Investigators Explain Focus On Pre-Collapse Cracking In Florida Bridge

Engineering News Review ^ | May 24, 2018

[PAR35]

It’s politics overriding competence.

An early example was HMS Captain(1870), but back then they called it a ‘vocal but ignorant clamor’

Earlier than that - the Vasa 1628.

[WhoisAlanGreenspan?]

In many cases working or machining steel cold is better than hot, steel follows a grain that cold forging (forcing the steel to follow) produces a stronger result than heating it.

You and probably everybody reading this already knew that however.

[Right Wing Assault]

I thought the Hyatt walkways had a sufficient design, but it was difficult to run the nuts up the threaded rod, so the construction people cut the rods at each floor. Therefore, two rods and next to each other, one not on the top of the concrete, the other nut below. This put a bending load on the concrete. When the people started dancing, the concrete cracked and that was the beginning of the end. People heard the cracking before it went down.

Yes, corrosion led to the Minnesota failure, but a lot of corroded bridges don't fail. There was component that was crucial. No redundancy. If it any of those failed, the bridge fell. Bad design.

[Moonman62]

All three human tragedies at NASA were the result of management failures.

Apollo 1
Challenger
Columbia

[tet68]

There are steels like that, it’s one of the amazing
things about Ferrous metallurgy that so many properties
can be brought about in the different working methods.

Most people today do not think about how their life
would be without iron or steel. It would be harsh.

I’ve been a blacksmith metal worker for over 45 years,
forge, foundry, red Iron, special fabrication.

[packrat35]

https://en.wikipedia.org/wiki/Hyatt_Regency_walkway_collapse

[generally]

Thanks for the info.

Sounds like you were doing a tough job. Shortage of men who can handle that these days.

[KC Burke]

thought the Hyatt walkways had a sufficient design, but it was difficult to run the nuts up the threaded rod, so the construction people cut the rods at each floor. Therefore, two rods and next to each other, one not on the top of the concrete, the other nut below.

I was very involved with many people in the skywalks collapse. I knew Havens Steel and their founder, Fred Havens who was a friend of my dad's. I knew the attorney named the Special Master by the Courts to settle all claims after the trials and the Fire Captain who had to do an amputation with a chain saw was my neighbor.

The Jack D. Gillum and Associates Engineers out of St. Louis made a flawed design that was understrength even as originally drawn. (They were not a minority firm). Havens Steel detailers knew that you couldn't thread nuts up four stories as you tried to erect this thing and the stupid framing the nuts held were channels welded flange to flange to make a jury rigged box beam. They submitted a shop drawing showing the staggered rods giving the engineers reviewing it a chance to correct the idiocy and they did not.

An old steel erector I worked with as a kid stepped off the walkway with his wife five seconds before it went down.

[Calvin Locke]

[Hyatt]... one not [nut] on the top of the concrete, the other nut below. This put a bending load on the concrete.

Once the contractor-induced failure point was id'd, the point of failure were the bottom nuts supporting the top walk. That is, it was designed to support one walkway/traffic, and with the cutting of the threaded rod, it then was supporting the weight of the walk/traffic below, as well, since by extension, the top nuts of the bottom rods were pulling on the top walkway's bottom nuts.

If the job had been done to spec, there would have been only bottom support nuts supporting only one walk, not effectively two walks.

You can blame the architect/engineer for making it a PITA to install correctly, but the contractor didn't do the job to spec to save time-money, not to mention repetitive motion injury claims...

[PAR35]

The original design for the walkways was good. The contractor wanted to do something different, and an incompetent and/or lazy engineer approved the change without bothering to do the needed work.

As for the bridge, the heavy construction equipment and the concrete barriers overloaded the span, corroded or not. Again, someone was either not competent or too lazy to do math.

[logi_cal869]

It was also improperly supported with the detensioned cables...a major contributing factor to structural failure.

[Right Wing Assault]

Again, someone was either not competent or too lazy to do math.

Yes. My favorite lazy words, "It should work," spoken by the lazy after I had said, "Did you try it or check it."

I knew a high school kid who had twelve 'It-should-work' failures in three days. I hope that cured him.

[PAR35]

I knew a high school kid who had twelve 'It-should-work' failures in three days. I hope that cured him.

As long as it doesn't provide an undue risk of permanent harm, it's good for a high schooler to learn through experience. A professional engineer who puts lives on the line through such conduct - life in a maximum security prison might be appropriate.

And if it turns out the problem was that the engineer didn't know what he didn't know, then a whole bunch of other folks responsible for that state of affairs should be rounded up, as well.