Question: How to change the effective stiffness of elements? For example, for seismic design according to EC8.

Answer:

Enable the Property modifiers option in the project's functionalities.

In the main menu, within the Structure modeling commands, open the Model data group of commands where you can find the new commands Property modifiers 1D and Property modifiers 2D.

Within these commands, by clicking on the three dots, select the method for modifying the stiffness of elements.

After entering the necessary values, select the elements to which you want to apply these changes.