The Amazing Psychic Shannon Revisited

Last August in my post, The Amazing Psychic Shannon, I predicted that the investigation into the Minneapolis bridge collapse would find:

The engineering investigation will reveal the bridge collapsed due primarily to design or construction flaws dating from the time of the bridge’s construction in 1968. Poor maintenance sometime in the bridge’s history will have played a role.

Today we learn that:

Sixteen fractured gusset plates in the center span on Interstate 35W were a main cause of the deadly bridge collapse in Minneapolis last August, the National Transportation Safety Board (NTSB) said on Tuesday. The plates, which connected steel beams in the truss bridge, were roughly half the thickness they should have been because of a design error.

So, I was wrong that maintenance played any role but right that the critical failure arose from a design defect. Still, I amaze myself.

Unlike the case with machines, maintenance plays a relatively minor role in the catastrophic failure of structures like bridges, buildings, levies, dams etc. After all, large structures just have to stand in place. Their major structural elements usually lie deep inside the structure, and usually maintenance simply can’t be done.

The disaster is a good example of how political types milk every tragedy for their own benefit. At the time of the disaster, loud voices were heard proclaiming that the failure resulted from too little state spending on infrastructure, and that the key to preventing future disasters lay in a tax increase. I don’t suppose anybody in the region knows how much the people of Minnesota got squeezed for because somebody made a mistake in 1968?

2 thoughts on “The Amazing Psychic Shannon Revisited”

  1. “After all, large structures just have to stand in place.”

    The three rules of Civil Engineering:

    1. Water flows downhill.

    2. You can’t push with a string (for most values of “string”).

    3. If it moves, it’s broken.

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