Code-Generated Automatic Load Combinations for {Type} Frame Design {Code} Form

Additional form:  Design Load Type

Program design is based on a set of loading combinations. This topic describes automatically generated load combinations for the specified design code. If the automatically generated load combinations are acceptable, no definition of additional load combinations is required. If additional load combinations are required, user load combinations can be defined using the Define menu > Load Combinations command.

Use the Code-Generated Automatic Load Combinations for {Type} Frame Design - {Code} form to review, and if necessary specify, the limit state and the load cases for which a load combination will be automatically generated. Combinations will be generated for each specified limit state.  Automatically generated combinations generally are those required by the code selected using the Design menu > {Type} Design > View/Revise Preferences command.

Note: Automatically generated load combinations are created after one iteration of analysis and design has been performed. Automatically generated load combinations update automatically with each analysis/design iteration; user defined load combinations do not update automatically.

• Limit States for which Automatic Load Combinations are to be Generated and associated check boxes. Specify the limit state(s) for which the combinations are to be generated. When a limit state check box is checked, the program will generate combinations for that limit state.

• Choose Load Cases to Use for Limit State

• • Limit State drop-down list. Limit states are code-specified types of combinations. Choose the Limit State for which combinations will be generated using the load cases specified in the Load Cases for Automatic Load Combinations  list. The list of load combinations must be specified for each Limit State. Note that the  Copy to button (see below) can be used to speed this process.

  • List of Load Cases and Load Cases for Automatic Load Combinations.  All load cases are listed in the List of Load Cases display lists (i.e., Load Case Name, Load Case Type, Design Load Type). The cases to be used in generating the automatic load combination are listed in the Load Cases for Automatic Load Combinations display lists. To specify that a load case be included in or excluded from a combination, select a load case by clicking on it and then use the arrow keys to move the selected load case into or out of the Load Cases for Automatic Load Combinations display lists.

Note:  Each load case has a Design Type that can be set by the user or be program determined. The Design Type of a load case determines if it can be included in a given limit state, how it is to be included (e.g., additive, envelope), and the scale factor to be used, all in accordance with the design code. Only load cases with the appropriate Design Type can be included in a given limit state. For this reason, load cases can not be added arbitrarily to a limit state.

1. 1. • Show Only Load Cases with Valid Design Load Type check box. When this check box is checked, only those load cases with a valid design type for the applied code are listed in the List of Load Cases display lists.

      • Copy to button. Use this button to copy the specified load combination definition to the limit state selected in the drop-down list.  

• • Show Load Case Definition button.

  • 1. Highlight a load case in the List of Load Cases or Load Cases for Automatic Load Combinations display list to enable this button.

    2. Click the button to access the Load Case Data - {Load Case} definition form for the load case selected in Step 1.

    3. The form is provided for review purposes only. Any changes made will be ignored.

  • Set Design Load Type button.

  • 1. Highlight a load case in the List of Load Cases or Load Cases for Automatic Load Combinations display lists to enable this button.

    2. Click the button to access the Design Load type form.

    3. Choose an option to set the Design Load Type of the load case selected in Step 1 to Program Determined  or User Defined. If the User Defined option is selected, choose a load type from the drop-down list to update the load case definition.

Note:  If the Design Type is program determined, the Design Type is inherent in the Load Case type or it is based on the Design Type of the load patterns that have been applied in the load case. The Define menu > Load Patterns command accesses the form needed to specify the Design Type for individual load patterns.