..if you divide truss in seperate elements when modeling with slab, than you will be able to adjust texture direction for each one. Than group all and save as an object and you will be good.
Do you use combination of yellowish and bluish lights? It is too much yellow (unless you are aiming for sunset mood). Last thing - it might be inverted bumping in stone wall shader, or maybe just too weak
Keep posting, I'd like to see when you can get.