I am not convinced by that bridge. I'd need to know more.
I always detested TCD's pedestrian bridge across Westland Row. Clealy it is a bridge which was supported by the piers at either side of the road, i.e. a beam bridge. But it also includes a curved section which gives the impression that it may be an arch bridge. What annoys me about that bridge is that Westland Row is narrow enough that it should be reasonably easy to build either a beam bridge across it or
an arch bridge across it. However, it shouldn't be necessary to require both forms in the same bridge to traverse the street.
Every time I see it, it simply cries out "crap engineering" to me.
I suspect that the same thing may be going on here. The old bridge at the dock was a drawbridge. I suspect, though I may be wrong, that the new one is a simple beam bridge. In which case, the arch actually has no function.
Until I know more, this bridge will be saying "unnecessary window dressing" to me.