Metalic stairs problem

Hi guys!
I need a little help.
Plase look at the picture attached.
I need to know if its possoble to design a staits like in the picture.
Im definetly aiming at meatl constuction with maybe wooden tread.
Stairs are going to be “hollow”, not a solid constuction, something like this:

The problem is that I dont have any load bearing walls around the stairs.
Any idea how to design this?

The green portion in the picture defines the passage under the stairs that will have 2,00 clearance under them wich serves as the passage from the room to the closet space.

FOund something here :smiley:

This has nothing to do with Rhino but I am sort of charmed to see physical construction questions make an appearance on this forum.