> If I have defined multiple load intervals (e.g. 1,2,3) in GiD for AtenaStatic, then these loading intervals are applied in the calculation one after another, correct?
Yes.
> So if the first interval is a temperature load and the second an external force, the external force is applied once the temperature load is finished.
Yes.
> However, if my previous statement is correct, does the model continues to take into account the temperature of the concrete and reinforcement during the second interval (during the loading)?
Yes, load are incremental. In other words, "0" means "no change" (of the prescibed displacement, force, temperature; imported thermal results are applied as thermal load in static analysis).
> => Is the temperature distribution within the concrete assumed constant during the second loading interval?
Yes. You can check this looking at the ELEMENT_TOTAL_TEMPERATURE values in runtime or postprocessor.