who want you do that?
for the building permit? you need an architect prepare the drawing, and stamp it.
like a small workshop, if it is attached to the house, the architect shall can do it, but you looks like looking for an Professional Engineer for structure design, or at least a geo engineer to do your job. this a huge responsibility, you may need go to an opened company with insurance to do it for you, and pay for it.
I am licensedP.Eng., but no one will do this thing without knowing that area, and without insurance, and stamp on it.