Answer:
The effect results from the shrinkage application in the nonlinear deformation analysis in RF‑CONCRETE Surfaces. The shrinkage is considered as a change in length or a shortening in the form of an additional load.
Since the reinforcement prevents the shrinkage, an asymmetrical reinforcement of 2.57 cm²/m on the top and 5.24 cm²/m on the bottom, for example, can reduce the cross-section on the top side because of the smaller steel core. This results in an additional curvature (longer bottom side), which occurs in addition to the actual deformation.
If the difference between the steel cross-sections on the top and bottom becomes even larger (for example, 2.57 cm²/m on the top and 10.47 cm²/m on the bottom), this additional curvature becomes larger as well.
You can create additional design cases in the file and, for example, analyze symmetrical reinforcement, or deactivate the shrinkage as a test.
More information about applying shrinkage in a nonlinear deformation analysis can be found in technical article 001574 on our homepage.
Technical Article | Differences Between Analytical and Nonlinear Deformation Analysis of Reinforced Concrete
