Question
When applying 'Assign Floor Loads', [Error] "There is an error in floor load (number = 1). The unit load supporting area (considering sub-beams) should only be composed of 3,4-sided polygons."
Answer 1
If you check the 'Exclude Inner Elem. Of Area', it is possible to assign floor loads.
The reason why the [Error] occurs is that the selected area for applying load is composed of shapes other than triangles and rectangles, or the area is composed of triangles and rectangles, but the range of triangles and rectangles overlaps and conflicts. The first case can be resolved by composing the shapes inside the area with triangles and rectangles, and the second case can be resolved by using following two methods.
The first method is to check the 'Exclude Inner Elem. Of Area' when applying floor loads.
There is a 'Exclude Inner Elem. Of Area' category in the [Load] tab > [Initial Forces/Etc.] group > [Assign Floor Loads].
When this option is checked, the function applys floor loads while neglecting the elements inside the area. This function is useful when you do not want to consider certain elements, such as X-braces, as load-bearing elements.
Answer 2
If you define the X-braces within the area as truss elements, it is possible to apply floor loads.
The second method is to define the X-bracing within the area as truss elements, which enables applying floor loads. Truss elements only receive axial forces, so when assigning floor loads, they are neglected even if they are within the area.