Engineers really know their stuff

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warmstrong1955
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Re: Engineers really know their stuff

Post by warmstrong1955 » Wed Mar 21, 2018 7:38 pm

I have weird hobbies..... :) can't help myself. Hereditary thing.....I have numbers from the Hyatt Regency walkway collapse that my dad did after that happened.
Most of my career was spent finding out why things break, and broke, and fixin' 'em so they didn't again.

I would guess there's about 500 college boys crunchin' numbers, testing concrete & steel samples, re-crunching numbers, and generally re-creating the entire mess including with a blank piece of paper....or I guess....a blank computer screen... ;)
Finite Element is on overtime....
Assuming the original design, to spot a suspension bridge without the suspension, has enough of a safety factor to stay put till the pylon & cables are installed, there's a whole list of other factors that involved.
And if I worked for the engineering company that designed it, or the construction company that was building it....I'd be awful nervous. Besides....both are companies with less than stellar records. Maybe that's a typical Miami thing? Pick the low ball bidder, ignoring their track record?

Again....just my opinion. I think it will be multiple errors, and maybe some construction errors past engineering...along with a bad decision to re-tension, or what they have been calling, a 'stress test'.
Some test.

Bill
Today's solutions are tomorrow's problems.

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SteveHGraham
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Re: Engineers really know their stuff

Post by SteveHGraham » Wed Mar 21, 2018 7:44 pm

AvE has a very informative video which pretty much backs up warmstrong's take, as well as my opinion of Miami construction. I am no engineer, but I am gratified to see that he shares my feeling about letting a guy adjust a bridge while traffic is moving under it. Total Miami move.

He also questions whether it was supported correctly. Evidently, some changes were made, and the doodads that held the bridge up were moved to new positions.

Every hard-fried egg began life sunny-side up.

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warmstrong1955
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Re: Engineers really know their stuff

Post by warmstrong1955 » Wed Mar 21, 2018 8:12 pm

:lol: :lol: :lol: I'm still laughing!
I've worked for four different Canadian companies. If you only knew how many people that guy reminds me of, and I'm talkin' CEO's, presidents, managers, and engineers on down.
Made my day!

He has a few other ideas besides mine, and better detail, in spite if the language, but I can't argue with any of 'em. It is pretty much the same as what I surmised.

If you want to look at the drawings he has, guess I should have posted them already, they are here: https://facilities.fiu.edu/projects/BT_ ... 0-2015.pdf
Not enough detail to crunch numbers, but it'll give you the general design. GA drawings of the bridge start at page 100.

Thanks for the vid Steve!
I got a couple of Canadian buddies I'm going to forward that to! (Soon as I can get back on my chair)

:)
Bill
Today's solutions are tomorrow's problems.

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SteveHGraham
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Re: Engineers really know their stuff

Post by SteveHGraham » Wed Mar 21, 2018 8:51 pm

I can't stand that guy's conversation. He's so filthy, he's like me in college.
Every hard-fried egg began life sunny-side up.

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BigDumbDinosaur
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Re: Engineers really know their stuff

Post by BigDumbDinosaur » Wed Mar 21, 2018 10:45 pm

SteveHGraham wrote:
Wed Mar 21, 2018 7:18 pm
Construction is generally pretty bad in Miami...use illegal labor...
Hmmm...I sad something about two words earlier. :D Perhaps this bridge project was...oh, never mind. :o
Science makes it known. Engineering makes it work.

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NP317
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Re: Engineers really know their stuff

Post by NP317 » Wed Mar 21, 2018 10:54 pm

Yes, interesting analysis.
I may have done more comprehensive strength calculations on my two locomotive boilers than might have been done on the construction changes made in that bridge design.
Sad.
~RN

tornitore45
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Re: Engineers really know their stuff

Post by tornitore45 » Thu Mar 22, 2018 5:40 am

I think that it might be just barely possible that a machinist also once made a mistake.
Or a lawyer.
Mauro Gaetano
in Austin TX

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warmstrong1955
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Re: Engineers really know their stuff

Post by warmstrong1955 » Thu Mar 22, 2018 7:24 am

NP317 wrote:
Wed Mar 21, 2018 10:54 pm
Yes, interesting analysis.
I may have done more comprehensive strength calculations on my two locomotive boilers than might have been done on the construction changes made in that bridge design.
Sad.
~RN
I think the changes had a lot to do with it. It got 11' wider on the section across the road. Request of the Florida DOT, so they could add another lane in the future. That change, also changed how it was lifted, and moved to place it.
Whether that caused the cracks an engineer saw, and then why they decided to re-tension....remains to be answered.

If you look at the Hyatt Regency walkway failure, the original design was sound. It was an 'approved' change, that happened after it was designed, to make it easier to install.
They crunched the numbers on the original design, who knows how many times. The change....some one or some people shot from the hip.
Whoops.

Bill
Today's solutions are tomorrow's problems.

John Hasler
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Re: Engineers really know their stuff

Post by John Hasler » Thu Mar 22, 2018 8:30 am

Bill writes:
> I think the changes had a lot to do with it. It got 11' wider on the section across the road.
> Request of the Florida DOT, so they could add another lane in the future.
> That change, also changed how it was lifted, and moved to place it.

While the design change obviously would have gone through the full change-order process, the changes in the installation process may not have as they were changes in the contractor's methods that would not have resulted in any change in the completed bridge. They still would have been approved by the prime contractor's engineers, of course.

It's also possible that a request to close the road was made but of course that would have had to go through channels at city hall.

(I stress the "may". I'm just speculating, of course.)

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warmstrong1955
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Re: Engineers really know their stuff

Post by warmstrong1955 » Thu Mar 22, 2018 8:42 am

Did it go through a full change order process?
Should have, but did it? They were $2,000,000 over budget.
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John Hasler
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Re: Engineers really know their stuff

Post by John Hasler » Thu Mar 22, 2018 10:04 am

I don't see how it could not have as it would have required a substantial cost increase.

Was this a design-build contract?

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warmstrong1955
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Re: Engineers really know their stuff

Post by warmstrong1955 » Thu Mar 22, 2018 10:34 am

I'm not sure what the contract is. I have read it was $9.3 million when it was awarded....then $14.2 million. I haven't really followed the money. I spent more time trying to find at least some GA drawings, to see how it was supposed to be built.

I've seen too many times, that people will blow things off, when they make a change. Luckily, the changes I was around only caused things like equipment frames to crack, hydraulic cylinders to self destruct, and drivelines to fly to pieces. Downtime, but not folks getting hurt.
Again, the Hyatt Regency walkway was a prime example. The construction company wanted the change to make it easier to build, the engineering company did it, and we find out later....they did not crunch the numbers. If they would have, they would not have made the change.
Not saying that's what happened with the bridge, just that it's in the realm of possibilities.
Today's solutions are tomorrow's problems.

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