Answer:
You can find this setting in the "Ties and Stirrups" tab of Window 1.6 (see Image 01): under the Defined stirrup spacing option, you can define user-defined distances; for example, 150 mm and 300 mm. Proceed as follows:
- Click the [Defined Stirrup Spacing] button (see Image 02).
- Click the [New] button in the "Defined Stirrup Spacing" dialog box.
- Enter the desired distance in the "New List of Allowable Stirrup Distances" dialog box (0.50 and 1.00 in the example). Then, assign a description to the list; for example, "Only 150 and 300 mm" (see Image 03).
- After clicking OK, your list of stirrup spacings is available for the design (see Image 04).
For the design of the stirrup reinforcement, CONCRETE only uses the allowed distances.