Third Avenue Bridge, which connects New York’s the Bronx to Manhattan, got stuck in an open position due to the high heat on Monday.
FDNY officers arrived in boats and fired water at the structure to try and cool down the metal, which expanded after high temperatures in the city, officials say.
The incident caused major traffic delays during one of the hottest days of the year in New York but reopened on the same day.
This bridge was probably also designed to account for thermal expansion to a certain degree. It seems like more and more of our infrastructure is starting to fail, encountering heat levels it was never expected to encounter. I wonder if failures like this and worse are going to become a common headline
Bridge engineer here (not much experience, so I wouldn’t consider myself an expert, but I have more knowledge about it than the general public).
Your suspicions are correct, bridges are designed for thermal expansion. More of our infrastructure is starting to fail, and part of that is because it’s experiencing climate it was never designed for (heat, sea level rise, more drastic storm surges, etc). I would fully expect this to be a more common headline. At least for several more years, anyway. If the federal money from the infrastructure bill the US passed a few years ago runs out or is not allocated to the right structures, then this will only get more common. I don’t expect the Trump administration to champion an extension of these funds if they do run out. It was passed under Biden, after all.
As for this bridge in particular, this is a moveable steel bridge. The fact that it’s moveable means it is particularly sensitive to expansion (as well as salinity which causes rusting). Too much expansion, and the steel will get stuck in one position. In a typical steel bridge, if the thermal expansion exceeds what it was designed for, you end up getting higher stress levels in the steel as it pushes harder against the abutments. Usually this is alright in the short term, since we design these to withstand much higher stresses than it will ever likely experience. Repeated cycles of this, however, will cause fatigue failure (think of a paperclip or metal spoon snapping after you bend it back and forth a bunch).
Anyways, there you have it. I rambled for too long about this lol.
I rambled for too long about this lol.
The fuck you did! Making the world a little less dumb, one ramble at a time, is a good thing. We don’t all need to be specialists in everything, but a brief summary like this contributes to our general knowledge and is a net positive.
Do you have a favourite bridge?
Edit: I don’t know many bridges, but I quite like the Millennium Bridge in Gateshead. (https://en.m.wikipedia.org/wiki/Gateshead_Millennium_Bridge) My dad took me and my siblings there when it opened. It was a big deal for the area and I was young enough to not understand why, so I looked at it real hard to try to understand why everyone was so hyped. I concluded that it was a pretty good bridge.
