The most disturbing thing I've read about the Miami bridge collapse so far is the abstract to this paper: https://dspace.mit.edu/handle/1721.1/38943 The oblique references to a collapsed Australian bridge in the news reports are talking about that one.

@mcdemarco oh my.

"The failure of three other box girder bridges between 1969 and 1971...reveal the lack of understanding of the slender compressive elements present in such structures." [dspace.mit.edu]

@33MHz @mcdemarco I hope my gut is wrong and it wasn't corner cutting sub contractors

@EchoDunk @33MHz Inspections are all about catching the corner-cutting subcontractors before the whole thing collapses, so it's unlikely to be entirely caused by missing corners.

@EchoDunk @33MHz My first guess was the novel self-cleaning concrete, but nobody seems to be pointing fingers in that direction.

@33MHz @EchoDunk An interesting theory: https://www.reddit.com/r/StructuralEngineering/comments/84p2vu/fiu_pedestrian_bridge_whilst_under_construction/dvt59ob/