received by the International Bureau on 21 March 2017 (21.03.17)

1. A pocket former comprising: a pocket former body, the pocket former body having an outer surface; and a collapsible element, the collapsible element formed on the outer surface of the pocket former body, the collapsible element extending radially outwardly from the pocket former body.

2. The pocket former of claim 1, wherein the pocket former body is tapered from a pocket former outer edge to a pocket former inner edge.

3. The pocket former of claim 1, wherein the collapsible element is generally triangular in cross section.

4. The pocket former of claim 1, wherein the outer surface of the pocket former body

includes textured surfaces, ridges, grooves, recesses, or protrusions.

5. The pocket former of claim 1, wherein the pocket former further comprises pocket former bridges.

6. The pocket former of claim 1, wherein the collapsible element has an exterior surface and wherein the exterior surface of the collapsible element has a curved profile.

7. The pocket former of claim 6, wherein the collapsible element has a cross-sectional angle a and a longitudinal angle β, and wherein the cross-sectional angle a is smaller than the longitudinal angle β.

8. The pocket former of claim 1, wherein the pocket former body further comprises a flex feature.

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9. A pocket former comprising: a pocket former body, the pocket former body having an outer surface, the pocket former body having a first portion and a second portion; and a collapsible element, the collapsible element flexibly coupled to the first portion and the second portion of the pocket former body.

10. The pocket former of claim 9 further comprising a pocket former bridge, wherein the pocket former bridge couples the first portion of the pocket former body to the collapsible element.

1 1. The pocket former of claim 10, wherein the pocket former bridge is less thick than the first portion of the pocket former body.

12. The pocket former of claim 1 1, wherein the pocket former bridge is formed about at least a portion of the perimeter of the collapsible element.

13. The pocket former of claim 10, wherein the pocket former bridge includes a slit between the collapsible element and the pocket former body.

14. A pocket former comprising: a pocket former body; a collapsible element; and a spring mechanism, the spring mechanism mechanically connected to the collapsible element and the pocket former body.

15 The pocket former of claim 14, wherein the spring mechanism comprises:

19 a connecting member, the connecting member mechanically attached or formed integrally with a pivot and wherein the connecting member mechanically connects to the collapsible element; and a spring, wherein the spring connects the pivot to the pocket former body.

16. A method of forming a post-tensioned concrete member comprising: positioning a post-tensioning tendon within a concrete form, the post-tensioning tendon including a tension member, fixed anchor, and a stressing end anchor; positioning a pocket former between the stressing end anchor and the concrete form, the pocket former including: a pocket former body, the pocket former body having an outer surface, the pocket former body having a tension member channel therethrough; and a collapsible element, the collapsible element formed on the outer surface of the pocket former body, the collapsible element extending radially outwardly from the pocket former body; inserting the tension member through the tension member channel of the pocket former body; placing concrete into the concrete form such that the post-tensioning tendon and the pocket former are encased in the concrete; applying force to the pocket former body; collapsing the collapsible element toward the pocket former body; and

20 forming a cavity within the concrete by removing the pocket former body from the concrete.

17. The method of claim 16 further comprising after forming a cavity: applying tensile stress to the tension member; and filling the cavity with filling material.

18. The method of claim 16, wherein the pocket former further comprises pocket former bridges, wherein the pocket former bridges are oriented longitudinally along the pocket former body, the method further comprising: applying force to the pocket former bridges; and separating the pocket former body into two or more longitudinal segments.

19. The method of claim 18 further comprising: flexing the longitudinal segments into a pocket former interior.

20. The method of claim 16, wherein the pocket former body further comprises a flex feature, the method further comprising: bending the collapsible element using the flex feature without separating the collapsible element from the pocket former body.

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