# Question

How are elastic compression losses in tendons due to initial pre-stressing and subsequent loads handled in RM Bridge? Where can I see the results, in particular due to stressing of other tendons and due to time-dependent effects of creep, shrinkage and relaxation?

# Answer

The stress distribution given in “*Stages / Tendon actions*” already defines the state of stress in the tendon after pre-stressing (action *Stress*) has been performed and therefore the calculation of the respective pre-stressing load case will have implied the losses due to elastic compression of the member (though this value cannot be viewed explicitly).

For all subsequently calculated load cases elastic compression is always considered for all grouted (action *Grout*) tendons and the results will be stored in these particular load cases. (To consider elastic compression losses also for ungrouted tendons the checkbox “Include El.Comp. losses for ungrouted” in the Recalc-Pad can be checked).

The results of the losses in the tendons due to elastic compression can be viewed in the usual ways as for element results by referring to the respective load case and tendon in various ways as given below:

- Automatically generated
**list file**of the respective load case (at the end of the list are the results for the tendon forces and stresses) – for load cases that are not calculated (e.g. summation load cases) a list file can be generated manually with the schedule action (List/plot action) “ListLc”. - Menu “
**Results / Load Cases**”: switch to “Tendon” and select tendon number (“Tnd”) (switch to display mode “global” to transform the forces in the direction of the tendon) **Rm-Sets**(plots, reports): result component “Tendon stress of given tendon”;**Plot container**…

It is evident, since this applies to all load cases calculated after a particular tendon has been grouted, that in this way also losses of previously grouted tendons due to stressing of subsequent tendons will be considered in the respective pre-stressing load cases of these subsequently stressed tendons.

Time dependent effects due to creep, shrinkage and relaxation are all together considered by the one action *Creep* and therefore are all included in the respective creep load cases. (In this context also note the recalculation option “Time effects (C+S)” and the additional sub-option “include steel relaxation; i.e. results cannot be retrieved individually).

So to see the results/losses in tendons due to these time-dependent effects one has to refer to the respective creep load cases, e.g. the summation load case for creep (“CS-SUM”) for all losses occurring during construction and to the creep load case for “time infinite” (“CS-INF”) for long-term losses respectively.

To compare the stresses in the tendon immediately after construction and at "time infinte" one can refer to the summation load cases "STG-SUM" and "STG-INF-SUM" (= STG-SUM + CS-INF).

In the same way of course any other defined load combination or superposition (envelopes) can be viewed in this regard as well.