Load combinations can be generated by the program and/or defined by the engineer. Load combinations must be defined before any post-processing can be done.

The load combinations generated and created in this mode are only used where the selected code requires that the "Special (Amplified) Seismic Load Combinations" be applied. For AISC 341-16 and AISC341-10 these Amplified Load Combinations refers to the combinations referenced in Section B2. The ASCE 7-16 and ASCE 7-10 amplified seismic combinations have been provided. In AISC 341-05 these Amplified Load Combinations refers to the combinations referenced in Section 4.1. The ASCE 7-05 amplified seismic combinations have been provided. In AISC 2002 (ANSI341-02) the term "Special Seismic Load Combinations" refers to the combinations referenced in section 4.1, for AISC 1997 they refer to load combinations 4-1 and 4-2, for UBC 1997 LRFD this refers to load combinations 3-7 and 3-8, while for UBC 1997 ASD this refers to load combinations described in section 2213.5.1. It is important to note that a large portion of the checks performed in the Seismic Provision mode use the load combinations defined in the Steel-Standard Provision Mode. The engineer should ensure that the currently selected standard provision load combinations (generated and custom) are appropriate for the checks to be performed in the Seismic Provision mode.

The provisions of AISC 341-05 are written for consistency with load combinations given in ASCE 7 (ASCE 2005) and IBC (ICC 2006). The provisions of AISC 2002 and 1997 are written for consistency with load combinations given in ASCE 7 (ASCE 2002) and IBC (ICC 2000). While AISC 2002 refers to the applicable building code as the source of the load combinations they should be consistent with the codes above to be applicable to the design provisions. Refer to the Section C4 in the commentary of the AISC 2002 specification for more information.

After the Seismic Design Code dialog is closed the Load Combination Generation dialog box appears. This dialog is used to show the "Special Seismic Load Combinations" automatically generated by the program. The combinations generated are based on those load cases previously analyzed and selected in this dialog. The engineer can select to include any or none of the load cases in the generated list of combinations. Click the Apply button after selecting the appropriate load cases to automatically generate and view load combinations in this dialog. After load combinations are generated the engineer can decide which combinations to consider in the design. All rows of load combinations with the "Use" check box selected will be considered during post-processing.

When this dialog is closed the user can return to view or change their combinations by selecting the Combinations > Generate command.

Custom load combinations (where the user can select their own load factors) can be generated in the dialog displayed by selecting Combinations-Custom. Note that combinations created in any other mode are not automatically available in this mode, but must be copied and pasted into the appropriate mode if required.

Once load combinations have been defined and selected, the Process menu commands become available. The Code Check, View/Update and Report commands can then be used as described in the next several sections.