Hi all,
I have a doubt that I have already ask to the technical assistants, but I paste it here so it may help others too.
I want to perform a Construction Stage Analysis of a cable stayed bridge. For a first shot (and for having something to compare with) before thinking about using non linear analysis, I want to perform a linear analysis considering cable sagging at each phase (knowing that it will be tedious to do it stage by stage).
In the User manuals (chapter 7.3.3.2) two actions are explained, UpdEmod and CabSag, which difference I don’t understand quite well. It seems that CabSag is what I am supposed to use for my case, but in chapter 13.1.4.1 it says that the stiffness reduction factors have to be entered by the user and are not calculatedautomatically. That means that I will need to run stage by stage to update my schedule with the proper Ernst modulus based on the axile force in the cable for the previous stage, which is tedious indeed.
But reading the description of the UpdEmod it looks like that function can make the job well if I define a variable that reproduces the Ernst formulation for the E modulus (one variable for each cable). The action only changes the modulus without recalculating, I guess that that means that only the loads to come will be preceding considering that updated Emod, but the past ones remain as they were calculated (a kind of p-delta process for the E modulus), instead of a real nonlinear update (the full force in the cable recalculated with proper value of the Emod). I wonder if the action Cab Sag actually does this (and that’s why it cannot be automatically calculated).
Could anyone please clarify? Thank you very much!