Answer:
In this case, the Calculation Method and the type of the 2D model are important.
When using the analytical method (RF‑CONCRETE Deflect), it is possible to perform the calculation in 2D models. When using the nonlinear method (RF‑CONCRETE NL), the calculation for 2D XY (uZ/φX/φY) is not possible. In the nonlinear calculation, shrinkage is represented internally as strain load, which is not possible in this type of 2D model due to the limited degrees of freedom.
Convert 2D to 3D Model
In General Data, you can simply convert a 2D model into a 3D model. For the supports, all degrees of freedom not contained in the 2D model are fixed when converting to a 3D model (see the video).