Details about post-tensioning work
Post -Tensioning work is segregated into following three major parts - Profiling, Stressing, and Grouting.
Profiling:
a. After studying the drawings carefully, determine the type of tendons, layout, locations, and number of strands per tendon, sequence of laying, number of tendons per pour, etc.
b. Measure the required materials like Tube Units, Bearing Plates, Wedges, Sheathing and Pre-stressing Steel (HTS).
c. Work out the cut length of Strand along with Jack Grip length & profile for each tendon and produce Strand cutting schedule according to drawing. HT Strand should be sliced with cut-off wheel/abrasion blade.
d. HT Strand should be uncoiled with coil dispenser and it should not keep in touch with soil or dust at the time of cutting.
e. Mark the tendons according to tendon layout drawing once the formwork & reinforcement are finished.
f. Set the fabricated tendon support bars (bar chairs) firmly at every 1m (max.) span in accordance with the tendon layout and profile drawings.
g. Place the sheathing over the tendon support bars according to the tendon layout drawing and fix the ducts with couplers and seal the joint with self adhesive tape.
h. Thread the necessary number of Strands into Sheathing as stated in the Tendon type (strand schedule) and bind the sheathing with Bar Chairs by applying binding wires firmly.
i. Profiling of Tendons, both horizontally and vertically according to drawings and holding it firmly to get rid of any troubles in profile throughout concreting.
j. Set the Stressing anchorages and create Dead-end anchorages position with reference to the layout drawing. Secure the grout vents at end portions and air vents at high profile locations and seal it in a perfect manner.
k. Secure Bursting and Spiral reinforcements at the anchorages zones on the basis of the details provided in drawing.
l. Final examination of all Tendons for profiling, supporting and sealing after the fulfillment of reinforcement and formwork works and prior to concreting.
