For the seismic analysis of the structure, the program allows concrete structural beams to be designated as primary beams or secondary beams for the purposes of their performance in the earthquake-resistant system.

To do this, use the "Earthquake-resistant category" option in the "Beam input" tab in the "Beams > Other options" menu.

In the dialogue box that appears, select one of the following options:

• Primary beams against seismic action
• Secondary beams against seismic action

The "Assign" button allows you to select the beams to which the selected condition will be applied one by one, while "Assign to all" applies the selected condition to all concrete beams on the floor. The "Finish" option closes the dialogue box.

The program uses a colour code to indicate the condition assigned to the different concrete beams on the floor plan.

Secondary elements in relation to seismic action are structural elements that are not considered part of the building's resistant system for withstanding such seismic actions. Therefore, these elements do not need to meet any special requirements.

The stiffness of secondary beams for seismic scenarios is reduced according to the value defined in the "Inertia reduction factors" dialogue box (under the "Project > General options" menu). The mass of secondary beams will be taken into account.

With regard to capacity checks, the designer can indicate how they wish to consider secondary beams according to their judgement in the dialogue "Secondary beams under seismic action" (within the menu "Structure > General data > By position (steel bar calculation options) > Beam options > Design/Check").