The prestress losses accounted for in SAP2000 can be classified as follows:

• short term losses (immediate losses that occur before and during transfer):
  • anchorage set (anchorage slip losses)
  • elastic shortening
  • friction losses, due to length (or wobble) effect and curvature effect
• long term losses
  • due to concrete creep
  • due to steel relaxation
  • due to shrinkage

Anchorage Set Losses

Losses due to anchorage set are NOT uniformly distributed along the entire length of the tendon. Rather, the length of the tendon affected by anchorage set is calculated as a function of the friction losses:

where,

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  Delta_

  Unknown macro: {set}
  = Anchorage set

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  A_

  Unknown macro: {PS}
  = Cross sectional area of the tendon

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  E_P

  = Young’s modulus of the tendon

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  P

  = frictional loss expressed as a change in force per unit length calculated from a tendon force variation diagram