Got it sorted and yes, it was the prolonged time I had been working on the scene that caused the crash while doing the physics calcs. Ran smooth with a reload.

I need to redo that floor texture again, less warped more broken bricks. I also need to reredistribute my brick piles. I had to move them so they weren't making contact with the bridge before dropping them. I also need to work on a transmap for the right hand bridge section, right now I just have the textures turned off and you can see gaps in the pylons.