hey, i'm a person who owns a 3D printer and knows a quite a bit about them

1. this guy has maybe heard of 3d printing and maybe has read an article, that's about it
2. there is absolutely no fucking way to make a printer for this - it would have to be steel+cement multi material, and you can already forget about ever doing that. the printers for steel and cement are completely and inherently different, and I don't think they even make steel printers larger than roughly the size that would fit in a corner of a workshop/lab, only cement printers are made for large industrial tasks like housebuilding. not to mention how difficult and costly steel printing is
3. even if such a god printer did hypothetical, the bridge would be so ungodly expensive to fabricate and would take so long and there would be so many places for shit to go completely wrong that it would be entirely pointless and dangerous to use 3d printing for the job, you would just be better off building the fucking thing.

maybe in the future it might be possible but in the present this guy has directly connected his asshole to his mouth