Here is the number

showcrop

Well-known Member
Time magazine on line reported last night about a voicemail from the bridge construction company to the Florida DOT Denny Pate with FIGG left a voicemail with the Florida DOT about some cracking in the bridge. But they saw "no issue from a safety perspective". The Florida DOT will of course be investigating this, so they will need input from the YT bridge experts about all of their knowledge about what happened. The Miami area secretary is Jim Wolfe and his number is 800-435-2368. So everyone with positive knowledge needs to call.
 
When you get a call about cracks in a concrete structure, shouldn't
you get your rear in gear and go take a look? If that prestress was
not done correctly with the embedded steel cables that were not
stressed or not tight enough. Looks very much the same as the sections
used in parking garages. Could have been crappy concrete. Remember the
Challenger. Morton Thiokol engineeres told them that 22 degree weather
was too cold and the "O" rings would shrink. NASA wanted to keep on
schedule. Most Engineers are very good but the upper people rule. So
kany times I have seen wher people have a fealing in their gut about
something. They get over ruled by some bozo and there ya go .
 
Was this cable pulled through concrete prestressed?

well, either the cable or the concrete gave out.

The stress of moving it was much harder than typical build in place, and so the weakness showed up right quick, instead of 20 years down the
road.

Will be pretty easy to sort it out. Designed with a weak spot, or built with weak materials, or assembled wrong, it will be one of those and easy
to figure. Of course all three will point to each other, but if the right folk get to look over the specs and rubble nothing will hide.

I will guess the design wasn't strong enough for the move, something flexed more than the designer thought of. But that flaw showed up
because something else wasn't up to par. Weak batch of concrete, or bad cable ends, or the fellas didn't tighten the cables right.

Almost always takes 2 mistakes for something like this to show up. Everyone over engineers enough to deal with one bad issue.

Sad for the people involved.

Same company built the new bridge in Minneapolis, to replace the one that collapsed a few years ago. So, hummmm. The old bridge that
collapsed had the wrong gussets, they were only 1/2 as thick as they should have been. Too weak. But the bridge stood for decades no
problem. Until salt eroded some metal, and they did construction on top of the bridge and the crew piled material very heavy in one spot on the
bridge deck.... so it took 3 issues to bring that bridge down. Bracing was too thin, salt corrosion, and overloaded point load.

Wonder how well they designed and built the new replacement bridge? It was designed and built in a hurry.

Paul
 
Head of A.S.C.E. stated the obvious only on the news, did the concrete go the 28 days to reach design strength, and integrity of materials used to fabricate this bridge. I'd imagine going into any further detail in front of a microphone was intentionally avoided.

With this method of construction being new and the amount of engineering involved, there has to be a plethora of concrete test cylinders and results from breaking same. Same with other controlled inspections on other materials.

Cut and dry on placing this span over a highway without stopping traffic. That just has to violate the remotest of common sense of the lowest forms of life on this earth, why they would even consider it is beyond me. It's impressive that technology exists to make it possible to shorten the duration of bridge construction so much. Looks like those overseeing got a little greedy in thinking they can erect such a behemoth and not interrupt traffic.
 
Hadn't looked at that thread, since you seem to have a wedgie about it, I read through it.

Folks always speculate about a failure, until we get actual results, folks are going to ponder on it.

I was wondering about the odd angles in the middle supports when I saw pictures they didn't make structural sense; now I see - this was going to be a suspension bridge. So all those off center angle pieces along the middle make sense when it's done,, but don't support well without the top cables.

So:

They built 2/3 of the bridge, the middle backbone.

And hauled it into place on two large jacks, supporting it from below 1/3, 2/3, 1/3 sagging load and expanding itself.

They hung it there, and supported it from the ends. There may or may not have been a temp middle support too? So it was now a sagging load, but supported from 2 or 3 totally different different pressure points. Still in expansion.

Then, the plan was to put the real middle support in, and run cables, and support the bridge from multiple cables. So supported from multiple vertical compression points. And compressing itself.

So........

They had to design this hunk of concrete to take the stress of:

moving.

And supporting itself in -two different- bottom lift configurations no compression; and then eventually stand for decades with live loads in a suspended, compression design.

Wow!

That thing had to be designed for 4 different load points and stresses. Bottom support and top hung are totally opposed to each other when building with concrete, very goofy to try to do that with a long skinny piece of concrete. Some city council got their fingers into the plans and 'wouldn't this be cool' and made it the mess it is.

Ultimately the designers failed, but they were asked to do the impossible on that deal.

Paul
 
If you suspend a bridge, you build the bracing one way.

If support a bridge from below, you brace it a different way.

All the stresses are totally different depending upon where you 'hang' it from.

So, they designed it to hang from cables above, so that was the strong design of the bridge.

Someone with a big ego got it pushed through the idea of supporting it from below, first on big moving jacks (a whole 'bother set of stress to be moving to design for), and then from different points below from the ends and middle.

But a hanging bridge is very, very weak from below, those stresses had to be about impossible to calculate on the type of design this hanging bridge was. The ends and middle want to sag out and down from the load bearing points that are not properly beefed up, and from that backbone of supports that are angled the wrong way now when you try to carry it from -below-. Everything is opposite and backwards when you try to support it from below.

Bet there are some lowly engineers will be found eventually that were saying this won't work, it's not designed for those types of pressures, but were bypassed......

Paul
 
I would say that these engineering firms better start hiring from the YT site ...... a lot of experts here for sure.
 
Everything made today they make as cheap as they can and consequently pushing structural limits. When you start pushing limits it's only a matter of time before someone makes a mistake in fabrication pushing it over the limit.

I watched a strange show on TV the other day about what would happen if all people disappeared from the face of the earth. They said the buildings in our cities the ones built after WWII would fall before the older buildings just because the way they were designed.
 
IF a call comes in during bridge construction that cracks are developing in concrete that was not designed to crack, it does not take a rocket scientist to figure something is wrong and how could it not be safety related if the cracks were in structural support or tower support. It indicates a lack of proper bridge support from cables above or improper shoring below the bridge span. Someone made an incorrect call that this was not safety related. And what the hail are you testing suspension cable tension with the public on the street under the bridge???
 
The two summers I worked at the readymix company there was an Interstate highway going thru about 15-20 miles away. We made a couple pours a week there. An Inspector was on site at the computer controlled batch plant to record EVERYTHING. moisture of sand, crushed rock, water temp, weights of all materials, and made sure I zeroed out the rev counter on the drum, and the exact time I clicked the auto trans into gear to pull out of the plant. On the pour site were two inspectors. You poured a little concrete into an upside-down traffic cone which measured concrete Slump, they slammed it down right side up on a sheet of pkywood and pulled the cone off. Minute later measured height of concrete cone. Too short the concrete was too wet and your load rejected. Ohhh, they checked turns on the drum, had to be 55 to 70 or something like that, too few and you took the load back to town, too many, same result! Then you filled their steel form with concrete, form was about 5-6 inches square and 24 inches long. They scratched numbers into the wet concrete and set the full form off to the side. You now were able to unload. We unloaded into 1 cubic yard buckets, bottom dumping hoppers hooked to a 50 ton capacity American crane with a very expert operator! You didn't put ANY chutes on, didn't even flip the second chute down, the helper spotted the bucket an inch or two from your truck, you swung the chute over and rotated the drum till the bucket was plumb full and swung the chute back out of the way, the crane operator smoothly raised the bucket to the pour and 20-30 seconds later it was hovering inches above the ground moving slowly towards your truck and at the helpers signal dropped onto the ground within a quarter inch of the last position. Seven buckets and my truck was empty, they sign your delivery ticket and you pull away to the rinse area, clean your chute, and head for the plant for another load. Not unusual to have 3-4-5 trucks at the pour. One unloading, one pouring test bars & cones, one washing up, and one just getting on site. Very well run operation. 15 minutes was typical time on pour site, never over 20 minutes.

Wisconsin DOT put a steel walkway bridge across the Beltline highway on the south side of Madison, Wi. 3 years ago. Road is 2 lanes each way, narrow center median with center bridge support, and the approaches to the bridge are set back close to the edge of the right of way, plus the bridge sits at an angle, so longer than it would have had to be. It hasn't collapsed. Maybe Florida U should have the next bridge be made of steel? Or have a Tunnel built!
 
No kidding you would have thought that street would have been closed till all tests were done and double checked when you look at all the pieces that broke tells rite off something is realy just not quite rite with the plan
 
Hi Showcrop this same engineering firm is building a bridge here in NH. NH. Dot. says they are doing a good job and everything looks good and should be
done next wk. I sure hope so.
 
(quoted from post at 11:21:00 03/17/18) Hi Showcrop this same engineering firm is building a bridge here in NH. NH. Dot. says they are doing a good job and everything looks good and should be
done next wk. I sure hope so.

Which one? I93 Londonderry that I drive over all the time?
 
(quoted from post at 11:06:31 03/17/18) The two summers I worked at the readymix company there was an Interstate highway going thru about 15-20 miles away. We made a couple pours a week there. An Inspector was on site at the computer controlled batch plant to record EVERYTHING. moisture of sand, crushed rock, water temp, weights of all materials, and made sure I zeroed out the rev counter on the drum, and the exact time I clicked the auto trans into gear to pull out of the plant. On the pour site were two inspectors. You poured a little concrete into an upside-down traffic cone which measured concrete Slump, they slammed it down right side up on a sheet of pkywood and pulled the cone off. Minute later measured height of concrete cone. Too short the concrete was too wet and your load rejected. Ohhh, they checked turns on the drum, had to be 55 to 70 or something like that, too few and you took the load back to town, too many, same result! Then you filled their steel form with concrete, form was about 5-6 inches square and 24 inches long. They scratched numbers into the wet concrete and set the full form off to the side. You now were able to unload. We unloaded into 1 cubic yard buckets, bottom dumping hoppers hooked to a 50 ton capacity American crane with a very expert operator! You didn't put ANY chutes on, didn't even flip the second chute down, the helper spotted the bucket an inch or two from your truck, you swung the chute over and rotated the drum till the bucket was plumb full and swung the chute back out of the way, the crane operator smoothly raised the bucket to the pour and 20-30 seconds later it was hovering inches above the ground moving slowly towards your truck and at the helpers signal dropped onto the ground within a quarter inch of the last position. Seven buckets and my truck was empty, they sign your delivery ticket and you pull away to the rinse area, clean your chute, and head for the plant for another load. Not unusual to have 3-4-5 trucks at the pour. One unloading, one pouring test bars & cones, one washing up, and one just getting on site. Very well run operation. 15 minutes was typical time on pour site, never over 20 minutes.

Wisconsin DOT put a steel walkway bridge across the Beltline highway on the south side of Madison, Wi. 3 years ago. Road is 2 lanes each way, narrow center median with center bridge support, and the approaches to the bridge are set back close to the edge of the right of way, plus the bridge sits at an angle, so longer than it would have had to be. It hasn't collapsed. Maybe Florida U should have the next bridge be made of steel? Or have a Tunnel built!

Dr. Evil, During the work on the "Big Dig" job in Boston, they kept very close track of the redimix trucks to make sure that the load was fresh. If the time elapsed since the truck was loaded went over the allowed time, the truck was sent back to the plant to dispose of the load. At the plant, no problem, they added water, punched it a new ticket and sent it back to the job site. At least until a driver blew the whistle. My neighbor tells me that he was the whistle blower, but others have told me that it was someone else.
 
Like I said earlier, the concrete mix had Titanium Oxide in it for 'colorant'. That bridge was built and left to cure (hopefully)28 days BUT the test cylinders are subject to that same 28 day time period. If ANY tested weak, how to determine where on the bridge the defective product was placed? Slump is a good indicator but the additive for colorant? I was always taught that anything added beyond the four basic ingredients weakened the ultimate product.
 

The sad part is that 6+lives were lost because others had such a big ego they would not allow at least one lane out of eight to be occupied by cribbing until the remaining bridge support system was complete.
 
I remember that they said they would design the new bridge as they built it. That made no sense to me. Then why isn"t that always done?
 
I really gotta wonder about Florida...it started with hanging chads, then progresses to the school shooting and the lack of response, now the bridge falling....
 
Well its been established who doesn't have a clue about what they are doing and that's the folks down in Fl that were working on and inspecting the bridge.Hint you don't use a bridge with big fresh cracks in it.DUH!
 
concrete cylinders are taken to test for strength. Concrete strengths are based on a normal cure of 28 days, We built prestresed concrete beams and with steam curing would could get the 28 day strength in 12 hours many bridge components are constructed off site and assembled at the job site
 
we always had one of our own inspectors in the batching plant and he issued our own load ticket to the driver. if we rejected the load we took the ticket so the load could not be returned to us.
 
What about the engineer who designed the human body? In spite of all the joints it
was not a mechanical engineer. No, it was not an electrical engineer either, despite
all of the nerve endings relays etc. It was a civil engineer.....who else would
locate a toxic waste conduit right beside a recreational area.....
Ben
 

I think it was called "After People" Interesting concept. Watched a lot of it on YouTube.
 
(quoted from post at 21:15:47 03/17/18) I really gotta wonder about Florida...it started with hanging chads, then progresses to the school shooting and the lack of response, now the bridge falling....

The heat makes them crazy. I have family there, so I know.
 
Saw that show on the new Quest channel. New York city in 100, 200, so on to 1000 years from now. The only thing was, the indians didn't show up to reclaim!
 

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