How to do strength calculation on roof truss.

[Håkan3]

Hello.
I have an idea to set up a crane in my barn. I need a structural strength calculation of the truss to see how much load it can withstand.
I would appreciate if someone could help me or direct me where I can turn.
I have attached images and a drawing that shows the truss with measurements, dimensions, and angles.
The drawing shows points A, B, and C, and it is in these points that I want to know how much load they can bear.
Best regards,
Håkan

 

[RiKr]

If this is dimensioned according to today's standards, they are unlikely to hold as they are now, without an overhead crane. If you want a proper opinion, you need to bring in a building engineer to help you.