Importance of Tendons in post-tensioned members

Tendons in post-tensioned members are subjected to different amounts of stresses (among themselves) due to following reasons.

The initial lengths of all tendons are not exactly equal.

In a duct, same curvature may not be provided to all tendons compared to an average wire.

There may be some variation in the modulus of elasticity of steel tendons. So, even when they are stretched by same amount, there may be some differences in tendon stresses.

Some wires may be subjected to slip of anchorage and stresses in them may be lower.