Florida bridge collapse shows how Accelerated Bridge Construction can go wrong

This article's premise seems to be jumping the gun — and I question the author's thoroughness in researching it. He links to an article[0] clearly stating that while the design appeared to be a cable-stayed bridge, the tower and cables were in fact cosmetic and the bridge was engineered as a truss bridge. A mere three paragraphs later, he says:

>If a design flaw was responsible, it would be a relatively rare failure of a highly reliable technology. The FIU bridge was to have been cable-stayed, a technology that has been around since at least the 16th century.

I have no evidence that the cause wasn't accelerated bridge construction. But it would be a shame for a promising new technology/philosophy with obvious benefits to become a casualty of this tragedy simply because some commentators couldn't resist rubbing salt in FIU's wound for the irony vaue. It's irresponsible and downright unethical for Slate to publish that claim on pure conjecture.

[0] https://www.usatoday.com/story/news/2018/03/16/miami-bridge-...

The FIU bridge is truss bridge, not a cable-stayed bridge, see this NTSB update [1]. The bridge collapsed because it relied on a single truss with no backup to support the weight if it failed. This created a single point of failure where the collapse of any member (diagonal segment) would collapse the entire bridge.

There is no indication that ACB contributed to this collapse, rather, this was a faulty design that would have also posed a risk using traditional construction techniques.

[1] https://youtu.be/u3Gj1Nu_kjo?t=5m8s

This is silly. We do not know that the overall construction methodology had anything to do with the bridge's collapse. Does the Nipigon River Bridge's collapse show how cable-stayed bridges can go wrong?

The author is a history professor, not an engineer, and it shows with the faffery about metonyms of ecological development in South Florida near the end. If the issue here was with the ABC methodology (as opposed to a misapplication of it), we'll soon learn, but I doubt it. In the mean time, the only person who stands to gain from this FUD is the author.

> Usually in cable-stayed bridges, the towers are built first, and deck slabs incrementally hooked up to the shortest cables. But at FIU, the reverse seems to have happened. Part of the prefabricated concrete deck went up first, and the tower had yet to be added when the collapse occurred.

I had to read that a few times. Is that really what happened. So this is a design where the load is held mostly by the tower(s) and they just laid the bridge down first without the tower and were going to add the tower later.

  In her study of the Challenger Space Shuttle disaster, the 
  sociologist Diane Vaughan noted a phenomenon she called the 
  normalization of deviance, an acceptance of assumptions and 
  shortcuts that over time incrementally piles on risk until, 
  like compounding interest on debt, a kind of technological 
  bill suddenly becomes due.

"Normalization of deviance" is such an amazing turn of phrase to express what it feels like to be involved in accumulating tech debt.