The deactivated loading during construction stage still has influence on PostCS stage

Question:

Hi sir,
Why the loading in the construction stage(bridge erection machine load) will also have an impact on the completion phase even after deactivation. For example, the erection machine load(seperated from CS dead load denoted as: erection load 3) in my test model still shows pile reaction force in the 10-30 years stage(at this time, there is no any erection machine loading on the structure and all the loading before had been deactivated.). We can confirm that this value is not min/max value during construction stage, from my understanding, the Erection load 3 should be 0 after all erection machine load had been deactivated. Can you explain this? Thanks!


Answer:

Firstly let me first explain the method of deactivation of loads in construction stage in midas civil.
In midas civil, when a load is deactivated, the opposite load is applied to original positions. 
So, if load of 10 kN is applied to structure in +Z direction at a point which is activated in CS1. Then, while deactivating this load in CS2, midas will apply 10 kN load in-Z direction at that same point.
In the model, the machine load P88-P89 hang load group is activated at CS2-P88-P89 hang construction stage as shown below.


Now, this load is deactivated at CS2-tendon construction stage. 


So, structure configuration has changed when load is deactivated. Thus, the opposite load for P88-P89 hang at deactivation will not yield same reaction value. Thus, the residual reactions are left in the structure.
Similarly, these residual reactions remains for further construction stages.
Creation date: 6/4/2021 3:45 PM (jatin2010)      Updated: 6/4/2021 3:45 PM
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