To add a response spectrum load case

To add a load case for your response spectrum load, use the following procedure.

Response spectra can not be used with a load group. Only load cases have the option for the response spectrum category.

On the Model ribbon tab, select the Load Case tool in the Loads group.

The Add Load Case dialog opens.
Type a unique Name for the load case. This is helpful in identifying the load case.
(Optional) Type a Description for the load case.
Select Response Spectrum from the Category drop-down list.
Select the response spectrum definition from the Parameter Set drop-down list.
Specify the Direction in which the load acts by typing factors in one or more of the X, Y, and Z global direction fields.
Click OK. The load case is created and selected as the current load case.

Note: No loads are graphically displayed for static seismic or response spectrum load cases.

You may repeat this procedure to add additional load cases applying the response spectrum definition in another direction or to use a different response spectrum definition.

Response spectrum load case details can be viewed and edited by selecting the Response Spectrum Load Cases tool in the Reference group on the Spreadsheet ribbon tab.