To add a time history nodal load

To apply a force or moment time history load to a selection of nodes, use the following procedure.

You must have created a time history load definition using either force or moment data and a time history load case.

Time history nodal loads can be applied to any node, including supports.

On the View ribbon tab, set the active Load to a time history load case in the Active Load group.
Select the nodes to which the same time history loads are to be applied.
On the Node ribbon tab, select the Time History Load in the Time History Loads group.

The Add Time History Load dialog opens.
Select a time history load cases from the Load drop-down list.
Select either an force or moment time history definition from the Definition drop-down list.
Type a Start time with respect to the time history definition the ground motion begins.
Type an acceleration amplification. Factor to use for the load.
Select the global Direction in which the load is applied.
Click OK.

You can edit time history nodal loads for the current load case by selecting the Time History Nodal Forces tool in the Node group on the Spreadsheet ribbon tab.