Prestressed Concrete beam

[parsaparvanehro]

Dear All
As we know for pre-stressed concrete elements the prestressing force must be applied as external load (axial and moment). It is also needed to consider initial stress and strain for tendons before the running the analysis. My question is about the modeling a simply supported pre-stressed concrete beam. If we fix the support in longitudinal (along the beam) direction, when the prestressing force is applied (at the both end of the beam), all the force absorbed by supports. Is it possible to add supports to the model after for example one stage (applying the prestressing load)?