A Combination wizard assists you with the task of superimposing load cases in combinations according to the standard. It controls the rules by which the actions are combined in a design situation .
The Combination wizard is activated automatically when creating the model (see the 'Add-ons' tab image). You can also enable or disable the combination wizard in the Load Cases and Combinations dialog box.
A combination wizard manages the specifications according to which the combinations are formed. You can define multiple combination wizards and assign them to the design situations.
The 'Name' is a short description. It is based on the generation type and the analysis type.
Base
The Base tab manages the general specifications of the assistant selected in the 'List' on the left.
Settings
The 'Generate' selection fields determine whether load combinations or result combinations are generated. The generation of load combinations is preset because nonlinear effects and results according to the second-order analysis can only be correctly determined with load combinations.
In the 'Static analysis settings' list, you can select the method of analysis to be used to analyze the combinations (see the Static Analysis Settings chapter).
Options I
If the Structure Stability add-on is activated in the Model's Base Data (license required), you can consider the specifications for the 'stability analysis' when creating the combinations.
The 'Consider imperfection cases' check box controls whether the combinations are created with or without imperfections (see the Imperfection Cases chapter). With the 'Generate same load combinations without imperfection case' option, you can generate combinations once with and once without imperfections.
If you activate the 'Consider initial state from' check box, you can select a load case in the Initial State tab whose deformations represent the initial position for the generated load combinations. Here, too, there is the option to generate combinations both with and without considering an initial state.
The 'Structure Modification' check box offers the option to consider a stiffness adjustment or special treatment of nonlinearities in the load combinations (see the Structure Modifications chapter).
Options II
If you activate the 'User-defined action combinations' check box, no action combinations are created (see the Action Combinations chapter). You then have to combine the actions manually.
With the 'Favorable permanent actions' option, a distinction is made between favorably and unfavorably acting permanent actions during generation. They are included in the superposition with specific partial safety factors. This creates additional load combinations.
With the 'Reduce number of generated combinations' check box, you can generally limit the number of load cases occurring in the load combinations. It is examined which load cases provide positive or negative internal forces and deformations. Subsequently, all positively acting and all negatively acting load cases are summarized. Thus, only those load cases that are relevant for the maximum or minimum values are considered in the combinations.
Result Combinations
When generating result combinations, it is possible to create so-called auxiliary combinations. This option is accessible if the 'Brackets' check box for result combinations is ticked in the 'Load Cases and Combinations' dialog box in the Base tab.
Furthermore, sub-combinations of the 'Superposition' type can be generated, which identify the contained components as separate combinations (see the Result Combinations chapter).
The Generate as permanent superposition check box controls whether non-permanent actions such as imposed loads are considered in the combinations with the criterion 'Temporary' or 'Permanent' acting (see the Result Combinations chapter).
Standard Options
The Standard Options tab manages basic settings for the superposition of specific action categories.
The selection options are aligned with the standard. For EN 1990, for example, it is possible to neglect certain constellations if they have a low probability of occurrence. For example, with certain model properties, the snow load can be disregarded for the leading action wind. If you activate one of the options, the number of generated combinations is reduced accordingly.
Initial State
In the Initial State tab, you can select a load case whose deformations represent the initial position for the created combinations. For example, the influence of a prestress can be considered.
The list in the 'Assigned to' section offers the option to adjust the type of the initial state for the selected load case. The individual options are described in the Load Cases chapter.