- Tendon losses are produced by friction, anchorage slip, elastic shortening, creep, shrinkage and relaxation.
- When using the "Typical Tendon" feature, the results for a single strand of tendon are displayed.
From the main menu, select [Results] tab > [Type : Analysis result] > [Table] group > [Results Tables] > [Tendon] > [Tendon Loss]
Tendon Loss(Tendon Group) Output Window
Tendon Group : Select a Tendon Group for which the results will be produced. Tendon Group should be predefined prior to the analysis since the results are produced by Tendon Groups.
Stage: Select a construction stage for which the results will be produced.
Apply : Click the button to produce the tendon results for the corresponding Tendon Group and Construction Stage.
Elem: Element number
Part : Locations at which the tendon results are produced
Stress (After Immediate Loss) : A
Remaining stress in tendon after deducting instantaneous losses.
Instantaneous losses for post-tensioned beams and pre-tensioned beams
Instantaneous losses for post-tensioned beams and pre-tensioned beams are different.
In a post-tensioned beam, friction loss and anchorage slip loss are included in the instantaneous loss. Because elastic shortening loss is considered to have taken place already at the time of prestressing tendons.
In a pre-tensioned beam on the other hand, elastic shortening loss is included in the instantaneous loss. Because friction loss and anchorage slip loss do not take place in a pre-tensioned beam. Elastic shortening loss occurs due to prestress and self weight. Here, only elastic shortening loss due to prestress is considered. The loss due to self weight is included in Elastic Deform. Loss below.
Elastic Deform. Loss: B
Other types of elastic shortening losses, which are caused by subsequent loadings (self weight, live loads, creep, shrinkage, etc.) after the prestressing force is applied, are included. Elastic shortening loss due to prestressing of other tendons as shown in the figure below is also included in Elastic Deform. Loss'.
In order not to consider Elastic Deform. Loss, the Tendon Tension Loss Effect (Elastic Shortening) option must be checked off in the Construction Stage Analysis Control dialog.
The ratio of 'Stress(Elastic Loss)' to 'Stress(After Immediate Loss): B'. Here, 'Stress (Elastic Loss)' represents the sum of 'Stress (After Immediate Loss): A' + 'Elastic Deform. Loss: B'.
Creep&Shrinkage Loss : Stress loss of tendon due to creep and shrinkage
Relaxation Loss : Stress loss of tendon due to relaxation
Stress(All Loss)/ Stress(Immediate Loss) : Ratio of effective stress considering both immediate losses and long-term losses to effective stress considering immediate losses (friction losses and anchorage slip) only
Effective Num.: Outputs the effective number of tendons included in the tendon group. The effective number represents the assumption of an even distribution over the entire cross-section, considering stress concentration within the stress-free zone from the anchorage. For example, if we assume that only 50% of the tendon in the anchorage region is effective due to the stress-free zone, the effective number at that position would be 2.5. When stress-free zone calculation is not considered, the actual number of tendons and the effective number are the same.
To visualize the effective prestressing forces considering tendon losses, you can view the graph by right-clicking on the table and selecting "Tendon Time-dependent Loss Graph." This graph displays the effective prestressing forces excluding losses.
Effective prestress of tendon