[vtsnowedin]

Cog your last paragraph is spot on. Nobody wants to be found at fault and until the real reason is figured out and announced there will be a lot of sleepless nights for those that made the decisions on the project.

[vtsnowedin]

Latest news cracks were seen and reported but state did not hear the voice mail until after the collapse.
https://www.abcactionnews.com/news/stat ... -voicemail

[vtsnowedin]

$this->bbcode_second_pass_quote('vtsnowedin', 'L')atest news cracks were seen and reported but state did not hear the voice mail until after the collapse.
https://www.abcactionnews.com/news/stat ... -voicemail

[Newfie]

More than once, I as a civilian, have know of issues that resulted in passenger train derailments. One fatal.

I’m not the only one.

[Cog]

The cables on this deck were part of an overall suspension bridge with a pier and overhead cables to support it. The central pier and overhead cables which would support it were not in place at this time and were to be constructed later. The cables they were putting tension on were part of the overall structural strength of the span and allowed them to put this span into place resting on two points. When they attempted to put tension on the span, something snapped which put a shock load on the bridge. Something the designers never anticipated when the allowed a suspension bridge to put into place without the actual suspension part of it being built.

[Newfie]

Are you surmising from past experience or because you have some additional information?

And what do you make of the purported “stress test”?

It strikes me that the design safety limits for the span in question should have been engineered to anticipate such a failure. IMHO once you embark down this installation path the prudent design would have been to assure the first down could stand indefinitely on its own because once in place you can not guarantee the remaining work will be completed. All kinds of unexpected things can happen to shut a project.

Now you could design it to be placed and not occupied until completed, thus limiting the load. But to put in place over an active highway? No. I think you explanation is reasonable were it over an unoccupied space.

[Cog]

There was no stress test Newfie. The cables they were putting tension on were part of an overall suspension bridge. Internal cables, within the bridge deck, without the overhead suspension, were being tightened so that the deck could rest on two points. The main pier and overhead suspension cables were not in place and would be constructed later.

What they did was to subject a suspension bridge to an unexpected shock load(when either the cable failed or the crane failed) without the actual suspension part of the bridge in place. Its not wonder that it failed.

[Cog]

This is what the bridge was supposed to look like upon completion. That main pier with the overhead cables were not in place when it collapsed.

[Cog]

Anchor points for overhead cables that would be constructed at a later point in time.

[vtsnowedin]

Well that adds more mystery to it. Modern cranes have a load cell between the cable end and the hook ball that reports back to the operator and the crain's computer. The operator knows at all times the load he is applying and the crane will lock out if load limits or boom angle limits are reached.

[Newfie]

Thanks COG. Seeing that model is very helpful.

So news reporting on “stress test” is bogus.

Still doesn’t explain why they would do this.

[vtsnowedin]

I wonder if they are wishing they had put a temporary pier on that chevroned center lane to support the span while they completed the tower and cable stays?

[jedrider]

An Innovative Signature Bridge
http://www.miamiherald.com/news/local/article205661039.html

Here's some more information and a nice picture of what the bridge would have looked like finished.

I tell you, the design seems strange to me! Especially, the comment that the bridge was DESIGNED to stand without the overhead cables AND center column. So, I ask you, 'What holds it up?'

[dolanbaker]

A video of the collapse has also emerged, clearly showing a mid span failure.
http://www.dumpert.nl/mediabase/7389671 ... miami.html

[vtsnowedin]

A meeting about the crack was held two hours before the collapse. I'll bet pictures exist.
https://www.huffingtonpost.com/entry/fl ... 2217ff43ea

[Newfie]

I can’t watch videos, can barely post most times. Pisser.

Cog, I looked at you post above once again, I had not expanded the pic and read the entire caption.

It does state they were doing a “stress test” when it failed. I had not realized they were using a crane to put a load on these anchor points.

The pic and caption bring up more points to me, many questions. I won’t pester you with them. I’ll just leave it at saying the whilole plan seems idiotic and ill conceived to me.

I should not be shocked. I’ve seen too many blunders in my career. One of the best was a Math PhD candidate who was responsible for some simple installation drawings. Unfortunately he was under my charge as I was sealing the design, even though we worked in different cities. I went to his office and found him pouring over the drawings, editing them he said. I was giving him a hard time about his drawings, at this instant about the gibberish/ghetto slang in the Notes. He was defending the notes staunchly. I demanded read that “stuff” (well, it started with “S”) and he said he could not, he had left his glasses home. WTF! Then how can you edit drawings? And why are you arguing with me? This same guy gave a supplier written permission to provide cable that clearly did not meet tunnel fire code specs. Something like 7 miles of it. He also produced drawings with 2 North arrows, pointing different directions. Etc.

No one else in the company was phased by his performance. He was a “good guy”. Tall, slim, good looking affable, good line of “stuff.” He ticked all the boxes for a “company man.” I managed to drive him out of the company at some personal expense. You may find it hard to believe but I’m not always affable.

And I could go on. But I won’t, I’m sure you and VT and others have war stories of your own.

The point is, from my perspective, I’m can see this kind of thing happening. Thank God I never got caught in one of these blame games. I guess it’s a sore spot for me.

[vtsnowedin]

$this->bbcode_second_pass_quote('Newfie', 'Y')ou may find it hard to believe but I’m not always affable.

[Subjectivist]

Vehicle dash cam footage of the actual collapse as it happened.

https://youtu.be/Ucflj-MsJBI

[vtsnowedin]

$this->bbcode_second_pass_quote('Subjectivist', 'V')ehicle dash cam footage of the actual collapse as it happened.

https://youtu.be/Ucflj-MsJBI

[Newfie]

Ah ha, I was able to view that video. Thanks for posting.

A couple of observations:

That’s not a real big crane

The Workman (poor soul) appeared to be leaning over the anchor point. I doubt he would be leaning over that point while strain was applied. Very bad practice.

When the structure breaks I don’t see the crane jerk back or otherwise move. So I don’t think there was any stress on the crane at that instant.