In the following the principles of considering rupture or exchange of cables and hangers are explained.
In principle you first have to deactivate the cable, then calculate the load case for the element removal ("DEMO").
If you want to check a series of cables, you have to use the ActOn/ActOff commands.
In this way you can deactivate certain cables and activate them again (which is not possible to do within Stages/Activation).
You also need an envelope containing the loads on the structure at the time when the cable is lost.
So the procedure is as follows:
1.) Prepare an envelope with the loads on the structure during cable loss, e.g.: cable_loss.sup = STG-SUM + 0.5*traffic.sup + etc.
2.) First deactivate a specific cable within the Schedule Actions using the ActOff command (schedule action from the menu Structure change commands):
3.)Then define the respective "DEMO" load case for that cable (load type Actions on element end / Element removal) and refer to the defined envelope (cable_loss.sup) within the definition, e.g.:
Select the superposition line of the envelope to read the results from (MaxN).
4.) Calc this DEMO load case in the Schedule Actions.
The results of that load case can be added/superposed as required:
Note that this DEMO load case is only the correction load case that contains the results due to the forces of the removed cable under the considered loads (cable_loss.sup) that are applied onto the remaining structure (with negative sign).
That means this DEMO load case has to be added to the envelope of the considered loads (cable_loss.sup) and stored into a new envelope to reflect the total situation of the loss of this cable, i.e.: cable_loss_501.sup = cable_loss.sup + DEMO_501.
5.) Use the ActOn command for that cable to activate it again.
6.) Go back to step 2.) to proceed with the deactivation (ActOff) of the next cable…
7.) Finally the particular cable_loss_5xx.sup envelopes can e.g. be superposed with OR into one final envelope to evaluate the most unfavorable situation of all particular cable losses.