Apparently people peeing on steel objects is an actual serious structural issue.

Here's a bridge in Sumatra that got hit:

https://www.loosewireblog.com/2004/11/urine_corrosion.html

the 1,177-meter long and 22-meter wide bridge

Last Friday, The Jakarta Post carried a story headlined “Bridge in Palembang may collapse due to excessive urination”. Not really much more needs to be said, but let’s spell it out. The bridge is sloping. This ‘irregular slant’ had been confirmed by Professor Annas Ali, a highway and bridge expert at the public works office who conducted research on the bridge recently (presumably by standing on it and noticing that he was not standing, as we engineers call it, ‘straight’).

Upon further inspection officials noted that, in the words of the Post, “one of the reasons for the apparent structural deterioration was due to the frequency of people urinating on one of the steel pillars of the bridge, causing it weaken due to the corrosive forces of human urine.” This deterioration can be measured since you can actually feel the bridge ‘resonating’. This was proven by the head of the city’s transportation office, Syaidina Ali, who advised the Post reporter to ”try standing on the Ampera bridge. If the traffic passing on the bridge is heavy, you can feel it moving quite a bit.”

I see another reference to civil engineering proceedings on a bridge in the Carribbean that faced a similar problem.