Which of the following losses occurs only in post-tensioning pre-stressed concrete structures

Question

Question

This question was previously asked in

UKPSC AE Civil 2013 Official Paper I

Answer 1

Concept:

Loss due to friction and anchorage slip occurs only in the post-tensioned beam.

In prestressed concrete, the most important parameter is the prestressing force.
If the prestressing force reduces with time, prestresses also get reduced.
Various reductions of the prestressing force are termed as the losses in prestressing.
Total loss of prestress consists of those losses which are instantaneous at the transfer stage as well as those which are time-dependent.

Important Points

Losses of prestress:

	Pre-tensioning		Post-Tensioning
1.	Elastic shortening loss	1.	No elastic shortening loss in cables if pulled simultaneously, however, losses will be there if cables are pulled are by one.
2.	Creep loss	2.	Friction loss
3.	Shrinkage loss	3.	Anchor slip loss
4.	Relaxation loss	4.	Creep loss
		5.	Shrinkage & Relaxation