M. To apply a dynamic wind load per SP 20.13330.2016

To apply a SP 20.13330.2016 wind definition as a dynamic load to your structure, use the following procedure.

A modal analysis and at least one static load cases are required in order to use a dynamic wind load case.

In order to perform dynamic wind load generation in STAAD.Pro you must previously define a static load case. The static load case could be any primary static load case which is defined before the Russian dynamic load case, including a static wind loading per the same code. This static load case will provide static load vector to the dynamic wind load module.

As the Russian dynamic wind load component requires modal masses and eigen vectors to calculate the dynamic wind load component at nodes, modal analysis must be performed before the dynamic wind load definition. Therefore, you must also include a separate load case for modal analysis with reference mass defined before the load case. See G.17.3.2 Mass Modeling for details. Alternatively, if the mass loads are not needed for use with other load cases (that is, a reference load case is not needed for other loads), then you may define the mass loads within the dynamic load case prior to the WIND LOAD command.

Either:

On the Loading ribbon tab, select the Load Items tool in the Loading Specifications group
Tip: This will add the load item to the currently selected load group selected in the program status bar.

or
In the Load & Definition dialog, select a primary load case in the Load Cases Details list and then click Add.

The Add New Load Items dialog opens.
Select the Wind Load > Wind Load - Dyanmic tab.
Note: If you have not previously added a SP 20.13330.2016 wind load definition to the model, this tab is inactive. Refer to M. To add a SNiP wind load definition for details.
In the Select Type drop-down list, select the wind load definition for this load case. Only SP 20.13330.2016 wind definitions are present in this list.
Type the Width of building along wind dir. and Width of building across wind dir. values. These are the width parallel and perpendicular to the wind direction, respectively.
Type the load Factor value.
(Optional) Check the Allow All Mode Shapes to include all mode shapes from the modal analysis. Otherwise, only the first mode shape will be used.
Select the Static Wind Case from the drop-down list of primary load cases that precede this load case in the model.
Select the direction in which the wind is applied from the graphical plan view.
Click Add.