Standards such as EN 1990 and ASCE 7 provide rules for combining independent actions in various design situations. Actions are independent of each other if they arise from different origins and if the correlation between them may be neglected with regard to the reliability of the structural system.
In accordance with this concept, actions to which load cases are assigned must be defined for the automatic superposition. The action categories defined for the load cases (see the Load Cases chapter) form the basis for classifying the load cases.
Main
The Main tab manages the criteria for classifying and superimposing load cases. The "List" shows all the action categories you used when creating the load cases.
Settings
The "Action category" of the selected action is preset. It corresponds to the category of the corresponding load cases. In the Assignment tab, you can check the load cases that are assigned to the action.
The "Action type" controls how the load cases of the action are taken into account for the superposition. There are three options available for selection in the list (see the Actions image):
- Simultaneously: All load cases of the action can be combined as required. They can occur together in one combination.
- Alternatively: Only one of the load cases of the action can be effective in the combination. This is the case, for example, with wind from different directions.
- Differently: Differentiated relations between the load cases in the action are possible. In the "Assignment" tab, another column appears where you can assign each load case to a group. This way, you can control which load cases of the action act simultaneously or alternatively.
Assignment
Particular load cases are assigned to each action. The classification is carried out according to the action categories that have been defined for the individual load cases (see the Load Cases chapter).
If you want to remove a load case from an action, double-click the entry.