Only arrogant hubris, certain of their superiority and know-how, would have tried moving a bridge in place without first blocking road traffic. And the DOT explanation is that they weren't requested to do so????? Murder.
10
God bless Sergeant Mendez.
Let us never forget first responders, who run in while everyone else is rushing out...
6
As a former amateur guitarist (former due to arthritis), this tragedy reminds me of a too-tightly wound string suddenly breaking , becoming unwound, or becoming unanchored. A moment of chaos, followed by "I thought that was too tight." I hope that's not what happened here with a cable. All a guitar player gets is a literal slap on the wrist. Here, lives were at stake. Whoever was in charge of tightening cables could not afford to be an octave high.
2
Decades ago, I was in an entry-level Civil Engineering course in Structural Mechanics. On the first day the Prof said, "People have a right to expect that if a Professional Engineer (YOU) signs off a bridge, or any structure, you've done all your calculations correctly and it's safe to cross or enter." I went on to another major, but I admired that guy. He was a gate-keeper and no one was getting a "gentleman's C" from him. Are those guys gone?
12
What a terrible thing to happen and more people suffer. Do it fast, do it quick, do it cheaper than anybody and turn out shoddy work that takes lives. Is this the American way? And, of course, blame the other guy.
13
My take: In the end, the collapse will be determined to be the fault of MCM (Munilla Construction Management) - a politically connected company. This construction failure is not their first.
See --> https://heavy.com/news/2018/03/munilla-construction-management-mcm-built...
6
on the news the drawings of the bridge seemed to show a central supprt column and cables helping to supprt the span. these aren't there in the pictures I see of the collapse
2
The company that designed the bridge, Gibbs, has a very pretty web page talking about bridges as art.
OK, Gibbs, what do you call this piece of art of yours that killed six people? Neo modernist classical destructionist nihilistic abstraction?
I can't wait to see what the plaintiffs lawyers do to you Gibbs, and watch your licenses disappear along with your insurance company and your business. You deserve it. Really. You do.
While we're on the subject, I'm marking down each and every bridge you've done, and I'm staying off of them all much less ever going underneath one.
6
Are we great again?
10
A recent study in Louisiana found 2,000 structurally deficient bridges in the state out of the nearly 13,000 bridges. I shudder when I think of this and all of the people that are crossing and passing under these hazards daily.
2
Richest 3rd world country on the planet -- USA! USA!
9
Sergeant Mendez should receive the highest commendation from the City of Miami for her heroic efforts. She could have simply "called it in" to emergency dispatch, but she climbed the rubble to offer assistance and then..and THEN, she crawled beneath collapsed, unstable tons of concrete.
10
Andy, you hit the nail on the head, "unless a safety culture is prioritized, financial considerations will exclusively rule the day." That is the state of our work culture today hence the resulting outcome....
6
I'm not an engineer.
I can't understand why there were no temporary mid-section supports in place until bridge was totally supported and secure. If final plans show a mast in the center with cables supporting the bridge, that would indicate to me the need to support the bridge during construction.
And those cracks... why no backup contacts at Florida transportation department? The cracks alone should have given that engineer the authority to shut down the roadway and reroute traffic. Leaving a voicemail simply does not cut it.
19
We were warned to worry about the danger from our aging infrastructure. Now we must fear our new infrastructure as well.
Remembering that rocket science and rocket scientists were behind both the Space Shuttle Challenger and Columbia disasters should be very humbling in reviewing this pedestrian bridge accident. Hubris is human.
12
It's been said before: One of the characteristics of 3rd world countries is that new construction collapses. Could be from corruption in building contracts, unwillingness to pay for experienced workers. lack of know-how of construction company administrators, laziness, lack of effective oversight by inspectors, cutting contract costs by cutting "extra strength" measures from the design.
8
This looks to be a classic case of over design and over engineering. Was it really necessary to have all those benches and accouchments on a pedestrian bridge that was only about 100-150 feet long? Why was a roof that added so much additional weight to the project necessary on a short pedestrian bridge? Why was it built using accelerated construction? A textbook case of hubris engineering at its worst.
9
Hold the presses, everybody! Now the NTSB insists that this is not a stayed-cable bridge; that the tower and fan of cables was mostly a cosmetic and vibration-dampening detail. That is, not holding it up. Although, of course, had they been in place....So the deck that fell was supposedly a self-supporting truss. Worse, the operations on the ‘loose’ cables in the diagonal truss members that were going on as the collapse happened, and the reported cracking, could be the proximate cause. Now, engineers, if this thing was really a truss, what would you think about truss post tensioning cables becoming loose? For everyone else, we can stop being horrified that only half the structure was in place, no cables, no tower between spans - and, to quash all common sense opinions, the assembly procedure of putting the span out by itself would have been technically correct. Back to square one: wrong engineering, faulty construction, and for the fatalities, criminal disregard for public safety after disclosure of problems.
6
We will see more and more of this as schools replace science and math with social justice courses.
Three words: abundance of caution. Why the street traffic wasn't halted during the tightening process ... from a layman's perspective, that's inexcusable.
7
Reading the comments regarding this tragedy over the last several days I continue to be astounded by the number of, apparently, licensed Professional Engineers with advanced knowledge of structural/bridge design who have already ascertained the cause of this collapse and also who to blame. Their forensic investigative abilities seem supernatural, lets get them on the official team and wrap this up in a week or so. No need to visit the site.
3
Speed kills, which in this sad case is entirely true.
These days, especially in construction, the goal is to build it fast, using questionable engineering design, using the least expensive materials, the cheapest inexperienced labor, circumventing as many construction codes as can be gotten away with, and on, and on its goes.
This tragedy will be old news in a week for most, but for the survivors and families left behind, it will forever be a sad unforgettable part of their lives, affecting them in ways we can't imagine.
Next will come insurance payouts, and fighting over responsibility among contractors and subcontractors, and the various insurance companies, with payouts deliberately reduced, and deliberately delayed for years.
Yes indeed, our American lack of empathy on worldwide display; talk it up a storm, offer empty platitudes, and move quickly on ...
2
Weren’t the absent cable stays critical supports? How would the bridge stand without them?
This is the kind of mistakes and shoddy workmanship and lack of knowledge that happens in developing countries, not in the US. This is what we’ve become. And lives are lost as we realize this. So sad.
2
FIU is known for educating students from Third World Countries using the American spirit and know-how. Soon it will be the other way around.
2
Gee I guess that design didn't work after all. Back to the drawing board. We'll test the next version on the public next week.
1
I am surprised at the wealth of knowledge demonstrated by the readers of the NYT.
So much engineering knowledge is to be commended.
The in-depth research of the design, construction and deployment of this specific bridge is also to be heartily commended.
To gather so many experts on one site is also amazing.
14
If they were working at and on the bridge as I've heard and read in several news reports, why wasn't the traffic stopped on that street going under the bridge?
4
I’m sorry, but for something as potentially catastrophic as cracks in a bridge under construction, you don’t leave a voice mail that won’t be returned for a couple of days. You keep trying until you talk to an actual human being.
But second-guessing really serves no point now, so the question becomes — as it always does — will anyone learn from this in the myriad investigations that are sure to follow, or will speed and cost-cutting still reign supreme?
4
Seeing the Chevy which was one of the two vehicles recovered from under the collapsed makes you cringe in horror. It is flattened almost into a sheet of metal. And the driver? One cannot even imagine what was left embedded and becoming one with the metal. Horrifying - I cannot find any other words to describe.
4
Apparently, this ABC method of bridge building has been in use for some time now. Are all the bridges across the U.S. which utilized this construction method going to be examined for faults? Makes one wonder (not in a good way) when driving over or under a bridge.
1
We, all citizens eager for infrastructure to be tackled by this Admin and this congress - need to use this tragedy as a tempering agent. Yes,we need the work to be done, but we need it done properly! To last for generations, like the stuff in need of repair, or replacement. We don't need the typically closed bidding processes, where the well-connected, and outright corrupt get the bigger pieces of the money pies. What we need and demand is transparency and assurances that the best are hired.
Any and all such projects be they new, ongoing and/or on the drawing boards - need to be checked and then checked again. Any projects involving public funds, and partake of the public bidding process need to be carefully reviewed. The public bidding processes all across the nation are woefully flawed and rife with corruption. Corruption that is either outright, and overlooked (intentionally, or due to lack of adequate oversight) or that is built-in to the system...where contracts are only handed out to well connected businesses. Too often connected to our locally elected public employees.
Whatever the final verdict, its a fair guess that someone/s short sheeted some beds somewhere. Materials were substandard, the concrete mixing and curing processes were thwarted/undermined, inspections were performed lazily or not at all, or the simplest of procedures (like properly torquing some bolts/nuts) was overlooked due to poor management, and the hurried desires of the involved parties.
4
Deregulation’s, lax laws, isn’t this the result of Trump’s new form of government? Poorly built? Who is responsible here? The mayor? The Florida Governor? Or the corruption in general? I really hope the families of the victims sue all the responsible.
4
I cannot understand why traffic was not diverted until the bridge was completed and tested.
6
This kind of accident happens in developing countries. It should not happen in the US. It is more evidence that the US is falling way behind western Europe on all levels of development. Appalling.
4
The virtual total reliance on electronic communication, as opposed to face-to-face communication, was clearly a major contributor, perhaps the sole contributor, to the cause of the bridge collapse. When is this nonsense going to stop?
7
1) you are in charge of putting a 950 ton bridge in place and you don't check your voicemail/email--just to keep up to date? incompetent
2) cracks are seen but a priori assumed safe? Cracks in a house foundation are enough to kill a sale
3) there's a time lapse video available online showing the full placement - two cranes one holding up the center, the second holding up one end- a third of the bridge hanging free without any undersupport. The stress on that free side must have been incredible. So, is that the side that also had the crack?
4) if there's any justice, many companies and personnel will being going down for this.
6
“We’ve taken a look at it and, uh, obviously some repairs or whatever will have to be done, but from a safety perspective we don’t see that there’s any issue there so we’re not concerned about it from that perspective,” said the engineer, W. Denney Pate. “Although obviously the cracking is not good and something’s going to have to be, you know, done to repair that.”
That’s all folks.
5
Lead Engineer should have known while the design was still on paper the bridge won't stand. That's why you go to Engineering school for. Not to mentioned that this is a simple structure.
I see incompetence everywhere from the train the won't run to the government employee who has no clue and passing by these horrendous cyber-security breaches. Are people held accountable anymore? Incompetence and unaccountability eats into this country's vitality and potential.
3
It is a bit surprising that nothing has been set up to lift the collapsed bridge. I'm thinking about fast setting equipment like hydraulic jacks, wheeled crane. Perhaps those two cars with the front under. I believe that two jacks each side of the cars and a winch pulling it would have been sufficient to free it and maybe save the occupants if they are still alive. Perhaps the rescuers could not do that in the circonstances.
2
With Trump’s deregulation and, as Steve Bannon put it, “deconstruction of the administrative state,” expect a lot more of such avoidable tragedies.
2
This was not so much an engineering problem as a problem of lack of government regulation.
In an effort to squeeze profits by rolling back safety protections, lives are lost. How is this different from the Deep Water Horizon disaster? The Trump administration recently eased Obama-era safety and environmental regulations that were adopted after the Deepwater Horizon disaster killed 11 people.
As the New York Times headline declared:
Trump Rollbacks Target
Offshore Rules ‘Written
With Human Blood’
https://www.nytimes.com/2018/03/10/business/offshore-drilling-trump-admi...
This is no way to move forward being pennywise and pound-foolish. Cutting corners does not lead to a flourishing economy, it leads to bankruptcy (something Trump is very experience in accomplishing).
7
I admit I know nothing about engineering. Nonetheless, when I heard “accelerated bridge construction” alarm bells went off in my head.
What a horrible thing to have experienced-kudos to the Times reporters for humanistic coverage.
Yes, as everyone points out, the bridge was poorly designed. But a simpler issue here is that the motorists were forced to stop for a traffic light and sit under the bridge. I can think of many examples of this in my own city and every time I'm pinned in traffic under a bridge I look up at the often rusty, crumbling structure and pray for the light to turn green. Why not move the light when possible so the cars wait before the bridge?
18
In earthquake country I always think this under a bridge of any kind. The Loma Prieta quake comes to mind when the Nimitz Freeway pancaked and 50 or so people died in the rubble very much like this Florida scenario.
4
The reinforced concrete design for such a light but wide spanning bridge is to be faulted. The wrecking was foreseeable, sorry to say that.
4
Something seems terribly amiss in what is appearing more and more to be a completely preventable tragedy of incalculable human engineering and public safety errors. I don't even discount actionable homicidal neglect as a potential future charge. Cracks detected in post-erection material. Lack of secondary support beams during and following initial early installation followed by a seeming professional physical abandoment of the erected bridge itself without adequate public traffic safety initiatives followed. (stopping traffic flow under the bridge until supports are installed and materials assessment, post-erection completed).
This is not how most public engineering projects, historically, are supposed to be handled. Safety measures were looking more and more as if they were completely, and tragically- disregarded. This is looking more and more to me like a rush job- a rush- by management, to cut corners. Cost corners. Safety corners. What I'd like to know is- who, in management was refusing to look at it's own engineer's problematic data and take heed. My sense is that management became overly comfortable and lax in it's corporate ego to admit that their $$ project was compromised. Big people admit their errors fix the problem. I don't think this firm had the professionalism to do that. For whatever reasons.
15
Structural concerns about cracks in the concrete were sent by e-mail? Just left there? What about tracking down responsible parties, discussing, advocating for immediate action before proceeding further? I don’t understand the lack of tenacity and professionalism in pursuing action when faults were noted before further load testing or construction took place.
35
Everything has to be done fast nowadays. Fast food, fast text messages and now six-hour bridge construction.
Slow and steady is what wins the race.
In any event, regardless of how long it took to build this thing, foot and pedestrian traffic should have been diverted from this bridge while it was still under construction.
27
Perhaps this will turn out to be one of those tragic incidents that could have been avoided had there been some specific regulation regarding that type of construction. “But regulations hamper profit making”, say the anti-safety folks, “and profits are more important than lives ANY day!”
61
What idiot would allow the adjustment without blocking the traffic? Beyond stupid.
43
As retired bridge engineer it's obvious that the bridge needed temporary piers mid-span to accommodate loads until cable stays were placed. Design engineers who approved erection drawings screwed-up.
50
How many engineers does it take to build a suspension bridge without the suspension system? I wouldn't trust these engineers to screw in a light-bulb.
Who decided it was OK to allow traffic or anyone underneath an unsupported span designed to be held up with cable stays from above that were not there ... yet? A simple temporary support near the middle would have prevented the collapse, but could be knocked away by a typical careless driver.
They should have left one of the moveable supports, they used to move the span, to provide support under the mid-section until they finished the tower and stay connections.
37
The ugly dreams that trump's deregulations are soon to be made of.
63
It MUST be Trump's fault! Of course!
1
How can they not have lifted the pieces to find the bodies yet??! What if by some miracle someone under there survived? Where are the cranes?
23
The cranes are there. The structure was moved into place with hydrolic lifts; I think it is too heavy for cranes to lift as is. But they are trying.
2
Because it can not be "Just Lifted"!
There is 1,900,000 lbs of concrete on the road.
It has to be broken up and taken out in small pieces
As the machinery is working on it, the debris has been shifting. That means doing it slowly so workers are not injured
And No - NO ONE IS ALIVE (only someone ignoring reality thinks that). Geez... look at the photos on other website Cars stuck under there are pancaked - no one could survive that
FUrther the rescue team was able snake in cables with cameras and sound pickup to see where victims are and if any were alive
They are D E A D
2
There's really nothing to get a hold of, Boggle. It was made of reinforced concrete which has basically crumbled after the collapse. It needs to be removed chunk by chunk, unfortunately.
It might be sensible to check what had been predicted to happen in the US in the book: MARCH OF THE EVIL EMPIRES; ENGLISH versus the Feudal languages (archive dot org).
Simply acting blind to what is literally there written on the wall, will lead the nations to unforeseeable perils.
Totally disarray is in the offing. Just mark my words.
4
Who did the math?
The statics of the bridge were obviously miscalculated?
8
Only in Florida, USA. Even the new infrastructure crumbles.
19
Florida actually has a lot to offer. But this awful news and the awful news of the shooting in Parkland raise issues.
The designers and construction managers of the bridge must answer for this awful day.
And the school, school board, sheriff, psychologist(s), and FBI must answer for the deaths of 17 people who were shot and killed on that awful day. The school knew Cruz was dangerous. The school board knew he was dangerous. The sheriff knew he was dangerous. The FBI appears to not have done sufficient follow-up. Last but definitely not least, psychologist(s) spoke with him and the family he lived with and apparently cleared him as 'no danger to himself or others'.
2
Were there contractors responsible for building/installing the bridge, or did it simply appear by magic?
4
Yep. Including some affiliated with Paul Manafort's company.
Very funny that.
1
??? What material(s) was the bridge made of? Was there a single continuous steel beam or several supporting a concrete road bed?? What is the sag factor in all of this? If there wasn'Florida Transportation not moniot a continuous beam please explain this construction which is pot-lintel which means gravity pulls down on it. If the cabels were nedessary for support and against wind, why were they NOT in place? Why was there no temporary central support? Heads should roll.. Why the phone at Floridal DOT not monitored?
Wasthe cement substandard?? ditto the steel? Is this the right material to use forIs this sort of structure?? Would an arch even a slight arch been a better design choice?
Only questions at this point.. but one person did point out a problem and his voice went unheard... because a phone wasn't answered.. You should know the poem -- for the lack of a battale a country was lost -- etc. all for the lck of a horseshoe nail.
7
I'm not a fully qualified engineer, but I got near at one point in my past. Therefor I can ask these questions:
1) The design of the bridge looks solid, but there also was a pylon planned in the middle, to be added later. How can you do a load test until the last structural element is in place?
2) Why do a load test when cars/people are under the bridge? Why have workers on the bridge while doing a load test?
3) There was a report by Marco Rubio that the cables had gotten lose and were in the process of re-tightening. How die they get lose? What effect did that have on the concrete? How can you simply re-tighten the cables and expect everything to be okay?
4) The idea of rapid bridge building sounds great. But something obviously went terribly wrong. Were all procedures follow, as determined in the design and engineering process? Or was there some "grand opening" ahead of actually finishing, structurally, the bridge?
The last point is especially important since the University that ordered the bridge was the place where this rapid construction idea came from. IF, and only if, there was some delay while building the bridge on the roadside, and IF they decided to go ahead with the grand opening, bar the pylon, on a specific date that would be gross negligence among all the parties concerned.
I will watch this developing story with bated breath, but I got this sad, sick feeling in my stomach that once again it's going to be about money, prestige or stupidity in the end...
26
Best comment of the day!
1
The bridge looks really under supported and was apparently going to have cables to support it. So why didn't they have the tower and cables ready to go? What was the rush of installing the bridge without the supports when it wasn't even planned to open until next year? Somebody messed up big time on this one.
14
I do not yet know what happened there, but it is terrible. Of course, my most sincere prayers to the families of all affected.
I was in the 1989 Loma Prieta earthquake in CA, and none of us stopped under overpasses in traffic for months.
13
I still live in the East Bay. If traffic is stalled, I don't enter the underpass space. Won't take the BART tube under the Bay either - and didn't drive the old Bay Bridge for the last year it was in use. Not sure I trust the new Bridge either - not after reading about this tragic accident - but it is beautiful and California taxpayers will be paying up for exorbitant repair and upkeep costs for many years to come because of the faulty construction.
In all of our worries of sudden and inexplicable tragedy that might strike a loved one, this is of the most nightmarish.
Our hearts and minds cannot conceive of a disaster so cruelly and horrifyingly caused by human error.
Truly, our sympathies and condolences go out to the families of the lost and injured.
8
The Romans had it right!
Make the builder live underneath the project until completion.
26
My dad was in the Army Corps of Engineers. He always told me that after a bridge was built, the engineer in charge had to drive over it first.
But that would mean, he'd be living under a bridge. Not as bad as living in a van, down by the river, but, pretty bad.
Sometimes we try new ways of doing things and they simply do not work out. But if we quit experimenting, where would we be in twenty years?
Let's try to fix this system and have the industry decide whether this method is just right or too dangerous to try any more. This particular bridge seems to have started with a ''Tiger'' grant from the Obama administration, but no one can blame this on any president.
1
President Obama didn't build the bridge, nor did he decide not to divert traffic while it was being tested.
Neither did Trump. Let's leave the Presidents out of it.
17
Obama did not design the bridge. Money is needed for infrastructure, but intelligent use of that money is equally important, as is common sense at all stages of the process.
If “no one can blame this on any president,” then why bring it up?
1
I don't think we are in any danger of abandoning innovations and perhaps this was an unavoidable or unpredictable accident. But clearly the causes need to be identified so that this kind of disaster does not happen again. Discovering the origins of this tragedy will also improve our understanding of the materials and methods used to construct this bridge.
School projects belong in a lab.
Why did the city permit a bridge over a busy street without its main support -- tower and cable stays ?
The general public are not lab rats.
21
It's incomprehensible that they still haven't been able to clear the debris and recover the bodies. A competent construction company would have brought some heavy equipment and dealt with this emergency by now. Bizarre!
14
NOT bizarre! This is a potential crime scene. Evidence must be gathered so guilty parties can be dealt with for criminal and/or civil prosecution.
Both EMS personnel and law enforcement personnel would have done anything possible to remove survivors. But fact-finding takes precedence over removal of bodies.
2
It is sad that many were killed. My thoughts are with them.
The bridge was in essence still under construction without the towers and strings. Without strings’ pulling power as in the design, concrete mass would usually fall, I would imagine. Am I wrong?
Who allowed that concrete mass to support itself for a very long period of time? Then let’s ask who allowed the road to remain open.
10
Not to underestimate the capabilities of human stupidity, but to me the possibility that nobody thought to design this part to support itself, if that’s how they intended this to be constructed and there wasn’t a miscommunication as to when the tower was supposed to go up, is smaller than other possibilities such as miscommunication, some subtlety in design, or something with the construction. Everybody saying that obviously it needed the cables and tower may well end up being right, but I think it’s premature to say that for sure. Because it’s so blinding obvious that if you’re gonna put it up by itself it has to support its self weight, forces during construction, etc., that I can hardly believe nobody thought of that. But again, human error...
Also, it’s not just concrete, there’s steel on the bottom to handle the tensile stress. In a simple concrete beam the concrete carries the compression on top and the steel the tension on bottom caused by it trying to sag. In a pamphlet they described it as an I-beam section (putting most material on top and bottom because that’s where the bending causes the largest pressures in the material) which indicates to me they meant it to be able to resist some load at least. Maybe. I’m an engineering student so I don’t know anything beyond the very basics of concrete design.
The only thing I really know , is that building a bridge , something you can pick up a history book and see still standing in some form from the 4th century , building a bridge isn't a notion , not some kind of guess or "concept".....it is a science......somebody disobeyed ....the science. And they should suffer wrath.
19
Yes -- There is such a thing as science in this country. At least for now.
7
I'm going to be particularly harsh toward the licensed engineers who failed their customer, the public, their professions, and themselves, because engineers today deserve this harshness. Accountants and bankers drove this disaster and the engineers did nothing to stop them, they aided them and betrayed themselves completely. Why? Over the past twenty five years, engineers' professions have been target challenged by H1B visa immigrants, and the engineering professions responses have been to become more insular, clannish, and irresponsible to their core values, more willing to agree with the Accountant and Banking class. There is no acceptable engineering reason for erecting a brittle long span suspension structure without its central tower and support stays. It is in fact, insanity, lunacy. This was a suspension design, and I'm shocked and disgusted the construction went forward without the central suspension tower or stay supports, those are the first components erected. The MBA Engineer Architects can argue all they want to about the beauty of their designs and defend their decision to build a Brooklyn-Verrazano-George Washington style bridge without the center suspension tower, argue all the way into the courtroom, and they will. Accountants and bankers drove this disaster and the engineers did what? Nothing, except to ignore their educations and core values to put public lives in grave danger for a progress payment, for money. Go find another line of work. Disgusting.
40
According to the schematic accompanying the article, this was to have been a cable-stayed bridge, much larger versions of which have become a successful, standard design all over the world, including the Zakim-Bunker Hill Bridge across Boston Harbor and the new Mario Cuomo Bridge spanning the Hudson River.
But here they put the main span in place and removed the temporary supports BEFORE building the central tower and cables, cables that were essential to supporting that span. WHAT were they thinking? What kind of magic were they relying on to hold up the span till they finally got around to adding the tower and cables?
“Accelerated design?” BACKWARD design. Crazy design. Insane, unforgivable negligence. Epic lawsuits to follow that will not only devastate the university financially, but deservedly destroy the reputation of the engineering department that was, until an instant before this utterly unnecessary and completely avoidable collapse, promoting the bridge as a shining example of the school’s academic prowess.
Prison terms for whoever is responsible will be a greater kindness than they deserve.
34
It will be a tragedy of a different sort if the University goes under. As to the engineering department and student role, these are the folks who train our working engineers and who are hired by engineering firms so I suspect they are as qualified to design a bridge as any save those who have actually designed and built many bridges and have years of practical experience.
Sometimes, you expect this level of incompetence in a Third World Country, but here in the US? All you need is 2 very long Steel I-Beams connecting both sides of the road with a support in the middle. How could this engineering company be so bad? Was this something cosmetic, to be just looked at?
6
Why is it taking so little long to recover the bodies? Also, is it not possible that child could be alive perhaps on the floor of a vehicle?
9
Bonny, as a parent and grandparent, I understand your questions.
Almost certainly sophisticated listening equipment would have heard a living person beneath the collapsed concrete. The bridge's weight was given as 960 tons - 960 X 2000 = 1,920,000 pounds.
As to recovery of the bodies, again I understand your question. But this bridge is now a crime scene. Facts must be gathered for possible criminal and definite civil prosecutions.
3
Interesting how so many people here automatically assume more money would have made that bridge safe. Typical mentality. Completely overlooks incompetence.
(Has Trump been blamed yet?)
4
If he hasn't been, then this would be one of a very few bad things he isn't responsible for.
No but he's probably blaming Obama.
I wouldn't want to be the structural engineer who approved the plans for this bridge, nor the person responsible for testing the tensile strength of the concrete before it was poured and after it cured. Not only do we now have to fear infrastructure that has been neglected and is rusting and wearing out over decades, we now have to fear people whose education and morals may be less than advertised in the era of Trump and DeVos.
All sympathy to the victims and their families. This never should have occurred.
8
You write of fearing "people whose education and morals may be less than advertised in the era of Trump and DeVos".
How does your feeling correlate with the fact that the people who designed and built this bridge were educated years ago?
1
I I am confused by many of the comments which allude to some missing central pylon with support cables that had not been installed. Yet the video shows the entire span being installed as one piece. Where would this central pylon and support cables go then, off to the side. This doesn’t make sense. Could the NYT published a schematic of what the final structure was supposed to look like?
7
Maybe this question was previously asked but why was the support that moved the bridge into place moved prior to the bridge being secured? The road should have remain closed until engineers were confident the bridge was safe.
This is all so horrible!
3
I am an engineer with lots of experience managing construction projects. Here are my observations, the drawings clearly show that this bridge had cables overhead, ( we all are familiar the San Fransisco Bridge and other Bridges) . Their should have been shoring remaining underneath until all the over head cables were in a tightened. One can also see that the ends aren’t done all of that needs to be done.
Clearly, this is a minority contractor that has bullied its way with political donations to the Cuban political crowd of South Florida. 8a specialists and what ever local program they have in the local governments. The emphasis on “Family”business for an Engineering oriented construction business such as a bridge builder makes me really worried, especially in a Cat5. Too much family and not enough top tier Engineering degrees would make me very worried. This is not Jose’s Masonry or Jamie’s Concrete finishing type work.
11
Now it seems an engineer for Figg reported cracks at the north end by voicemail to the DOT. No action was taken with respect to this message, unless it touched off checking the PT situation. Again, covering the structural elements with a bunch of FIU banners might have hidden some developing cracks.
To those who think it’s unseemly to second guess things so soon after a tragic loss of life, I would agree, except for the likelihood that, without a visible, public discussion, educated or not, the incident will silently be forgotten, a few minor fines will issue, and it will be gone. Except, of course, for the grieving families and traumatized witnesses.
2
As a structural engineer, I'd like to thank you. I don't object to the dozens of comments second guessing the cause of this tragedy. Sometimes, an insight comes from an unlikely place, an observer who wonders something out loud. And, I like your comment about banners or flags covering up potential defects. That's something to consider for all construction projects.
But, I object to the vitriol and the know-it-all-ism by people who clearly are not engineers. It's outrageous, and it adds nothing. People are just venting their spleens to no purpose, while others are dead or grieving.
Your comment is made without judgment, spite, and nastiness. Thank you.
Finally, incidents like these are never silently forgotten. Investigations go on for years and years outside the public's eye. I remember an article about the chief engineer of the original World Trade Center towers appearing in this paper long after 9/11. The question of whether their collapse was due to a flaw in the original building design, or simply the inevitable result of fully-fueled large jets deliberately targeting the towers, had been examined exhaustively for years. Another factor that keeps investigations alive is litigation, which will most certainly shortly ensue.
You may think social media and comments sections keep an issue like this one from being forgotten or buried with a few fines, but you are wrong.
3
This is why we need good regulatory agencies...
5
What a horror. Heartbreaking. The builders also had a relationship with Paul Manafort.
1
Our hearts and thoughts go to the friends and families of the victims. Living in a developing country, reading about how this terrible, terrible accident could have been prevented, we feel that beyond all technology and sophistication, the people behind them and those who have responsibility to govern are the same all over. Hopefully preventive measures will be taken to minimize recurrence of such tragedies.
2
If anything good can result from this catastrphic failure, let it include a realization on the driving public's part that many of our bridges are obsolete, severely compromised and in imminent danger of failing while we or someone we are close to is upon them.
6
14 million for a bridge? In NYC they just repaired and painted stairs at a Elevated subway stop for 27 million....yup...27 million.
3
Be happy, Moe...........the same work might have cost 54 million in California.
1
Criminal negligence? Corruption? Incompetence? A horrible incident with lost lives. Someone will hang for this.
Remember that Florida's Attorney General Pam Bondi's price to avoid charges is only $25,000. I bet she will need more for this one.
1
I am so glad we gave tax cuts to "job creating" hedge fund kings. I mean why waste that money on thing like, y'know, fixing our roads and bridges that working stiffs use. The Hedge fund kings have their own helicopters.
7
Why was traffic not diverted to 30 yards just south of 8th street for the next 9 months until all work completed on the new bridge? This was literally an active construction site over 50,000 cars per day. Am I missing something here?
8
"The new efficiency" is actually ancient foolishness. "A stitch in time saves nine."
It is more efficient to construct with care and thoughtfulness with the time it takes to do things right the first time than to have to clean up the mess that pressured speed produces.
5
And we learn that cracks were noticed several days ago - by an engineer. No problem! Who are these people? Those lives are lost forever.
2
In China if a bridge that collapses, the designers go to jail. In America, they just get one more government contract.
4
False work missing to support bridge weight until cables stayes installed?
1
Faster. Cheaper. Safer.
Doesn’t it stand to reason that if something like a bridge is made quickly and cheaply, safety may be compromised? This may be the newest thing in engineering, and I understand the desire to keep traffic interruption to a minimum, but there are some things for which corners cannot be cut.
6
I am impressed (negatively) by the certainty of conclusions drawn by the Most Recommended comments before the facts are known. Though some comments may likely turn out to be correct, that is not the point. Real news, as opposed to "fake news" is predicated on making observations and drawing conclusions from the evidence, not cherry-picking the very limited "evidence" to fit predetermined assumptions and biases.
22
Thank you.
4
A pedestrian bridge, of simple time worn construction would still be standing.
High tech, quick miracle bridges are not the answer.
China has many, many safe , simple
pedestrian bridges.
There's a lesson to be learned here.
An unnecessary tragedy.
13
It just seems to me (and I am not a bridge engineer) that $14 million is not a lot of money to build a bridge of this magnitude; I’m wondering if contractors, construction crew had to build this bridge as fast as possible before the money ran out.
My deep condolences to the families that lost loved ones and hoping for speedy recoveries to those injured.
9
Looking at the drawings of the bridge as it would be when completed, one thing stands out: The two sections were not designed to be independently self- supporting. They depend on vertical support from the cable stays radiating from the central pylon.
The pylon should have been the first part of the project to be installed.
53
This is a pedestrian bridge. The maximum weight of the people that would walk across it would only be tiny fraction of the weight of the structure itself. That means it collapsed under its own weight.
We know that this is a cable stayed design. That means the cables support the weight of the bridge. But there were no cables because the bridge is only partially completed. If the bridge could support its own weight without the cables, then why were the cables necessary? Obviously the span could not support itself, and it collapsed because there were no cables to support it.
The cables would not be there for a safety factor. Bridges are not designed that way. The cables are an integral and necessary part of the design.
This is starting to look like a construction staging issue. Since the span could not support itself, some kind of mid span support(s) would have been necessary while the cables were installed.
Normally, the contractor would follow the directions of the design engineer during assembly.
The contractor has the right to stage the job anyway he wants, but the engineer has to approve the work as proposed. The contractor is only responsible for building the structure as designed.
So either the contractor staged the build without engineer approval, or there was no engineer approval, or an incompetent engineer approved the staging. If this was a design build project, then the contractor is the engineer and all liability rests with him.
117
Precisely.
3
I am impressed (negatively) by the certainty of conclusions drawn by the Most Recommended comments before the facts are known. Though some comments may likely turn out to be correct, that is not the point. Real news, as opposed to "fake news" is predicated on making observations and drawing conclusions from the evidence, not cherry-picking the very limited "evidence" to fit predetermined assumptions and biases.
70
So don't read the comments. Many of us, myself included, are capable of forming our own opinions based on reading articles related to cable bridges, etc. Comments are unrelated to journalism and we know that. Some here are engineers and attorneys familiar with design and installation.
7
No one is claiming that their comment is real news or fake news. Comments are not news -- we NYT readers know that.
8
These comments are not news, of any kind. They are speculation. If you want to read a report of verifiable facts, the comment area isn’t the place to go. However, people have a right to use the information they have to speculate.
I'm sure it will come to light that the builder was cutting corners to pocket the money saved by cutting corners. However, I feel that the University, and the city, are at fault for not closing the road for safety reasons, there were no workers on the walkway for that reason. I'm sure no one expected it to collapse, I'm sure the designer can properly design a structure that can carry it's own weight until other components are installed, as in this case the cables that would ultimately carry the full weight of the walkway, both with and without pedestrians.
This is the problem with the bidding system assuming the university did use the RFP, or bidding process, is that often times the winner is the low bidder, that can't possibly do the job without cutting corners. Although, the the contractor won't say that, they just want to get it built to receive the money for finishing a project in time and under budget. What happens if the contractor goes over budget during the building process, what is the University going to do, stop the building of the walkway, and get the second place bidder on site and building, the short answer is no, they aren't.
It's sad that people lost their lives for something so avoidable, like closing the road, until the test was done. Or making sure some sort of safety procedure was in place during the construction of this walkway. If it were my loved one that was killed, I'd be looking for an attorney and holding everyone to account.
32
Everyone is so correct that says that the roadway beneath should not have been opened yet. It wasn't finished or tested. That is very clear. And a terrible major tragedy happened.
Still even if closed it would have come down. The support structures that should have preceded the structure's placement were not installed. Step 1 was never done before step 2. Nor did step 3 and 4 happen before the roadway was opened. The cost of some agencies incompetence was dear.
29
Was a pedestrian tunnel out of the question? Here in coastal Los Angeles, they recently shut down short sections of Wilshire Blvd. just on the weekends (I think 3 or 4 weekends per section) and tunneled underneath the street for our new Metro subway. Traffic flowed during the week and afterwards on metal plates, steel beams and concrete supports. Sorry, but even to the layman, this seems like a total design and construction debacle of the highest order. And what Federal or State of Florida agency or agencies had oversight on this project?
10
The water table is very close to the surface there. A tunnel, if it could be structurally sound, would need to be constantly pumped out.
15
In addition to what John says, a tunnel is an obscured chokepoint, more likely to attract crime that an open air bridge. If I were a female undergraduate walking home late at night, I would prefer to be visible rather than invisible to public monitoring.
1
My guess is that the water table here is a few feet below the surface, if that. This part of the Tamiami Trail , SW 8th Street, near FIU, used to be part of the Everglades, mostly a shallow river. it is very likely filled land. I can't think of a single tunnel in Miami, but maybe someone else can.
1
Sounds like criminal prosecution should be in order, but in situations like this no one ever goes to jail.
12
With attitudes like yours out there, it's no wonder that defensive medicine drives up the cost of healthcare in our country. Mistakes aren't crimes.
1
Criminal negligence is a crime.
1
When the mistakes result from gross negligence and lives are lost, then, yes, those mistakes are criminal.
1
The chairman of the safety board, Robert L. Sumwalt, said Friday that part of the inquiry would examine why there was not a central support beam to hold up the bridge.
If nothing else, a temporary central support until the suspension segment of bridge construction was completed would gone a long way toward minimizing the risk of failure.
15
Based on the surveillance video that shows the failure in progress, it looks as if the machinery and workers were doing something at the north end of the bridge (nearer the canal) when something snapped, causing the bridge to fold at that point and drop to the roadway. I'm curious what the large truck crane (apparently marked "Merchant" on the boom) was doing at the moment of failure and why it seems to have left the scene by the time the first rescue vehicles arrived.
19
Shepherd Smith had an eyewitness on the phone in the hour after it happened and the guy said the bigger crane had something held over the bridge and that what it was holding snapped free and fell onto the bridge. They then showed a picture showing the hook at the end of the cable and it looked bent open like it gave way.
2
The design, the entire concept, are about spending 14 million dollars! That was the purpose. Since it's "economic recovery" grants, as long as the money is spent, whether there is value for money, or even if it makes any sense, who cares? Not so surprising, this formula means competence itself goes out the window.
The engineers are at the wet edge of what they can do but the Highway Dept, County gov know nothing about it.
Many posts, "give us more $$ for infrastructure". Unbelievable. Too much money and too little sense get you this.
13
Seeing the Bay Bridge built, the tower is built first and the the roadway is suspended from the tower. the very thin concrete bridge with a heavy truss WITHOUT the suspension mechanism seems a little presumptuous...
12
When I visited Moscow I was impressed with how they handled this problem. They had wide pedestrian tunnels that went UNDER the multi-lane highways. These tunnels doubled as marketplaces, with exactly the kind of tiny business stalls within the walls that there once were in New York in a passageway connecting Grand Central Station to 45th Street. The Moscow tunnels were wider, they were cold, damp and not too attractive, but you could buy reading glasses, sim cards for your cell phone, and flowers for your girlfriend under there. I felt right at home!
12
Why not pedestrian underpasses/marketplaces in NYC I've long wondered. For at least four decades they have been common in Germany (think Karlsplatz, Munich). By ten years ago, they were found in Kiev where some of the stores were the trendiest in town.
In Florida, which is basically a giant sandbar, the water table is high and the ground is riddled with sinkholes. You can't build tunnels there. The more probable solution is monorails, above-ground transportation systems. Not cheap, but below-ground is impossible.
3
It's important to have safety standards, to make them better, and to follow them.
4
Doesn't the Trump administration think regulations are not necessary?
Sometimes things look great in theory and on paper. But this is the real world, did they expect the unexpected?
3
Civil and mechanical engineering are mature disciplines. Catastrophes are rare.
As someone else (not me) posted, this looks like a management problem. The center pylon should have been installed first.
We have a very large cable stayed bridge here in the San Francisco Bay Area: the eastern span of the Bay Bridge. So I ask: why was the tower not put up first if the bridge needs it to stay up? Or a support put in the median to support it while the tower is built? I grew up in the construction business and learned that fast and right are frequently incompatible.
43
"The chairman of the N.T.S.B., Robert L. Sumwalt, said Friday that part of the safety board’s investigation would examine why there was not a central support beam to hold up the bridge."
This is the main question. A temporary pier or support (even one of those "lift trucks") could be set where the median is. This would have been in the way when the bridge was moved into place because beams connected the front and rear of the "lift trucks". 174 feet and 950 tons of concrete looks precarious when only supported at each end. And not sure if it makes a difference, but the trusses have an asymmetrical "W" pattern which doesn't seem like it would be as strong. A video from street surveillance showed the bridge first broke at the top of the first diagonal canopy support.
Condolences to friends and families of the victims.
9
As we engineers weigh in, I'll add that if the trusses supporting the roof are required, why wasn't there some support for the walkway, since that walkway was taking the load of the roof, without its own truss system to keep itself up. We've learned that there was supposed to be a support system from above provided by a tower from which steel cables would take this weight. Did the builders not get a memo to not install the walkway without this overhead support? Or were they overcome by magic thinking, in the interest of speed and "efficiency", to just do a quick test, as if the laws of physics won't apply if no ones looking? Extremely irresponsible.
61
I love it when a seasoned engineer, points out what should be abundantly obvious to any first year student. And even if the roof didn't theoretically need any support, why wouldn't you install something to take the weight, until the ROAD could be closed, until the structure was carrying the weight as is should. I do love your memo comment, because it seems that someone didn't get the memo.
I'm no engineer, but I do understand how the structures loads are spread out along the load bearing infrastructure so that no one point is carrying to much weight. Imagine if the company that built this actually built skyscrapers, imagine the numbers killed, in a full on building collapse, where the building doesn't fall in on itself. There is a residential building in San Francisco that is leaning, we may get to see physics at work.
10
Anyone who has had structural damage to his home knows loads are something to be managed else bad things start happening. It's frightening that so basic a concept was somehow missing from those equations.
10
Is that the one where people paid millions for their condos?
I agree that it is too early to comment on design/construction failures in the absence of any hard evidence. But it is just too tempting to speculate and so, I'm putting my two cents in, as an architect and in all modesty.
First of all, I do not understand why this design can be called "elegant" or something like that. For a cable-stayed bridge, the deck looks extremely clumsy, especially with a roof also made out of solid concrete (as opposed to a light metal structure). And this seems to be, secondly, the result of a really remarkable concept: It calls for building a deck that can carry its own weight until the tower and stay cables are in place, at which point it no longer has to carry its own weight, i.e. it's overdesigned for the rest of its life (yes, pedestrian traffic will be added as a load, but the cables should be able to take care of that, too).
My question to the engineers: Does this design idea make any sense? Does one really need 8 years to come up with something like this?
59
I'm sure that there was some milking of the contract, in terms of the design phase. And there is probably some corners being cut by the builder as well. I was a contracting officer for GSA, I will omit the state. Many times we would have to meet with a builder of a state office building for instance, we would meet to discuss why certain aspects of the building weren't code, or where the roof leaked, because flashing that was in the building plans that were submitted, was cut because the builder was trying to either meet the dead line, or was just trying to save money. Thinking, out of sight out of mind kind of thing. So I've seen this kind of thing before, and I'm sure that the designer of the walkway, took into account loads that the structure would be under until the cables were installed to take up the weight.
This is why, low bidder isn't always the best option.
16
I know enough about concrete design to be dangerous (student) so I may be very, very wrong, but isn’t the roof made out of concrete because it is supporting the compressive stress (as if the entire thing is a beam)? This document is why I have that impression. https://news.fiu.edu/wp-content/uploads/17703_EXT_FIU_Bridge_Move_Fact_S...
5
Yes, low bidder isn't always the best option. I remember when working in Europe , it was pointed out to me that low bid doesn't automatically get the job awarded. The bid is reviewed by an independant bureau and if found to be "too low" to reasonably conform to regs. etc., it is thrown out and the next low bid is considered. Same is true for review of design (architect) Was any of that done here ?
7
RIP to those who lost their lives in this tragic event. I am just curious why the highway below wasn't closed and traffic diverted after they discovered the loose cables?
22
I am struggling with why they cannot get under the debris to reach victims - no access to the proper equipment?
9
There are several TONS of debris - concrete & steel - on top of the cars.
The mass of debris is unstable and shifts while equipment is trying to remove it bit by bit. (Go see a video on the Miami Herald)
Not exactly a 'grab a shovel and dig down' situation
It is slowpainstaking work to avoid getting workers injured or killed
Further the debris has to be disturbed as little as possible for investigators to try to determine why it collapsed.
The people under the debris are dead - a few days make no difference to them
24
Thanks for explaining. However, a few days will make a difference for the deceased, considering it'll be in the 80's in Miami for days. I would think that recovering the bodies before they decompose in the heat would be the highest priority. We have legal and moral obligations to treat the dead with dignity, and the thought of letting bodies rot in the Florida heat because it's more important to determine why the bridge collapsed doesn't sit right. And probably doesn't sit right with any of their family members either, especially those who are waiting for verification whether their family members are under there or not.
4
If they were working with something this massive, it was important that they have safety equipment present commensurate with the project to deal with potential accidents - and several tons of debris. I suspect that one eventual conclusion - whatever the cause(s) - will be that in the future, consideration of the worst possible situations will play a much bigger role in approving construction plans in Florida. No one will trust the current review processes.
Of course this is not about "grabbing a shovel": this was a 14 million dollar project. [Note: people were rescued - still alive - after major earthquake damage caused California bridge and road collapses] As Lori Sirianni points out - delay does matter. to families and friends of the missing, and to what they will eventually see.
$0.02 from an armchair engineer who reads a lot about failures...
Having studied the photos and the artist drawings of the completed bridge, it appears that we are looking at a half-bridge. The column by the water (by the green crane) was the center support and future cable tower. The diagonal between the upper and lower deck align with the planned tower cables and end in humps on the top that appear to have connection points on them for the cables. The other half of the bridge was to continue over the water.
My amateur guess is that the failure started when the lower deck detached from the center portion. I base this on the photo showing the left end flat on the ground while the other end angles up to the support to which it is still connected along with the way the upper deck at the left appears to have been pulled down by the lower deck.
Whether that failure had to do with the reported tensioning of unexpectedly loose cables will, I'm sure, be a focus of investigators.
A big question requiring an answer is: when you are building a "first of it's kind" structure and find, if Rubio's reports are correct, that critical components are "unexpectedly loose", why wasn't the first step to immediately clear the area and block traffic until the cause was determined and corrected?
112
You are on point for a number of issues.
You need to review the history of the bridge designer AND the construction company. This was not a "first of it's [sic] kind." According to a comment by the director of the N. T. S. B. team: "The chairman of the safety board, Robert L. Sumwalt, said Friday that part of the inquiry would examine why there was not a central support beam to hold up the bridge." The very first thing I questioned when I saw the installation and the results.
A "bridge" was built over South Dixie Highway - U.S. 1 south from the end of I-95 to Key West - for the University of Miami - Coral Gables area. Steel. Mostly fabricated off-site. No problems.
The bridge was not complete. Was not to be completed until some date in 2019. The first question that should be asked: Why was load testing going on with active traffic below.
Might cost you $0.03 to take the time to logon to the Miami Herald and keep up to date on what surely will be a major conflict between at least three parties. Do some research on the contractor and don't forget the County Government and how business is done down here.
9
Alas, so things haven't changed in Miami Dade County? About twenty years ago the company I worked for got taken by MDC. I blocked a future deal based on past experience. It was the only time I took such a step in ten years.
Excellent question and comment!
I remember when Columbia University built a pedestrian bridge over Amsterdam Avenue, the concrete was tested and found to be inadequate. The entire structure had to be torn down and the rebuilt from scratch. I wonder if the concrete on this FIU bridge was tested before deploying it over 8th Street.
43
Structures are most unstable when they are under construction. From what I understand this bridge was still under construction. All the pieces, including connections, were probably not yet in place. That the public was allowed to walk and drive under this 900 ton “work in progress” is a question that needs to be answered.
125
Aside from any possible criminal prosecution (highly unlikely but still possible), the amount and scope of civil lawsuits are going to be staggering. Has anyone claimed responsibility yet for this unnecessary debacle and needless loss of life?
1
WOW.. Rubio's comments were completely inappropriate regarding the cables. It is a labor intensive effort to investigate and understand why the bridge failed. At any point of design and construction something...anything could have gone wrong. Only when everything has been investigated should Rubio be opening his mouth!!! Tragedy for all involved..but luckily we have investigative resources necessary in finding the scientific cause and arriving at the real conclusion for this tragic failure. .
12
Tood bad, Rubio was not driving under the Bridge. He would not be missed.
Yeah, why waste money on our decaying infrastructure when we can send more bombs to the Middle East or spend another trillion on the barely flying F-35.
30
Agreed, except this wasn't decaying infrastructure.
16
Yeah, I bet some Radical Islamic terrorist put a spell on that bridge. Yeah, that's it. Alex Jones sez so.
Earth to Apache Junction: this was new, improved infrastructure. Whether we spent five cents or five trillion in 'the Middle East' is about as relevant as the price of a bowl of posole in Albuquerque. It failed, while still under construction, for reasons as yet undetermined.
And its failure is scant pretext for utterly irrelevant, wholly inappropriate sociopolitical commentary. At least let the bodies cool before you begin to mouth off.
5
This was a new bridge. How was it decaying?
The structure wasn't really "for" pedestrians, though they would be using it. Climbing up onto this bridge, crossing above the motor fumes, and down the other side, really isn't what people need to walk about their city. This design is about *not infering with auto traffic*. They didn't want to narrow the lanes or do anything else to slow the cars--not on a highway, but an urban street! They didn't want to properly build up the ground-level pedestrian infrastructure, even though that would likely have been cheaper. This whole project, from its original conception to the "instant" construction approach with no lengthy closure, was about keeping the cars zooming.
97
"This whole project, from its original conception to the "instant" construction approach with no lengthy closure, was about keeping the cars zooming." Yes, and your problem with that belongs somewhere else. If you look at the history of Sweetwater, the campus, and traffic patterns, this solution was eminently sensible. Maybe in a hundred years, they can do a "Big Dig" and bury the traffic and plant flowers along a ground level pedestrian walkway, but I refer you to the collapse of the ceiling of the Big Dig that also resulted in fatalities.
5
No digging. Slow the cars, and build the city to prioritize human beings, like those residing and going to school on either side of this street.
1
Spot on. Millions where a pedestrian crosswalk already exists. More human sacrifice to the holy automobile.
2
Is it possible that corners were "cut" in the concrete mix?
As was stated the majority of the input is not from experts in the construction industry.
3
With all due respect to the excellent reporting by the NYT, today's Miami Herald has a very detailed breakdown of the circumstances surrounding the design, construction and elevating of the bridge which hints at possible causes.
13
Thank goodness so many readers have already diagnosed what caused the collapse without even a post-inspection of the bridge. This will save the state millions in hiring other so-called experts.
As for the loss of human life what can you say? Absolutely tragic and devastating.
17
Ugh. Don't be so "grumpy". The comments are - for the most part - discourse among and between educated and/or otherwise informed individuals.
The apparatus moving the bridge into position had two ‘trucks’ connected fore and aft by tie beams. This was what prevented falsework (cribbing, temporary support) from being located in the center and insured that the deck had to support itself from the start, or else. We’ve seen else. It could just as easily have fallen as the jacks were removed. Flat out hubris motivated by unwillingness to block one traffic lane for a few months until the rest of the tower-suspended structure could come along. Hubris in covering the concrete beams all over with FIU banners, so that there was no chance of visually finding developing cracks. Hubris in wanting an outsize, monumental walk way to advertise the university’s specialty - just this type of structure! Even if the calculations and the detail construction were correct, the concept that this span could self-support without the suspension cables meant intentional expensive overbuilding - precisely what the ABC concept might reduce. Beyond this, there is the issue of lack of state-mandated secondary inspection, the post-tensioning issues, and maybe other stuff. Horrible.
25
Why exactly was a speedway needed alongside a university campus? As elsewhere but particularly in the south, the right of drivers not to slow down or stop for pedestrians is held to be paramount. When pedestrians die, build a pedestrian bridge at great expense, so cars can continue to reign below. Was the bridge even accessible to the handicapped or the elderly, who can cross at street level but can't easily get up stairs?
141
The road was there first.
8
Mike:
There is no "speedway" alongside the campus. It grew from a two-lane road the people took to go from Miami to the West Coast of the state and simply grew to 6-lane street with two additional turn lanes.
Yes, having lived in San Francisco and driven around most of Northern California, I support the cross-walk protocol in California. But this is what it is and is a highly traveled roadway.
The bridge was not to be completed until sometime in 2019. There would have been "towers" at each end, fully accessible for handicapped through the use of elevators. Read the specs for the bridge, with its planned WiFi, lounge areas and extended access across the canal on the west side.
Learn about that which you wish to criticize.
8
Roadways don't "simply grow," Lloyd. They cost money. People make decisions about when and where and how. Sometimes tragically short-sighted decisions.
4
It seems to me that the structure as constructed was okay to support it's own weight. The cables would be needed at a later stage when the rest of the bridge was constructed, prior to opening the bridge for pedestrian loads. The very fact that the structure was fine for five days indicates that there were no issues with the structure itself. Any issues in the strength of the structure would have been conspicuous. Typically in concrete structures strength issues manifest as excessive sagging and/or cracks in the concrete. I haven't seen any reports detailing such issues. I have seen the footage of the actual collapse. The suddenness with which the structure collapsed leads me to believe that there was a sudden loss in capacity, also referred to as a brittle failure. Loss of steel reinforcement leads to brittle failure in concrete structures. Reports seem to indicate that the structure was post-tensioned (PT). PT provides tremendous tensile capacity to concrete. However, loss of PT can lead to a sudden catastrophic reduction in strength as concrete by itself has virtually no resistance to tensile stresses. Based on Sen. Rubio's tweet, I think they were working on adjusting the PT on this bridge when the failure initiated. There are several photos that show a strand jack attached to a PT bar on the collapsed bridge (I believe failure initiated here). It's quite possible that the PT bar was overstressed or there was a failure of the PT anchor leading to a sudden, brittle failure.
41
Thank you for your comment which is clearly based on experience. Would it be normal in these sort of constructions to have a temporary support in the center of the spans prior to adjusting the PT?
5
An intermediate support wouldn't have prevented collapse simply because an intermediate support was never assumed in the design. The presence of an interior support would govern the location of PT tendons. The structure as it was constructed required PT tendons to be placed in the bottom slab where tensile stresses exist. An intermediate support would modify the behavior and redirect the tensile stresses to the top slab over the location of the interior support. The behavior between a simple span (as constructed) is vastly different from a two-span continuous configuration (as would be the case of an interior support). The intermediate support would make sense if and only if the two-span configuration was assumed and designed for i.e., PT tendons provided in locations of expected tensile stresses.
9
Where are the cables that were being tensioned? As I understand it, the tower and cables from which the bridge would be suspended were not yet in place.
As an architect i assumed that the final design had a support between the east and west lanes of traffic. reducing the span in half greatly reduces the cost. No, It seems that they wanted to spend as much as they possibly could on a pedestrian footbridge: A 20 story tower support with cables for a pedestrian footbridge? A mindless showpiece a la Calatrava's transit hub in NYC.
30
My heart goes out to these suffering families.
And all my love and respect to the first responders. Stay safe.
~ 9/11 family member
143
So very sad; I read something about 9/11 this morning and the memories flooded back with such force I was beyond angry again.
My daughter was a block away that terrible day, and it took hours to get to her, know she was safe, and get her home, even though she was enveloped in the debris cloud, as the towers collapsed.
She suffers to this day from serious respiratory issues, which will never go away.
Lately I feel terribly disappointed with our way of life here in America; we seem to be on some kind of road to nowhere, and no exits back to normalcy.
1
If in fact they were doing testing with the road open I wonder if there are any regulations against it. But remember my fellow Americans Trump is against regulations and brags about eliminating them. Let this be a lesson regulations for the most part come out of incidents like this. In aviation we call it tomb stone regulations.
188
How in the world did you decide this has ANYTHING to do with Trump?
It looks like the concrete didn't cure properly. When concrete fails it cracks, not crumbles. Here it crumbled like a crushed sugar-cube into hundreds of tiny pieces. A concrete failure usually has a couple of big cracks and the pieces still hold together.
11
This story sure is bringing out the armchair engineers and construction experts to the comments section.
11
Here in Utah our DOT has built a number of bridges in this manner with excellent results. Don't blame the technique, which is very citizen friendly and helpful to keep traffic moving almost throughout the construction process. There was clearly an engineering failure, either computational or commonsenseical. Clearly the span itself was too heavy and too weak to support its own weight without the trusses, while the method required exactly that. Reminds me, on a super big scale, of the carpenter's saying, "measure twice, cut once." or like they say in third grade arithmetic class, "check your results. "
11
Hard to tell from the pictures, but it looked like the proverbial "bridge to nowhere." That 14 million could have paid for a bunch of scholarships. The students could have waited for the light to change to cross the intersection, there was already a traffic light there.
Beyond the tragedy, surely this wasn't the best allocation of resources? I suspect similar things are happening at other campuses in Florida where because of population growth large universities that were practically unheard of a few decades ago have seemingly sprung into existence overnight, the proof of their size being their big time college football teams.
12
Numerous stories have detailed the fact that the bridge leads to a neighborhood where approximately 4,000 of the college's students live. It provides access to more than just the lot visible in the photo.
3
Civil Engineer. I've worked on a lot of phased construction such as this. I don't know this project, but I can't fathom why they didn't use falsework to support the center of the bridge while under construction. The NTSB will figure it out.
40
CE here too, like you I acknowledge that I don't know this project. But, we both understand that this portion of the structure, alone, as is, should be strong enough to support itself safely, indefinitely. If not, it needs temporary support until the entire system is in place. I await the NTSB findings.
Funny, you and I, two people with expertise, are reluctant to jump to conclusions, while an endless stream of commenters seem absolutely certain they know exactly what happened here.
1
I have read that this accelerated design/installation method has been actively promoted by the university for some time and that this pedestrian bridge was intended to be a showcase example of it. I would suggest that that's what became the main consideration, above its primary purpose to support the weight of pedestrians above a busy road.
5
I recently read that much of modern Istanbul was constructed with concrete mixed with sea water, a major act of lunacy which set into play a major disaster when a major earthquake strikes this Turkish megapolis again. The highly friable quality of the concrete in the Florida bridge disaster also suggests the use of mediocre building materials, all used in a spirit of cutting corners and maximizing profits at the expense of innocent bystanders' lives....
9
So the NTSB is just staring its investigation and you've already concluded that it was the concrete along with cost cutting measures. Amazing.
15
Prior to the collapse, FIU triumphantly tweeted, “FIU is about building bridges and student safety. This project accomplishes our mission beautifully.” This bring to mind another tragedy from over 100 years ago, the Titanic; engineering steeped in hubris often ends with calamitous outcome.
25
Hubris played little role in the sinking of the Titanic. People who think so are confusing spin and marketing talk for reality. No one in the know thought the Titanic was "unsinkable" -- that was an advertising slogan. The ship's design and construction put glitz and money before safety. Its sister ship almost sank from a simple grounding incident in harbor, so shoddy was the construction.
The claim of "hubris" was made by the shipping line and the British insurance industry. You see, unlike negligence, "hubris" is not a tort. You can't sue for it. So many millionaire families suffered losses that their expensive lawyers would have destroyed the British passenger ship industry has the truth been admitted. Hence the legend.
Perhaps we will eventually learn the truth of this latest disaster. But not for months. I'll read no more about it until an independent report comes out.
5
"Hubris played little role in the sinking of the Titanic."
Like, it wasn't speeding on a dark night in a sea laced with icebergs?
Like, the lack of lifeboats wasn't evidence that the engineers and the shipping line didn't think that the ship was "unsinkable"? Do you have a personal problem with the use of the word "hubris"? I see hubris in 1912, I see hubris in the Big Dig ceiling collapse in Boston, and I see the potential for failures here brought about by shall we say arrogance?
1
I've seen this same remark in several news stories t-- the bridge collapsed a week "after it was driven into its perpendicular position across the road by a rig."
Why does it not say "driven into its horizontal position across the road"? Is there anyone who can explain this? Thanks.
5
Perhaps because it's perpendicular to the streets it connects.
5
Maybe "perpendicular" refers to the angle between the horizontal bridge and vertical columns on the left and right side of the street? Not sure.. I'm definitely not an engineer but at first glance I found it odd as well.
1
Bridges cross roads at perpendicular angles to the road.
1
I was wondering why a footbridge would be this heavy - but now that I've seen the video of the model for an "iconic bridge", it was way overdesigned - not in terms of safety, but in extra features that were unnecessary: why do you need all that seating as if you were in at a cafe, and thus require an overhang for bad weather and fans when it's too hot ? You are just crossing a highway! This is not the direct reason for the disaster, but a sign of the hubris of the project that led to attempting to do too much while forgetting the essential. Like putting up half the bridge without having what appears to be sufficient support, in order to show how fast the project has advanced ?
219
Ignoring the aesthetic and community concerns for a moment, any bridge in Florida and especially Broward & Miami-Dade Counties (a High-Velocity Hurricane Zone) is going to be extra heavy & expensive simply because it has to survive 140+ MPH per hour sustained winds without breaking.
You will notice that the traffic lights in the picture attached to this story are all mounted on poles, and clamped twice sideways against them. This is much more expensive than hanging them from wires, but keeps them from detaching & flying.
Pretty much all road infrastructure in this area is designed to survive a Category 5 hurricane. No one wants to have to delay aid or evacuation because they could not clear a roadway without bringing in heavy-lifting equipment.
(And it rains pretty much every day in South Florida during the rainy season. I have been to Florida International University's campus, and driven through where this bridge was. While FIU has at least some covered walkways around their Student/Graham Center facility, most of most campuses tend not to be, and the exact extent varies from campus to campus.)
My father built dams for the Corps of Engineers and was their 'concrete specialist'. He constantly monitored their contractors to make sure they used the right formula of cement (a powder) water, sand and gravel. Too little cement (which was the most costly ingredient) made a structure weak, but saved the contractor money.
20
It's hard to believe that collapse of a project of this magnitude ($14M) would be a design error. My husband, an engineer, says that it was a construction error - how those cables were "tightened".
24
My God! Even to the untrained eyes, the construction site looks like a Mickey-Mouse do-it-yourself project. They put the cart before the horse. There was nothing to brace the 170 ton, 174 feet concrete structure. Yet they did nothing to protect the public.
12
Just awful and another reason for campaign finance reform, this construction company has given heavily to Miami politicians (mostly Republicans) for ages and keeps getting awarded huge contracts.
Florida is ground zero for developers buying elected officials (this is why project after project is built that violates zoning, voter referendums, etc.). We need campaign reform, these elected officials don't care about citizens or construction workers or people who drive around this area, they only care about the next fat check from the developers.
60
On Tuesday I was in Home Depot but was blocked from an aisle because a forklift was there. But if I was in Florida I could have driven under a 900 ton bridge whose cables were being adjusted??!!
283
Let's see how quickly some type of new laws are enacted regarding this type of construction/installation.
Kill 17 kids with an AR-15 and politicians don't do anything.
45
I wouldn't count on new laws aka "regulations" being quickly enacted regarding this construction. We're living in the era of Trump: kill 16 regulations for every new one.
4
I have followed this heartbreaking event closely and am so deeply sorry for the families of deceased loved ones and for those who were gravely injured in this collapse. I can't get two thoughts out of my mind. It seems this structure is an incredibly expensive and massive 'answer' to a pedestrian crossing need. The need became evident due to another tragic pedestrian death, but in lean times and with so much infrastructure demand nationally, I question the wisdom of the expense of this massive structure for walkers/cyclists. Also, isn't ABC best intended for replacement situations, where an existing old bridge is compromised and where the mobility of the public would be threatened by traditional on-site construction? I hope the enthusiasm for and embrace of this newer method doesn't blind decisionmakers to its highest and best use. It is not an excuse for over-employing it or over-engineering an otherwise simple project because of ABC's availability and promise.
9
The intuition of a five year old playing with blocks would comprehend the structural instability of two pylons supporting such a heavy span. Form follows function. From all appearances, FIU leveraged this bridge as a marketing tool, a project that would function both as a recruitment and fundraising coup. I wonder if this tragedy isn't the result of hunger for growth evident in higher education, where competition for students and funding rages unabated.
20
"From all appearances, FIU leveraged this bridge as a marketing tool, a project that would function both as a recruitment and fundraising coup."
Really? You can tell by looking at the bridge that FIU "leveraged this bridge as a marketing tool" and a "fundraising coup"? It was a pedestrian bridge, not a football stadium. I will donate $100 to FIU for every student you can find who considered this, or any, bridge, as a factor in deciding which school to attend.
Get a grip on yourself.
3
Look closely, the failure was not the pylons, it was in the web of the truss at the first panel point away from the canal.
1
GMooG,
I agreed with your post and was ready to add to your offer of $100, until I saw the YouTube video from Tony a few comments below. Now, I am not sure.
Progress?
Assyrians-Anatolians-Greeks built a 43 ft+/- bridge over a river in now what is Turkey. It is around 2,868 years old and still in use.
The Romans built the Pons Fabricius over the Tiber in Rome. It 203 ft long and 18 ft wide. It is 2,080 years old and still in daily use.
Further there are still many many Roman bridges in use all over the mid-east and Europe. Pons Fabricius is merely the oldest one left.
The Americans aim to build foot bridge (like these other 2) with the goal of it lasting 100 years. (Guess no one knows how to really build things that last anymore)
The American bridge lasted less than 6 days.
What is wrong with this picture?
325
american ingenuity at its current state.
9
The major reason you can cite these long lasting Roman bridges, is that all the other ones collapsed so long ago that we don't remember. All structures are least safe during construction, traditionally Canadian engineers, particularly from Quebec, are given an iron ring on graduation, to remind them of the workers who died building the first attempt at the Quebec City Bridge because the design was only stable once completed.
13
With far lesson regulation over the next 3 years, the picture may be very bleak.
7
"The bridge had been the culmination of eight years of planning and work . . ." This fiasco too EIGHT years to plan? Like, what's the rush?
41
It sounds like Mark Rosenberg, university president, Senator Rubio and Deputy Mayor Maurice Kamp haven’t had time to synchronize their stories yet. “On Friday, the authorities declined to answer questions about why the roadway under the bridge was not closed during testing, and Maurice Kemp, a deputy mayor of Miami-Dade County, said they had not even confirmed whether any testing was happening. ‘Obviously, everybody is in shock here,’ said Mr. Rosenberg, who had been a public champion of the bridge project.” You people may be in shock, but it’s nothing compared to the shock experienced by people driving cars under the bridge during the collapse.
36
I regret that I did not include my condolences to the families ,
friends and compatriots of those who died in this terrible event.
13
I have never seen so much crumbly concrete. No clean breaks. Strange...
23
I'll bet the coverup is outrunning the investigations on this.
24
Here's a video of the bridge as proposed. It shows a central support and cable stays. How the engineers could expect a span of this length to be supported by tensioning cables is incomprehensible.
https://www.youtube.com/watch?v=5Y_71L35CvM
10
Tony, it is a cable-stayed bridge, https://en.wikipedia.org/wiki/Cable-stayed_bridge so the bridge deck where the traffic runs is supported by cables from the central mast. The cables are in tension, as all cables are. Tension makes better use of the material. because tension pulling on the ends is stabilizing.
1
Were sections of the bridge incomplete and covered over? I'm reminded of a ship in construction circa. 1983 at the Bath Iron Works that sank because someone put a piece of cardboard over an incomplete section of the hull. The hull was subsequently painted and launched. The hull sank.
59
The article says the project was done quickly, perhaps too quickly to have the time to do all the bolts, welding and riveting needed.
2
Why do people feel compelled to fantasize about a possible cause, no matter how unlikely or uncumbered by knowledge or facts?
Having been around construction though not an engineer myself (several family members are Civil Engineers), I suspect the problem has to do with the concrete used to make the bridge, that when they tensioned it caused it to fail by putting torsion on it. Usually with concrete failing like this, there are several common causes IME: 1)the concrete did not have proper reinforcment in it, didn't use enough rebar and/or didn't place it right 2)the concrete was not allowed enough time to cure properly before being put under load/tension (not sure when this bridge was built, since it was prefab, not poured in place) or 3)the concrete used was not of the proper mix for the kind of load it would need to take. Concrete is supposed to be tested and certified that it is the right mix for the thing being done, but who knows? Supposedly the contractor in this case was known for shoddy work, which makes me think it even more likely it was something with the concrete. Given that the bridge was not under any load other than its own weight, a span bridge like this should have been able to stay up with no other load on it.
16
The bridge that collapsed was designed to be SUPPORTED by cable stays tied to a tower neither of which exist. An absolutely brain dead and risky way to build a bridge. Normal construction would require building the SUPPORT STRUCTURE before building the thing which is to be supported. They built the bridge backwards and no one should be surprised it did not work out. "Accelerated construction" sounds an awful lot like sacrificing safety for profit....
228
Well said Tim. The alternative would have been to place a temporary support somewhere under the span. There's a thin median in the roadway, or possibly a lane of traffic would have to be closed. The size of the plates on the roof of the span, which align then to the diagonal supports between the roof and deck, suggests high forces were expected to be in the cables coming down from the central tower to hold up the span. Why anyone would think it OK to put up the span without the tower and support cables and without any temporary supports to make up for their absence is beyond me.
36
My first thought when I heard about this is how Trump wants to streamline infrastructure projects and how he wants to do it....
82
My own first thought is that somebody is going to have some explaining to do, although it is not immediately evident to me why Trump should be that somebody.
Hindsight is 2020.
The way this bridge is designed, the bridge structure is not fully stabilized until all of the components are completed. In other words, until the stairway structures are built on either side and "tied-in" to the bridge construction, the bridge structure is not completely stabilized.
Senator Rubio indicted some cables were loose. After looking closely at pictures at the end of the structure, this appears to be a post tension structure. That means huge steel strand cables embedded in the concrete walkway of the bridge provide an enormous amount of strength to keep the bridge in tension, but they must be mechanically tightened. Not sure here, but the cables were probably tightened before the bridge was put in place, but not retightened after the bridge was moved and put in place.
A simple way to have prevented this collapse was leaving shoring in place under the midpoint of the bridge (in the roadway median) until construction was finalized and the bridge completely stabilized.
49
I’m a structural Engineer. The cable being loose caused the bridge to collapse. It’s the cable fastener which was the responsibility of the GC, the inspector, and the cable fastener company’s design. Flaws are found in most projects and these 3 groups are expected by the owner of the project (the university) to catch flaws such as this and make adjustments.
68
I assume you also agree that during this phase of construction and testing (prior to the main cable stay support system even being erected) the roadway below should not have been opened to traffic.
46
As a mechanical PE, I question if any amount of tightening of the horizontal tensioning cables could account for the fact that the vertical support cables were not in place, nor was their absence otherwise accounted for with temporary shoring. The design calls for a 109-ft central pylon with 5 support cables for each of the two counterbalancing spans, not yet in place when the first span came down.
22
Roger - The final design would have to support more than the weight of the span; it would also need to withstand hurricane force winds, the weight of a crowd of people during peak events, etc. Without seeing the plans, you cannot know whether the central pylon and support cables were necessary to support the weight of the span itself. However, support beams are routinely constructed before the span is in place; it seems unlikely that an experienced group of structural engineers would have diverged from regular practice without an analysis showing that this was feasible. We will see once the investigation is complete.
Accelerated Bridge Construction
The aim of this method is apparently to build off site and then put into place so that traffic congestion at the site is minimized .
Accelerated anything means as quickly as possible. A concept that
needs a lot more study .
138
I don't think the word "accelerated" should ever be part of any conversation or consideration in construction or engineering projects - EVER. Safety should be the key, not speed.
28
ABC -- Accelerated Bridge Construction -- has been used in thousands of bridge projects. I don't recall any other collapse in any way attributed to this methodology. It is as strong, even stronger, than classical methods. What was lacking here was appropriate engineering review.
The "accelerated" has to do with how long highways need to be closed. The replacement for the eastern half of the SF Bay bridge is but one example of its use, and so benefitted the bridge's users without any danger as a result of that method.
5
Marge, I'm sorry you don't like the word 'accelerated,' but it's commonly used in structural engineering projects. In the olden times, there was only one way to build, well, anything. Nowadays, we have precast systems and construction methodologies that allow minimum interruption to public services. The word 'accelerated' does NOT mean fast and shoddy.
I'm saddened by the number of people who don't understand how all our buildings, roads, and bridges are designed and constructed, yet feel they are qualified to criticize the words engineers use to describe a process.
4
While I realize that the burning question is what caused this tragedy, I can only imagine the anguish and pain family members, friends and rescue/recovery professionals are feeling for those still trapped in those 8 automobiles. Reading the quote from Miami-Dade Police Department spokesman Alvaro Zabaleta “The fact that we know that there are bodies down there and we can’t get to them, it’s just horrible,” is haunting and heartbreaking. I can't even begin to understand their grief and sorrow.
59
I wouldn't worry; I'm sure the construction company and university bigwigs are sending out lots of thoughts and prayers to the victims.
10
That does no good, Wally.
5
I agree jb. With all due respect Mr. Wolf, glib nor sarcastic humor helps no one. Things are painful enough without adding more bite to the mix.
5
Very sad. The traffic needed to be diverted (under the bridge) while the bridge was being worked on to tighten its support cables which had loosened... the bridge collapsed while it was being worked on.
43
The list of tragic mistakes made here appears to be long and obvious to most with basic engineering knowledge. It will be interesting to see if the investigation reveals that concerns expressed by anyone involved were ignored by management and public officials. With engineering disasters ranging from the Space Shuttle to other construction tragedies, good people who follow the rules are often ignored. Management decisions in business are driven by time and money. With government projects, you can add politics and ego to the mix. Unless a safety culture is prioritized, financial considerations will exclusively rule the day. It should be remembered that for every tragic engineering accident like this, there are dozens that are barely averted due to luck.
365
With Trump as president, safety goes right out the window. Profit is all that matters in Trump World.
12
You can also add the problem of the mandate to accept the lowest bidder.
3
"The list of tragic mistakes made here appears to be long and obvious to most with basic engineering knowledge." Seems obvious to me, with no background in engineering, only common sense.
1
A recent quote from Leonor Flores, FIU graduate (1998) and project executive at MCM: "It’s very important for me as a woman and an engineer to be able to promote that to my daughter, because I think women have a different perspective. We’re able to put in an artistic touch and we’re able to build, too.”
Exactly how much did artistic and other priorities, aside from safe pedestrian walkway design, contribute to this disaster?
24
Right, because ugly is the goal and always works. I think you're implying there were other priorities other than safety and functionality, and I think your perspective is ..... not informed. I worked with men all my life in engineering and I can comfortably say many weren't overstressed with engineering problems. Golf, their careers, girls, but not engineering. Not all, but enough. Don't get ahead of yourself.
10
Exactly. When it comes to public safety, the best (fill in the blank) needs to be hired. It doesn't matter the race, gender or religion of the provider.
1
The use of this statement from a female engineer at MCM is hardly fair. Neither is the wild leap to assign potential blame to 'artistic and other priorities'. This executive may have had nothing to do with the FIU bridge.
Is it really too much for people to wait until more information is available about the actual contributors to this tragedy?
11
The design of the bridge seems unusual. Concrete trusses are not commonly used in bridges and the suspension cables and mast were not in place.
11
Quality Products and Service in America in the last 10-15 years has plummeted. Its all about cutting corners and high profits. Every Industry! $$$ We are all in a hurry to put it up without even thinking to test it and now look at what happens. Another thing is we should have been maintaining our country roads and bridges because the further behind we get the slower our economy will grow.
28
I've worked in quality, both in the services and manufacturing industries, for 15 years and what I've experienced is we are the first to see our budget slashed and the first to get blamed when that budget slashing takes its predictable toll.
People like to talk about quality as an abstract concept, but achieving actual quality is hard work, requires dedication and the ability to go against the current, and it costs money. Plus, it's a practice of addressing potential problems before they become actual problems. In this country and society, where people refuse to acknowledge anything that might make them uncomfortable until it's way too late, that isn't the easiest thing to do.
18
Agreed. I am an architect, and every day we are pressured into doing things faster and cheaper. A lot of times the rush results in constantly doing and undoing things, which could have been done much better if the client took a deep breath and focused on the end result.
7
as an architect, i can unequivocally say a pedestrian bridge is one of the simplest structural problems out there.
That this bridge collapsed can only be attributed to incompetence, negligence, or corruption.
434
Or, perhaps, all of the above.
19
As an architect, I'm happy to know that structural engineers design bridges and that you're making a wild assertion that any type of bridge is a simple structure. 7 lane crossings aren't simple structures. A sidewalk is a straight-forward structure. A bridge - rarely simple.
8
Architecture without a structural engineering analysis is just a pretty drawing.
6
There is NO excuse for this engineering debacle. Heads should roll!
140
Heads will roll and suits will be filed and won.
Heads should go to prison.
The major issue seems to be this: why was traffic allowed to cross under a bridge that was still under construction? The central support beam was not in place and they'd removed any temporary support from underneath. Who made that decision and why?
195
In my experienc traffic is routinely allowed to pass beneath bridges, walkways, elevated rail lines, and many other structures under construction. This may have to be reconsidered.
5
Considering it is for pedestrians only, a rope or bamboo or log bridge might have worked as well.
1
@ alive and well, I don’t know who made that decision, but I bet there is a HIGH RANKING cabinet position awaiting them in this admistration.
1
This bridge was actually over-designed, the span is relatively small. It was designed with a center support tower between the east and west bound lanes. Why was there no temporary center support in place after the bridge was rotated into place?
This is a pedestrian overpass, why use a 200 ft concrete tower and cables supporting an equally massive concrete canopy and concrete walkway when a a more modestly scaled steel structure could have been used at a much lower cost?
245
To be clear, this was the first of two sections that were to be put in place. The tower supporting the cable stays would not have been built between the lanes of traffic, but rather at the middle of the completed bridge, at one end of this first section.
3
The renderings I've seen, showing the full bridge, seem to show the central tower between the roadway and the creek, not between the east/west lanes of the road. If true, that suggests that the section that collapsed was only one side of the full bridge. It also suggests that this section was going to remain unsupported by the cable stays/tower for a very long time, until the tower was built and the other half of the bridge was completed. If that's the case, someone must have been quite confident that this section could hold itself up without the cables. On what basis, I wonder?
36
Why was the more expensive less tried method chosen. Someone explains that to me. A "modestly scaled steel structure" would serve the very same purpose.
2
Trying to make sense of this terrible loss, two things confuse me. 1) People are talking about "cables being tightened" during the collapse. In the prototype pictures of the completed bridge I've seen, cables would run down to two expanses from an off-center tower-which had not yet been built. So I wonder what "cables" they were tightening, and attached to what? 2) A bystander in one article I read, who had been near the collapse, said he and his partner, when hearing the sirens, immediately hoped it wasn't the bridge, because he had seen it and thought the side that collapsed looked "very unsafe."
None of the reports I've read are saying this exactly, but it seems that this expanse of bridge was set over a major thoroughfare without the cable support it was designed to have. It was, apparently, obvious even to casual passersby that the expanse appeared unsafe.
Why would anyone decide to allow the roadway to remain open while testing an incomplete expanse that lacked the cable support it was designed to have? Am I too cynical to imagine it seems political?
As in too many a tragic story, follow the money.
203
The "cables being tightened" that have been reported would have been the post-tensioning cables in the concrete deck of the bridge. Presumably the plan was that these cable would provide sufficient support for the bridge until such time as the central tower and cable stays were completed.
It is clear that this plan did not go well, and perhaps a temporary central support should have been in place until the cable stays were in place. Certainly given that traffic was allowed to use the roadway...
25
Yes, I saw the cable tower in the original design as well. That would have picked up the loading of the bridge from the center, instead of from the roadway edges. SO it appears they may have value engineered the center tower and supporting cables out of the structure to create a post and truss bridge. A simple midspan column placed in the roadway median would have prevented this disaster.
7
@Greg Nowell: No, this is incorrect. Look closely at the top of the bridge structure and you can see the attachment points for the cable stays.
1
While I'm sure that the accident scene will be crawling with lawyers soon, I think President Rosenberg should feel comforted that the thinking public knows that this tragedy was not due to actions of the University but that this was a engineering management problem. This disaster does not fall in his wheelhouse.
6
From what I read, it was designed in conjunction with the university research department.
7
Don't be surprised see this incident turn into a stunning case of malfeasance on the part of the highway department, the contractors, and the university. In hindsight, it is quite clear that the bridge should have been fully strength tested in its installed position well before any traffic was allowed to pass underneath. With foresight, engineers in every organization should have had a fail-safe plan for assuring the safety of the bridge, independent of the hype about this trend-setting approach to efficient bridge design and installation.
145
There is no law of physics in our 3-dimensional world that allows for a load-bearing, unsupported structure of this length. Looking at the photo, it's all too obvious that, without a central support (or two), this bridge had no chance of survival. I don't understand how this could have taken 8 years to design. Who is responsible? Who signed off on this glaringly unsound result? My heartfelt condolences to the victims and their families, this should never have been built…
269
If you do a search for "FIU Bridge design" you will see that this was only the first section of the bridge to be placed: the completed bridge was to be twice as long, and have a central tower and cable stay arrangement put in place to hold everything up.
From the pictures of the collapse it is clear that there were post-tensioning cable in the lower deck of the section that was put up to support it until the final cable stays were erected. From the media it sounds like there was a problem with the post-tensioning cables, and that they were being tightened when the collapse occurred.
You are correct that in the meantime there should have been some temporary central support to hold up this span until the final support arrangement were completed.
86
The first sentence of this comment is simply incorrect and uninformed. There is nothing extraordinary about the span of the bridge or the structural concepts it is based on.
Based on what we currently know there was a defect in the post-tensioning cables that gave the bridge the tensile strength it needed to be self-supporting over the span. Whether this was due to engineering or construction is currently unknown but there is no reason whatsoever this structure was not buildable.
Look at pre-collapse photos of the bridge and note the angled members connecting the bridge deck to the roof. The bridge is essentially one large precast concrete truss. Prestressed/post-tensioned concrete truss and girder bridge designs have existed for over 60 years and have been built over spans double the length of the FIU bridge.
20
It’s a suspension bridge with a central cable running across the top, and secondary support cables acting like handrails. If you look at the pictures, it looks like the tension was too high on the main cable, or the concrete footing wasn’t sound, and it collapsed, then pulled down the other side of the bridge.
I think the “central support” mentioned in the article was temporary for the construction phase only.
3