Hi All, 

This is my first question so I'm not sure who will see it/be able to help but here goes. 

Basically I'm doing a project for uni where I have to propose alternate load paths around critical truss joints, so if the joint fails the stress can redistribute (I'm using the I-35W bridge collapse as a case study, for anyone interested). I don't have to use FEA software to do this, but I'd really like to so I've been having a go. The below image is a first attempt at the 3D model with some generic cross sections and forces applied. 

What I would really like to do is simulate the failure of one of the top joints, then add some members around that joint and simulate failure again to see how the stress redistributes. My question is: what is the best way to achieve this? I've tried adding the extra beams and deleting the mesh around the joint, which seems to give a reasonable output, but I'm sure I'm overcomplicating things.

If anyone can offer any help or advice on this I'd really appreciate it, I've got a couple of weeks to get this right...

Regards

Rob