Wonderful, imposing shot you've done here. At first glance, I almost thought it was a live version of a Beksinski painting. That probably has a lot to do with your color choices here, as much as anything. I think the yellow and green work very well together.
I believe you made the right choice in the square crop, although, as I stare at it more, the trees on the right side are slightly out of place compared to the foggy, shadowed background. Also, and it may just be me, but there seems to be some slight curving starting about halfway up the pillars, no doubt due to perspective. Maybe a little Straighten Tool in Photoshop or Lightroom can fix it, though it's not noticeable enough to be distracting to non-photographers.
Again, a really wonderful piece of what would normally be a common subject. Keep up the good work.
I agree that the square crop was a great choice. It really help to elongate the bridge. I like the color choice. The subtly of the pallet really helps to give the image a certain mood. To me, it feels a somewhat stark and overwhelming. The structure of the bridge becomes almost otherworldly with the pink foggy sky behind it. The pink fog has a really nice interaction with teh green support system of the bridge. The colors work well together, and don't try to dominate each other. The composition really helps attract attention to both the bridge and the structure beneath it. The interaction between the two helps give the image a certain amount of tension that really works well within the frame. Overall Amazing!