This data table controls how all of the loads are applied to the frame and also enables you to have member self weight loads automatically considered in specified directions.

 

The current list of load combinations comes from ASCE 7-05.  It represents most of the commonly used load combinations suggested for both Allowable Stress Design and Strength Design. This table will be enhanced to provide more controlled specification of load combinations including templates for serviceability checks.

 

Auto-Minimize Combinations to Run

This checkbox instructs the module to eliminate load combinations that have a duplicate set of factored loads or specific combinations that include wind, seismic, earth, and snow load types when none of those load types is present in the model.

 

The purpose is simply to suppress duplicate result sets.

 

Add

This button adds a load combination line to the list. You can then edit the factors.

 

Delete

This button deletes the currently selected load combination from the list.

 

(Load a new load combination set)

This button allow you to retrieve load combination sets from the built-in load combination database and place them in the list. Clicking it will display a popup menu listing the load combination sets currently included in the database.

 

 

 

Description of Items in List

Load Combination Name

This is the name of the load combination. It consists of abbreviations for each included load type along with the associated numeric values that represent the respective load factors. You cannot edit this name. It is constructed automatically based on the entries you make in the following columns.

 

Note in the following image how the Load Combination Name is constructed from the specified values:

 

 

Run LC

Clicking on this entry changes it to a checkbox, which controls whether that load combination is used or ignored.

 

 

This button allows you to change the Run setting for all the load combinations at once using several options.

 

 

Group Multiplier

This value acts as a multiplier on the entire load combination.

 

Lets say your values describe a combination of 1.0D + 0.7L + 0.3E and you want to reduce that entire combined loading by 50%. You would enter a value of 0.5 for the Group Multiplier. The resulting load combination would be 0.50 * (1.0D + 0.7L + 0.3E).

 

Individual Load Factors

Enter the numeric value to be applied to each type of load.

 

Member Self Weight

When either of these two values is non-zero, the module will calculate the weight of each member (as cross sectional area * density * length) and consider that weight during the analysis.

 

A "-1" value for "Global Y" will apply the member self weight downward (in the -Y direction). A value of "1" for "Global X" will have the member self weight applied to the right (the +X direction).