[bamboozled]

I remember visiting Amsterdam in a heatwave, maybe 2016, and they were hosing the canal bridges off to cool them so they'd close properly.

Apparently they'd expanded from the heat more than they were designed to cope with.

[xxpor]

That happens in Seattle too. I'm surprised the metal expands that much myself.

[aidenn0]

The expansion is as a fraction of length. For steel its around 10-20ppm per degree C.

So a 40 degree temperature swing would be 400-800ppm, which means about 1mm difference in length for 2m of steel. Obviously bridges aren't usually made of a single span of steel, but there will be limits to how much expansion a given joint can tolerate, and each half of a draw-bridge needs to be fairly rigid. On top of that, 40 degrees is probably much less than the difference in road temperature between a cold night in January vs. a sunny day in August.

Railway tracks used to buckle in the heat before they built them with a small gap between the rail spans.