In connection with the nonlinear calculation for the serviceability limit state design checks, I obtain implausibly large values for crack width and deformation in the RF‑CONCRETE modules (see Image 01). What is the cause, and how can I fix the problem?

Please note that in the case of a nonlinear calculation, the reinforcement is not increased automatically. The nonlinear calculation is based on the reinforcement already provided. This provided reinforcement can result from the ultimate limit state designs or from the defined basic reinforcement, for example. The reinforcement applied to the SLS designs can be displayed graphically (see Image 02).

Problem Cause:

If no reinforcement results from the ULS or the basic reinforcement in some areas, the serviceability limit state design is performed without applied reinforcement, which may lead to very high results, for example, for the crack width.

Problem Solution:

You should ensure that reinforcement is available in each area of the structure. This can be done by applying the basic reinforcement (see Image 03).