Table of Contents
What is elongation in post tension?
Elongations are a key to determining the forces inside post-tensioned tendons. For that reason, elongations have always been used as a way to assess the post-tensioned forces within the tendons because the tendon force is directly proportional to the elongation through a known equation.
How do you find the elongation of strands?
a) Elongation Calculation :
- a) Elongation Calculation :
- Design load in N — P.
- Length of Tendon in mm — L.
- Area of Strand in mm2— A.
- Young’s Modulus in N/ mm2— E.
- Elongation (e) = P x L / A x E in “mm”
- b) Modified Elongation Calculation :
- Area of Strand in mm2— A.
When should you stress post tension cables?
Post tensioned slabs should be stressed when the concrete strength designated by the engineer’s plan is reached. The practice of MLAW has been to apply stress when the concrete reaches 2000 psi.
How much tension is on a post tension cable?
A post tension slab is a concrete slab with steel cables running through it that have been placed under 33,000 +/- pounds of tension. This tension makes the concrete slab and foundation much stronger than concrete without reinforcement and helps reduce cracking.
How is post tensioning done?
Post-tensioning is a method of prestressing in which the tendons are tensioned after the concrete has hardened and the prestressing force is primarily transferred to the concrete through the end anchorages.
How Post Tensioning is done?
What happens if you cut post tension cable?
Corners typically contain cables. Cables typically run East to West or North to South. Do NOT cut into a post tensioned slab if there is a chance you will rupture a cable. People have been dismembered and killed when cables are cut and burst out of the concrete.
Is post-tension better than rebar?
Post-tensioning, which is a form of prestressing, has several advantages over standard reinforcing steel (rebars): It reduces or eliminates shrinkage cracking-therefore no joints, or fewer joints, are needed. Cracks that do form are held tightly together. It allows slabs and other structural members to be thinner.