Determining the forces in a framework

[question dude]

The framework is attached below. I've tried going to each joint and resolving the forces vertically and horizontally. I've got to joint B and I'm stuck, because I have three unknown members there. And its the same if I go to joint J.

what do I do?

 

[paisiello2]

I don't see a joint J.

Can you set up 2 equations at 4 joints and solve for 8 unknowns?

 

[pongo38]

You are stuck because the frame is statically indeterminate. This means that the equations of statics alone are insufficent to solve for the member forces. If you want to proceed you have to introduce another equation related to the member properties AE. There are a number of different approaches to this, including use of Castigliano's theorems. That is what I suggest you look up.