Serviceability Limit State
The serviceability limit state design depends on the results of the ultimate limit state design (reinforcement). It is not possible to perform the serviceability limit state design alone.
Existing Load Cases / Combinations
This window section lists all load cases, load and result combinations defined in RFEM.
Normally, the actions and partial safety factors relevant for the serviceability limit state (SLS) design are different from the ones considered for the ultimate limit state. The corresponding combinations can be created in RFEM.
Selected for Design
You can add or remove load cases, as well as load and result combinations as described in Chapter 3.1.1.
For EN 1992-1-1, it is possible to assign different limit values for deflection to the individual load cases, load and result combinations. The following design situations are available:
- Characteristic with direct load
- Characteristic with imposed deformation
- Frequent
- Quasi-permanent
To change the design situation, use the list that you can access by clicking the 
button at the end of the text box.
With the [Details] button you can access the setting options for the individual design situations (see Chapter 4.1.2).
Options
Nonlinear calculation
A license of the add-on module RF-CONCRETE NL is required for the nonlinear design method. The nonlinear analysis for the serviceability limit state is described in Chapter 2.4.8.
Nonlinear analyses performed according to EN 1992-1-1 or DIN 1045-1 can only be carried out for load cases and load combinations, but not for result combinations.
To open the Settings for Nonlinear Calculation dialog box, use the 
button.
This dialog box consists of three tabs.
They are described in Chapter 4.2.
Nonlinear analyses are possible for both the ultimate limit state and the serviceability limit state.
Creep/Shrinkage
In the nonlinear calculation, it is possible to take the influence of creep and shrinkage into account. For more information, see Chapter 2.2.6.
If the check box is selected, you can define the creep coefficient φ (t, t0) and shrinkage strain ε (t, ts) in Window 1.3 Cross-Sections (see Figure 3.19).