The custom load combination dialog is displayed by selecting the Combinations-Custom command.

The load factors should be normalized such that for all load combinations the allowable interaction equation value is 1.0. For example, as explained for Generated Load Combinations, the allowable stresses for ASD can be increased by 1/3 for wind and seismic loads. This should be handled in the custom load combinations by assigning factors of 0.75 rather than 1.0 (i.e., the loads are factored down rather than the allowable stresses being factored up).

Separate combinations of plus and minus factors should be created where appropriate; the program does not automatically reverse the signs of the factors on lateral load cases for user-specified custom load combinations.

Refer to the Load Combination Generator Manual for more information about custom load combinations.