To specify elevator openings

Since the analysis model does not contain openings in the slab, you can add those in RCDC.

Note: RCDC can design and detail concrete stairs with the slab. Do not create an opening for the stairs if you plan to use this feature. Refer to the RCDC help topic Slab > Staircase Section for details on this feature.

In the Design Data table, select row 19 (for Slab 18). The slab is highlighted in the Slab Layout view window.
Do either of the following:

select True in the Is Cut Out cell for this row in the table

or
right-click on the slab in the view window and select True from the Is Cut Out drop-down in the pop-up menu

The slab is now marked as a cutout.
Select Modify > Re-evaluate Slab continuity.
Note: This will change the continuity of surrounding slabs. If you do not perform this step, you will be prompted to automatically re-evaluate the continuity before performing an autodesign.