Reply #14: The "Joints" Keith keeps talking about are called expansion joints

[Hubert Flottz]

or expansion dams. Expansion joints are part of the bridge deck and not part of the structural steel that holds the bridge up. The workers were replacing the expansion joints and concrete deck on the bridge. They do that to bridges all over the country and it doesn't cause this kind of bridge collapse. I'm betting it was a structural steel failure that brought the bridge down. It looks like the structural steel that connected the arch to the pier on the end of the bridge next to the railroad failed and twisted to the left and started the chain reaction.