Anchoring for prestressed concrete sleepers and manufacturing process

Abstract

The invention relates to an anchorage for applying prestressing forces to prestressing steel in prestressed concrete sleepers for railway construction, as well as a method for manufacturing a prestressed concrete sleeper. To prevent any loss of prestress in the concrete sleeper, even in the long term, a two-part anchorage is proposed, comprising an anchor bell and a nut, connected by an oversized fit between a cylindrical flange on the nut and a hollow cylindrical portion of the bell. The manufacture of concrete sleepers using the late formwork stripping method is based on the idea of ​​mounting, in place of or in addition to the known ribbing or profiling on each steel, the anchorage according to the invention by screwing the nut onto threaded end portions of the prestressing steel and prestressing the steel before concreting and hardening in the sleeper mold.

Claims

- harden the concrete, and - remove the concrete sleeper from the mold.

5. Method according to claim 4, characterized in that at least four prestressing steels (2) are inserted into the cross member mold (6).

6. Method according to claim 4 or 5, characterized in that - to put under stress each prestressing steel (2), a respective clamping sleeve (7) is screwed onto the two free portions (2.3) of the threads (2.2), the two screwed clamping sleeves (7) extending through the openings (6.1) aligned with each other on the front faces (6.2) of the cross mold (6), and - a clamping nut (7.1) is screwed respectively onto the thread of the two clamping sleeves (7), which bear against the front faces (6.2) of the cross mold (6).

7. Method according to claim 6, characterized in that after the hardening step and before the demolding step, the clamping nuts (7.1) and the clamping sleeves (7) are removed.

8. Method according to claim 7, characterized in that after the step of removing the clamping nuts (7.1) and the clamping sleeves (7), the front blind holes (3.1) which remain in the concrete crossbeam (3) are plugged.

9. A method according to any one of claims 4 to 8, characterized in that a prestressing steel (2) is provided which has, between the ends (2.1) having a thread (2.2), a structured surface, in particular ribbed or profiled. [Fig. 1] Figure 1 Figure 2

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