Rubio: "The cables that suspend the bridge had loosened"

[dalton99a]

Link to tweet

http://www.miamiherald.com/news/local/community/miami-dade/west-miami-dade/article205316174.html

Late Thursday, came the first definitive word from a government official about what was being done on the bridge when it fell. U.S. Sen. Marco Rubio, R-FL, said in a Twitter post that: “The cables that suspend the #Miami bridge had loosened & the engineering firm ordered that they be tightened. They were being tightened when it collapsed today.”

Rubio, a Miami Republican, did not elaborate on the information. But he was in a position to know inside details about the catastrophe.

He traveled to the FIU campus Thursday on same plane with (FIU President Mark) Rosenberg. He said he spoke to MCM partner Pedro Munilla amid the rubble and he attended private briefings at FIU.

[Demovictory9]

1. So something had gone wrong within hours of installation

[TheBlackAdder]

10. A 175' suspension pedestrian bridge in an area prone to hurricanes. What the fuck were they thinking?

In NJ, we have pedestrian bridges spanning 8-10 lane highways with a median strip and no need for suspension wires.

They're built like brick shit houses and would survive hurricanes better than that piece of shit standing in dry weather.

[Blue_Adept]

15. It was designed to withstand a cat5 hurricane. So they knew what they were thinking.

[mchill]

26. I head that NWS is establishing a new Cat 6 :)

[Blue_Adept]

30. Definitely a necessity in the state of things.

The hurricanes last year showed how well Florida has handled things with changes made to structures and requirements over the years. They'll continue to improve as well, though it'll always be a "trying to catch up" thing.

[Tipperary]

47. I doubt that.

[Blue_Adept]

49. Wouldn't it be smart to search before saying that?

"Since the scale is now used as much in a scientific context as it is a damage assessment context, it makes sense to introduce a category six to describe the unprecedented strength 200 mph storms we've seen over the past few years both globally [Patricia] and here in the southern hemisphere [Winston]," said climatologist Michael Mann, director of Penn State University's Earth System Science Center."

"Scientifically, [six] would be a better description of the strength of 200 mph (320km/h) storms, and it would also better communicate the well-established finding now that climate change is making the strongest storms even stronger," he said.

Climate scientists mull Category 6 storm classification, report says
: https://www.cbsnews.com/news/climate-scientists-mull-category-six-storm-classification-report-says/

[Mariana]

52. Better to drop the stupid Categories altogether

when they're talking/writing/reporting about a storm, and tell us the sustained wind speed in the first place. "Category 3" conveys less information than "125mph".

[TheBlackAdder]

33. Rubio, an adjunct professor there, said it was a new and innovative design. ie. Never tested before.

[Retrograde]

34. Is he a professor of engineering?

Otherwise his opinion bears no more weight than yours or mine - and no where near that of a trained and licensed engineer.

[TheBlackAdder]

36. He's a prof of Graft and Kickbacks, which might make him qualified as a building code inspector.

[LisaL]

45. Yet somehow it didn't withstand even in the normal weather.

[Blue_Adept]

46. Oh, we know weather is what caused it?

[Generic Brad]

48. Yet it could not withstand a 5 mph wind

Definitely a serious design problem.

[Blue_Adept]

50. Ah, then we learned officially that it was a 5mph breeze that caused it?

Can you send me a link? I've not been awake too long and haven't seen that confirmation yet.

[Generic Brad]

53. Just being snarky

Clearly there was no Cat 5 hurricane in FL when it collapsed.

[NCTraveler]

22. Skyway bridge.

Suspension bridges are not weak and if constructed properly can withstand a cat5.

[Demsrule86]

17. Manaford was involved somehow tool.

[csziggy]

41. Last year Manafort was hepling a Chinese company take over the bridge builder

Company.

https://therealdeal.com/2017/08/31/meet-paul-manaforts-real-estate-fixer/

[Demsrule86]

44. Now, hubs company had parts made of Chinese steel...shitty steel...they had to scrap them and have

them remade.

[ProudLib72]

2. This is a funny response

Link to tweet

[Rhiannon12866]

6. Thanks! I wondered if there was any pushback...

[MontanaMama]

12. Does Marco have any reason to

defend the company who built the bridge? This sounds vaguely defensive.

[exboyfil]

3. If they were concerned about the bridge

Why didn't they do something unique like not let people go under it.

[LisaM]

5. Exactly.

I am concerned that it wasn't cordoned off.

[samir.g]

4. Post tension cables

[TheBlackAdder]

7. So they were securing the pedestrian bridge while allowing vehicles to ride underneath it?

[Rollo]

9. I suspect they had an institutional animus against shutting down traffic...

Because the whole idea of this type of construction was to avoid disruption of traffic below, or at least keep it to a minimum.

I guess they'll have to revisit that approach.

[Retrograde]

35. Back in the early 2000s

The port of Oakland, CA bought some large cranes from China. They had to be shipped in under the Golden Gate and Bay Bridges: they were large enough that they could only clear the bridges at very low tide. The Golden Gate Bridge is high enough that that wasn't a problem. The Bay Bridge - even at the lowest tide that month - only had about a foot of clearance, and that was during prime commute time. Shutting down traffic on the bridge would disrupt the main link between San Francisco and the East Bay: the bridge carries thousands of commuters back and forth each day. And it was highly unlikely that the boat with the cranes would hit the bridge anyway - they hoped. So what did the local authorities do? They shut down the bridge for half a day, inconveniencing quite a few people (and providing entertainment for countless others with "all cranes all the time" coverage), the boat and its cargo slid under the span with barely room to spare, and a few hours later everything was back to normal.

Maybe it's because the current favorite pastime on the SF Peninsula is playing "Guess Which Road is Closed Today" (Hint: it's the one I want to use), but temporary closures due to construction of various kinds is just part of normal day life. And when CalTrans needs to do major work on something like the Bay Bridge they pick a holiday weekend to do it and plaster the roads for fifty miles around a month ahead of time that they're going to be doing it. Surely closing an intersection - even on Calle Ocho - for a few days to do a major piece of engineering is an option.

[Rollo]

42. Must have been this one...

https://www.sfgate.com/bayarea/article/BAY-AREA-Huge-cranes-clear-Bay-Bridge-by-5-feet-2725244.php#photo-2177806

[Rollo]

43. or this...

[Rollo]

8. There's got to be more to it than that...

The cable tightening should have strengthened the structure, not weakened it further.

It's hard to know at this point, but I'm wondering if perhaps some vital bit of hardware was left out of the structure, which otherwise would have prevented the collapse.

Other possibilities include substandard materials, improper assembly, or just plain bad design.

[TheBlackAdder]

11. Other possibilities include substandard materials, improper assembly, or just plain bad design...

Missing hardware too.

I bet it's all of the above, plus a little graft to grease the process.

[RKP5637]

28. Wouldn't be surprised. I recall well the Boston tunnel wherein the huge ceiling tiles

started falling on cars.

The National Transportation Safety Board released a report on the one-year anniversary of the disaster, that attributed the major cause of the collapse to "epoxy creep".[11] On August 8, 2007, a Suffolk County Grand Jury indicted epoxy company Powers Fasteners, Inc., on one charge of involuntary manslaughter, with the maximum penalty in Massachusetts being a fine of one thousand dollars.[12]

The epoxy used in the D Street portal that failed cost $1,287.60. The cost to redesign, inspect, and repair all of the tunnels after the collapse was $54 million.[13]

https://en.wikipedia.org/wiki/Big_Dig_ceiling_collapse#Problems_identified

[muriel_volestrangler]

14. This is the best article I've found so far, with actual engineers commenting

As was the case with the FIU bridge, the structure typically is assembled from pieces placed alongside the road before being moved into place. Cables running through the bridge slab that are tightened to strengthen the pre-fabricated portions are adjusted and stress tests completed before the pieces are moved over roads, for obvious safety reasons.

If workers were adjusting cables once the bridge was in place, the cables should not have connected to the bridge’s structural integrity, Verrastro said. “Once you’re done tensioning those cables, you’re done,” he said.

It’s possible the cables were over-tightened, causing the bridge to elevate slightly in what’s called a camber. Adjusting the cables to address camber would be appropriate, but that would not impact the structural strength.

“If they were adjusting the structural cables, it was to try to put more or less camber,” he said.

http://www.miamiherald.com/news/local/community/miami-dade/article205422719.html

[FarCenter]

24. Good article. I would bet that the span was self-supporting with only a low margin of safety

It was probably designed with just enough strength to be hoisted into place as a single span truss.

Then the central tower could be completed and the stay cables attached in order to achieve the strength needed to support the live load of a crowd of students jumping up and down or a Cat 5 hurricane.

I'm mystified as to how they were going to erect the second span across the canal.

[muriel_volestrangler]

25. They could probably build a temporary bridge or pontoon across the canal

that they could wheel the jacks over that they'd then use to raise the section - it doesn't look like a canal that blocking access for several days would be a problem on.

There's a video from security cameras showing the moment of collapse - it looks as if about 5 workers were standing on the roof of the span, at roughly the point where it buckled, at about where the supporting cable closest to the tower would connect. It's a bit difficult to see, but to my eyes it looked like the roof buckled first.

Link to tweet

[FarCenter]

29. Or maybe the walkway breaks at the point where the first two angled members meet it

Those angled beams would transfer the load of the roof to the walkway at that point. I had thought that the center end might have slipped off the central pier, but that is clearly not the case. It buckled somewhere near the central pier.

[DrDan]

23. could they have over-tightened the cables - perhaps to the point of breaking?

We had a lot of post-tension work done on a condo we own in Florida - several of the cables were down to a few strands and needed to be replaced, so they are not indestructible

*********************
Probably not - just a random thought while reading through the thread

[Cattledog]

13. Why didn't they block traffic while it was being done?

MCM has a poor safety record.

[Girard442]

16. It's vitally important to know exactly what went wrong, but...

...don't let discussion of the technical minutiae obscure the fact that this was an instance of egregious human incompetence.

[FarCenter]

18. What cables? The central tower and the stay cables had not yet been erected.

Anything a politician says about the structural engineering of a bridge is probably fake news.

[DrDan]

20. I think they are referring to the post-tension cables - they run through the center of the concrete

[bullwinkle428]

21. EXACTLY MY RESPONSE WHEN I READ HIS TWEET. The entire superstructure

with the descending cables wasn't even in place!

[Javaman]

19. fuck this idiot, I'll wait for the investigation is completely before I listen to someone

who has zero engineering background.

[Alea]

27. My best guess

An eye witness said something, a cable, the cable hook, or where the cable was attached to the top of the bridge gave way, and that's when the bridge collapsed.



I.E, they were partially lifting the bridge from the top cable suspension points. When the cable let go, the bridge "dropped" and broke in what they call a drop collapse.

I suspect rubio heard cables blah blah and made a foolish judgement.

[Brother Buzz]

37. That big ass crane arrived post collapse

The little 'crane' that was in position prior to the collapse was used to lift the workers up to the span.

[Alea]

38. You should watch the video of the collapse

Link to tweet

The large crane was lifting on the bridge. You can even see the cable snap upward when the bridge came down. The witness said they moved it out of the way afterwards.

Screenshot of moment cable breaks loose

[Demovictory9]

39. The bridge looks like slabs of unreinforced concrete

[bdtrppr6]

31. i saw planned pictures compared to state of bridge just prior to collapse

there was middle support left out/off for some reason. I may be wrong but you can't build a span that wide without support from below or above. There were none that I could tell. Somebody didn't do their fucking job.

In case anyone is unaware, Rubio's a dumbass, don't listen to a word he says!

[TheBlackAdder]

32. Rubio, . . . intended to be an an innovative and one-of-a-kind engineering design.

.

Rubio, who is an adjunct professor at the school, noted the pedestrian bridge was intended to be an innovative and “one-of-a-kind engineering design.”

Renderings showed a tall, off-center tower with supporting cables attached to the walkway. When the bridge collapsed, the main tower had not yet been installed, and it was unclear what builders were using as temporary supports.

An accelerated construction method was supposed to reduce risks to workers and pedestrians and minimize traffic disruption, the university said. The school has long been interested in this kind of bridge design; in 2010, it opened an Accelerated Bridge Construction Center to “provide the transportation industry with the tools needed to effectively and economically utilize the principles of ABC to enhance mobility and safety, and produce safe, environmentally friendly, long-lasting bridges.”

https://www.snopes.com/ap/2018/03/16/fallen-bridge-stress-test-preceded-collapse-killed-6/


Yet, they still allowed vehicles to be underneath it when they were working on it.

.

[UTUSN]

40. And RUBIO has dibs on an expert opinion about anything from guns to bridges: be-CAUSE ?!1

[groundloop]

51. Everyone is missing this: "THE CABLES HAD LOOSENED"

IF (and that's a mighty big IF) Rubio has his facts straight, cables supporting the structure had lost tension. Nobody seems to have investigated WHY the cables lost tension, for that to happen something had to have moved or broken.

As an engineer I'd have wanted to know why those cables lost tension after having been installed, they couldn't have magically loosened themselves.