In the Surfaces tab of the 'Serviceability configuration' dialog, you specify the limit values that apply to the deformations of surfaces.
As for the members, different design situation types exist for serviceability limit state designs, which vary depending on the design standard. For each combination type, you can specify specific limit values for deflections. They are related to the lengths of the structural components.
The list next to the 'Definition type' provides several options for defining a limit value (see image Defining reference of deformation):
- Relative value: The limit value is defined in relation to the length of the surface.
- Absolute value: The value of the maximum deflection is defined directly.
- Sum of relative and absolute value: The limit value is the sum of the relative value and the absolute value.
- Min. of relative and absolute value: The limit value is the smaller value of the relative or absolute value.
- Max. of relative and absolute value: The limit value is the larger value of the relative or absolute value.
Depending on the support of the structural component – surface supported on both sides or cantilever surface supported on one side – different limit values of the deflection are usually relevant. This support is to be defined as the 'Surface type' in the properties of the surface or the surface set in the Deflection tab. There you can also define whether the maximum displacements refer to the undeformed system, a deformed reference plane, or a parallel surface, and specify how the reference length is to be determined.
If necessary, adjust the default limit values for the deformation analyses of the objects.