.

17. The method according to any one of claims 9, 10, 1 1 , or 12, further comprising casting the first duct segment and the first duct coupler device in concrete.

18. The method of claim 17, further comprising inserting metal rods, bars, or strands through portions of the first duct segment and the first duct coupler.

19. A duct coupler system, the system comprising:

a first duct segment comprising a first end and a second end that opposes the first end; and

a second duct segment comprising a first end and a second end that opposes the first end;

wherein the first end of each of the first and second duct segments comprises a non-metallic first duct coupler device welded thereto, wherein the first duct coupler device does not overlap the first or second duct segments;

wherein the second end of each of the first and second duct segments comprises a second duct coupler attached thereto; and

wherein the first end of the first duct segment is configured to couple to the second end of the second duct segment.

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20. The system according to claim 19, wherein the second duct coupler comprises a duct hub attached to the respective duct segment via an internal sealing member.

21 . The system according to claim 19, wherein the first duct coupler device comprises plastic.

22. The system according to claim 19, wherein the system is cast in concrete.

23. The system according to claim 19 or 20, wherein a sealing member is disposed between the first end of the first duct segment and the second end of the second duct segment.

24. A bridge comprising the system of claim 19.

25. A roadway comprising the system of claim 19.

26. A slab comprising the system of claim 19.

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