Load Case Code Combinations dialog - Full/Simplified Combinations

Access

1. Click Loads Automatic Combinations.
2. Select a full or simplified automatic combination, and then click More.

Cases tab

Use the Cases tab to select the load cases which are already defined for the structure and will be used to create code combinations.

Active Case Selection

Lists the defined load cases and their natures.

Appropriate coefficients used during the creation of the combination are defined for each load case defined by a selected nature.

Select the cases to include in the code combination.

Note: By default, all cases are selected.

Edit parameters

Select a case, and then click this button to open the Parameters dialog which allows you to modify the Label and Coefficient for the case.

Note: By default, the case label is automatically generated according to the case's nature.

Combinations tab

Use the Combinations tab to define the code combinations.

Select the codes and templates to use for the combination.

Groups tab

Use the Groups tab to define or display sets of load combinations connected by logical relationships.

All dead loads are connected in one group of combined loads acting simultaneously. Snow and wind loads create a separate group of self-exclusive loads for which the occurrence of one case excludes the other. All other live loads occur as loads which are not inter-related.

Relations tab

Use the Relations tab to define relationships between load cases, and in particular groups, by using the logical operators and, or (inclusive) , and or (exclusive) .

Robot creates the groups and relationships automatically. This solution resolved the problem of base combinations. For more advanced combinations, options found on the Relations tab can be used. This lets you create logical operations on groups of cases within natures. When creating the operations, you can use brackets to join or exclude selected groups of cases.

For example, suppose the following 3 groups of load cases are defined in a structure: G1, G2 and G3. The logical operators function in the following manner:

• AND - Simultaneously activates all loads (loads from load cases G1, G2 and G3 are applied simultaneously to the structure). You can represent it symbolically as: G1 G2 G3
• OR (EXCLUSIVE) - This operator is used when loads from a particular load group are mutually exclusive (loads from load case G1, or G2, or G3, will be applied to the structure). You can represent it symbolically as:

  G1

  G2

  G3

• OR (INCLUSIVE) - This operator allows all possible combinations between groups of load cases. You can represent it symbolically as:

  G1

  G2

  G3

  G1 G2

  G1 G3

  G2 G3

  G1 G2 G3.

See also:

Functioning of operators in groups for dead loads

Simulteneity coefficients for sub-natures of a live load

Simplified tab (Simplified combinations only)

For more elaborate tasks (over 10 load cases for which to create code combinations), creating code combinations can be time consuming. The Simplified tab is used for defining simplified code combinations that generate extreme combinations, because of a specific result or their combination.

For this type of case, you give a list of points and define the determining value (indicated force, moment, or stress). Robot decides which combinations meet these conditions, and only those values are saved as a code combination for the selected bar. For an interaction between 2 selected values, Robot tries to select the extents of those variables.

Selection tab (Simplified combinations only)

For more complex tasks, you can create simplified code combinations for selected structure nodes and or bars using the Selection tab:

• All bars (values selected on the Simplified tab) are verified for all bars of a structure or bars from a given list (values selected on the Simplified tab) are verified for the bars of a structure you specify.
• All nodes (values selected on the Simplified tab) are verified for all nodes of a structure or nodes from a given list (values selected on the Simplified tab) are verified for the nodes of a structure you specify.

See also:

Definition of abbreviated case names (snow/wind loads) in generation of code combinations