[jws]

The Brooklyn Bridge started construction in 1869. The Bessemer Process for producing steel was the hot, new disruptive technology making large steel bridges feasible. Early mills attempting to use the Bessemer process routinely failed to make quality steel, so there was a level of distrust and high safety margins were well warranted.

Wikipedia has a list of bridge failures curated by inexplicable means. As I scan from the 1800s into the 1900s I see failures of iron bridges, but it isn't until 1907 (a lifetime of engineering after the Brooklyn Bridge) that I see a steel bridge fail during normal conditions, and that is during construction. (Not having a support washed out or a being struck by a steamer.)