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Hardware for post-tensioning



1.Anchorage: there is two types of anchorage: dead end anchorage and live end anchorage. The load shall be applied at the live end.





Anchorage device consists of:

anchorage device


A. Bearing plate: the shape can be round or rectangular. The main function of the bearing plate is to transfer the loads from prestressing tendons to concrete.
bearing plate and wedging plate

B. Wedging plate: strands will be wedged in this plate so strands will transfer
Force to wedging plate and wedging plate will transfer it to bearing plate.











Dead anchorage



2.PT ducts: The strands will be installed inside this duct after casted concrete attained its strength.

Ducts shall be flexible, galvanized, mortar tight and fabricated not lighter than 28 gauge steel, duct diameter should be at least 6 mm bigger than strand nominal diameter and cross section should be at least twice of the net area of strands.




3. Couplers: is an essential part of post tensioning where a continuous tendon is laid over a few spans of girders in bridge construction. Due to the frictional loses that occurs during stressing, Couplers are used to provide optimum prestressing efficiency. 50% of tendons shall be coupled in the same area. According to Aashto (5.10.3.5) code coupling all tendon at the same section will reduce the concrete section and increase creep.



4. Grout Inlets, Outlets, Valves, and grout caps: 
Grout inlets shall be fixed at high points to check the grout quality while flowing from one end to others.
Outlets shall be fixed at low points to drain water or grout in case of blockage or grout process interruption.
Grout caps shall be fixed on bearing plate after completion of stressing and cutting strands and before grouting so grouts will not leaks from wedge plate.









grout cap

grout inlet

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