If you do retake these, I would agree try for the "symmetry element". In this one it would have been better,( my opinion) if you had arranged for the centre support on the bridge to somehow bisect the sunset. Even if you were to arrange to have the centre support of the bridge in the centre of the image, the fact that the sunset is off centre stills takes away from the overall symmetry - make sense? Personally, I would concentrate on having the sunset in the centre with the bridge span, rather than the support, acting as a bit of a frame. My 0.02¢ FWIW.
WesternGuy