The option allows you to define distances between member cross-sections protected against torsion, that is the lateral buckling length for beams. To access the option:
- Click the icon next to the Lat. Buckling type option,
- Select Element loaded symmetrically in the Lateral Buckling Type dialog,
- Click the Upper flange or Lower flange button in the Member Definition - Parameters dialog, in the Lateral buckling parameters field.
The dialog displays Table 15 from IS 800.
At the bottom of the dialog is the Intermediate bracings option. Select this option and click 
to open the Internal Bracings dialog.