For members or member sets with the activated design properties, there is an additional Design Supports & Deflection tab in the editing dialog box. Here, you can define the boundary conditions for the serviceability limit state design in Aluminum Design. Please note that the settings made here are only relevant if a serviceability configuration is assigned to the objects, and the corresponding design situations are available for the serviceability limit state design checks.
Design Support
Design supports allow for the segmentation of a member or member set for a deflection analysis. The design supports can be assigned via the table at all intermediate nodes of the object. Both nodes of the "Node on Member" type and standard nodes between the members of a member set are recognized.
Select a design support type from the list or create a new one using the
button. Use the
button to edit the selected design support type. The
button allows you to graphically select an existing design support from the model.
For aluminum design, it is possible to use a design support of the "General" type. Further design checks, such as for local load introduction, are currently not implemented. This means that the entries of the support width or depth are not relevant for the aluminum design.
If you do not want to consider the design support for the segmentation, deactivate the "Active for deflection design" option.
Deflection Analysis
After assigning the design supports to a member or a member set, the resulting segments for the respective directions are listed in the Deflection Analysis section of the dialog box. For each design location in the respective segment, the displayed reference length is used to determine the limit value. The automatically determined reference lengths can be overwritten by selecting the "User-Defined Lengths" check box. Please note that if you subsequently change the member length in the model, the previously specified user-defined lengths are not adjusted automatically.
The deflection limit values can be specified in Serviceability Configurations for beams supported on both sides and for cantilevers. According to the defined design supports, the corresponding limit value is taken into account for each segment. A segment with design supports on both sides or with no design supports is regarded as a beam; a segment with a design support on one side is a cantilever. The segment type is also displayed as information in the table.
In the design, you can consider a precamber for each segment and thus reduce the deflection value. The precamber is applied as a single-wave shape in the case of beam segments, and as a linear distribution in the case of cantilever segments. Enter the precamber z/z' or y/y' as a positive value if it is opposite the local member axis z or y, or the auxiliary axis z' or y'. To design the resulting direction, the precamber components are converted into the resulting direction. In the case of design according to EN 1995‑1‑1, the precamber is only taken into account for quasi-permanent design situations.
Use Check direction to specify which deflection values are to be checked in the design. You can select the local axes z and y, as well as the resulting axis, in the list. Furthermore, there are the local auxiliary axes z' or y' for member sets with the members containing incompatible/inconsistent member axis systems.
By selecting the displacement reference, you can influence the deflection values to be checked for the design. If an undeformed system is selected as the reference, the local deformation values uz and uy are taken directly from the results. With regard to the deformed member or member set ends, the deflection values for the design are reduced by the deformation values of the start and end nodes in order to be able to check the local deflections.