Screenshot shows it all. The Masonry bridge is accidently using the Masonry viaduct winter graphics resulting in... certainly not a bridge I would walk over.
Once the snow melts it looks all safe and stable again.
This applies to the ramps as well. Not seen in the screenshot as the snow line happened to be above them in this case.
Thank you for the report; I think that I have now fixed this. I should be grateful if you could confirm whether this is fixed with the next nightly build.
Appears fixed now. No more bridges that shrink when cold!