NTSB Animation - Overview of the collapse of the Fern Hollow Bridge
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- Опубликовано: 20 фев 2024
- On Friday, January 28, 2022, about 6:37 a.m. eastern standard time, the Fern Hollow Bridge, which carried Forbes Avenue over the north side of Frick Park in Pittsburgh, Allegheny County, Pennsylvania, experienced a structural failure. As a result, the 447-foot-long bridge fell about 100 feet into the park below. The collapse began when the transverse tie plate on the southwest bridge leg failed due to extensive corrosion and section loss. The corrosion and section loss resulted from clogged drains that caused water to run down bridge legs and accumulate along with debris at the bottom of the legs, which prevented the development of a protective rust layer or patina. Although repeated maintenance and repair recommendations were documented in many inspection reports, the City of Pittsburgh failed to act on them, leading to the deterioration of the fracture-critical transverse tie plate and the structural failure of the bridge. At the time of the collapse, a 2013 New Flyer articulated transit bus, operated by the Port Authority of Allegheny County, and four passenger vehicles were on the bridge. A fifth passenger vehicle drove off the east bridge abutment after the collapse began and came to rest on its roof on the ground below. As a result of the collapse, the bus driver sustained minor injuries and two bus occupants were uninjured. Of the six passenger vehicle occupants, two sustained serious injuries, one sustained a minor injury, two were uninjured, and the injury status of one was unknown.
Anyone who has worked with any material-even an amateur hobbyist in a garage-would understand that this corrosion was way beyond a fatal flaw. It was nothing short of criminal negligence to allow traffic on this disaster.
What's wild is that it seems like it wouldn't have corroded if they just maintained the drains properly. Not great to have a design with that risk built in, but still.
Exactly... that's blatant negligence on the part of the government.
i doubt this would happen even in north korea
@@gatolibero8329 Republicans in government, specifically.
Yeah but the political grifters in government made off with all the money ..
Don't forget to sign and date those tax checks though. good (sµcker) citizens
Unbelievable that a bridge with this amount of damage is allowed to be used by vehicles.
Yet again beurocracy reigns. The state is required by law to inspect bridges. Great. These files get recorded and placed in a file marked bridge inspections.. but thats it. There little to say whos job it is to read the report. Typical council job. No responsibility in the right departments.
these issues can't be fixed by voting
Criminal negligence. Guessing no one was even fired though because government operates outside the law.
"Cough, cough" they preemptively mitigated risk by imposing a posted weight limit - there! And, And, good intentions to repair.
Fixing infrastructure just isn't sexy, so it gets little to no funding until something breaks - at which point it becomes an emergency which opens up Federal assistance and most environmental rules getting set aside (can't say that having a bridge fall into the stream was good for the habitat). I would also say that those bridge deck drains were never maintained, so the Penn DOT maintenance department needs some scrutiny. Properly maintained, this structure should have lasted 100 years, not 49. But we may expect more of the same in America where roads and bridges now must compete with "human" infrastructure, like paid daycare for single working mothers, for funding.
must have been a sorta hard report to write- they're supposed to clearly communicate the reason the bridge collapsed but they probably weren't allowed to say "it collapsed because it rusted through starting almost 20 years ago and you never fixed it"
They said it without explicitly saying it.
In at least some of the CSB's video they don't hold back - the Chevron pipe elbow one, for example.
It’s kind of their job to tell people things like that, but being a government organization they’re required to use lots of fancy words
Did you watch the video? That's exactly what they said but in a technical manner.
NTSB does all reports like this. There are legal factors they have to consider when making these.
That said, they very clearly showed failure due to negligence.
I thought I was looking at green paint on the bridge supports. No, I was seeing the foliage in the background through the rust holes. Inconceivable.
Yeah 5:03 is horrible. I was also confused how moss could be that bright until I realised that was leaves from background foliage.
ruclips.net/video/dTRKCXC0JFg/видео.html
@@krissp8712 and then you notice later in the video that the hole has been there for 8 YEARS!
Me also .
Yes, same. I thought it was unusually green rust. Then my jaw dropped when I realized it was background foliage.
That was criminal neglect. To not act upon the bridge report recommendations should cause the DOT heads to go to jail. Weathering steel does NOT mean NO maintenance forever.
to say nothing about IGNORING multi-year reports and imaging.
Asked why some of those funds were not spent on bridges, Peduto said, “There’s a simple answer. It's because bridges aren't used only by city residents. Bridges are used by people throughout this entire region
@@t2k777 so they did have some money to repair bridges, so were there just bridges that were worse-off than this one that needed attention and they ran out of money? I mean they had almost 15 years of knowing they needed to do something. You telling me there is a 15+ year waiting list for bridge repairs in that states DOT database of bridges? I don't think so. Also, there will be no criminal neglect charges, too many people to blame up the chain of command. The DOT will just payout a bunch of money to the families of those injured and call it a day.
@@t2k777 If anything, this is more reason to NOT pay taxes. They clearly aren't being used correctly.
Don't forget that Pennsylvania has one of the highest gas taxes in the USA. There was NO excuse for this bridge to go unmaintained.
SImply insane! Cars with comparable rust damage would not pass inspection in most places, yet a BRIDGE is allowed to be used with nothing done to it!
Some states still do vehicle inspections??
@@mangos2888 seems like most of them are getting rid of inspections. West Virginia is now every two years, but there is a bill to stop them altogether. Kinda amazing.
Pennsylvania. Once a year.
Hey...they did stuff! They added some steel cross cables. /s
New York, once a year.
So they knew for more than 10 years that something like this was going to happen, but no one bothered to actually fix it.
The law required the bridge to be inspected, but doesn’t specify who needs to do or pay for any fixes found by said inspections. After all, why would anyone not want to fix the expensive holes in the bridge before it collapses?
@@sonorioftrill"..why would anyone not want to fix..."
When it would require increase in funding for maintenance but the only thing on the agenda list is "cut more funding"....
@@alaric_ We had plenty of money for maintance from PA's gas tax, but the grey costume wearing welfare queens of the Pennsylvania State Police pilfered the funds to pay for their pensions.
Budget and bureaucracy?
Maybe when the bridge was built, their Public Works department forgot to add "clean drains on new bridge" to their maintenance schedule?
Drains are not that hard to clean. What a stupid, stupid cause for a structural failure.
Pittsburgh Public Works for ya
Gotta have bike lanes and "traffic calming" speed bumps.
@@spaceflight1019What do those have to do with cleaning drains?
@@moi01887 I'll make it simple: the engineers have one set of priorities; the politicians have another set of priorities. Savvy?
@@spaceflight1019 It seems like you’re implying that traffic calming and bike lanes are the cause of this collapse because they siphon funds away from maintenance. While it’s true that resources are finite, safe pedestrian, multi-modal infrastructure, and maintenance are not mutually exclusive. We can and should expect our government and transportation officials to provide both.
*edit for clarity
The protective iron oxide "patina" that is supposed to form on the surface of Corten or ACR steel does not form in the presence of chlorides. Viz.: snow melting salts. This is stated in the manufacturer's literature. I have observed that the traffic facing sides of ACR girders can exhibit advanced corrosion while the opposite side is OK. The passing vehicles spray the salt upwards and forwards and it hits the web. The material works fine if you paint it, and its need for recoating is much less than for ordinary steel.
Oh, chlorides, now I understand. In a related application I was wondering why SpaceX didn't use this alloy for the Starship launch tower "Mechazilla," but so close to the ocean it gets salt spray all the time, loaded with chlorides of course.
Interesting that the NTSB report didn't address that given the location climate.
Exactly! This was a poor material choice for a snow belt bridge expected to be subjected to large amounts of deicing road salts and chemicals.
@@andrewtaylor940no it's poor material choice for road surface treatment. When are people going to learn? Sand works just fine. Stop fighting the weather and learn to deal with it like we do up in the north. Southerners get a wee bit of snow and think they've got to melt it all before rush hour. Try doing that when it's -30 for a week straight.
@ihdieselman What? Pennsylvania isn't in the South. Most of their annual highway budget is snow snd ice removal.
Fixing old bridges won't get you reelected, until they collapse.
Then you can "fight" to get all of the bridges fixed (until people forget and you can get reelected without making it happen.)
And closing dangerous bridges will get you voted out really quickly!
Au contraire!
*If you show the Voters the pictures of the holes, it damn sight will get you re-elected!* *LoL*
@@robertbackhaus8911 *So the War was Lost, for one maitenance worker, cleaning the drains monthly!?*
@@mderline4412War? RLY?
It's not the job of a politician to do good work in office. It's the job of a politician to get re-elected. These two objectives often collide.
And the fact that there are many more structures out there in the same condition with no attention being paid to their high probability of failure is another example of criminal neglect.
Over 7% of the bridges in the US are listed as structurally deficient, or simply in "poor" condition. And this number keeps growing every year. 42% of all bridges are over 50 years old in the US. We had huge building booms in the 60's and 70's, but we don't have the money to keep everything fixed up. More collapses like this WILL occur in the future.
@@paca_bill4863We don't have enough money to do the upkeep because we give the money away.
@@kevinmiller5467 To whom you give wich money away?
@@paca_bill4863 The Infrastructure Investment and Jobs Act of 2021 invested $40 Billion towards bridges alone to repair some of the worst cases. Look at your local governments to see how these are being spent if you are not seeing things happening around you.
@@Stefan_Dahn Deffense contractors and companies as such... You like to spend trillions bombing people around the world but don't have money to have social health care or basic infrastructure maintenance... but you have freedom! lol
No one documents the neglect and disintegration of American systems like the NTSB
U and I love it
Doesn't matter does it? Still no one gets fired or put in prison.
@@silverstake88It does matter. The work the NTSB does saves lives. Look at... well nearly every episode of Mayday/Air Disasters. The NTSB isnt a law enforcement or punishment agency. Those things need to be done by the Justice System, that usually falls flat.
@@silverstake88 And we get to pay, *Now and Later!....*
You should watch the USCSB. Which is a similar US government agency that describes accidents in private chemical plants..they are amazing quality videos.
Babe wake up a new NTSB animation has been released
What is the point of yearly inspections if no action results from them?
Mostly providing evidence for future NTSB reports.
More seriously the inspection is to generate a list of recommended actions. The lack of action was likely because funding for the action was either never granted by the relevant government or never requested by the relevant authority’s management because they knew it would not be granted. This is in large part because states, cities and counties do not have the money to actually maintain all the infrastructure they own, because the cost of maintaining infrastructure in low density areas is not covered by the comparatively low tax base in the areas the infrastructure serves. Governments must then use taxes from high tax base areas to cover the gaps, which means projects in high tax base areas also go unfunded, and eventually everything gets worse everywhere.
The ultimate root cause is that low density (low tax high infrastructure cost) areas produce enough tax to build their infrastructure in a green field, but do not produce enough tax to maintain and replace that infrastructure in the long term, and were built out disproportionately starting 70 years ago - and we are seeing the effects now that the infrastructure built at that time all reaches the end of its 50-70 year design life.
@@EyeMWing "This is in large part because states, cities and counties do not have the money to actually maintain all the infrastructure they own, because the cost of maintaining infrastructure in low density areas is not covered by the comparatively low tax base in the areas the infrastructure serves."
That excuse doesn't play in this case. In PA all bridge infrastructure is paid for by the State (and sometimes the Feds) just for that reason.
@@stargazer7644 Yes: it is easy to get grants to build a new bridge. But then the municipality is expected to maintain it.
@@stargazer7644this is in the middle of the second largest city in Pennsylvania. They’re just rubbish at holding to a budget, and properly allotting resources to the existing infrastructure.
No point in inspecting if nothing is going to be done about it.
At least they have a record of the tinworm progress.
Cincinnati Brent Spence bridge has been wallowing... amazing it hasn't collapsed yet
What an utterly moronic statement. 🤣🤣🤣
I have faith there were internal-whistleblowers who did their part in communicate it to the people who need to know. Those people, who need to know, should be held accountable. Not everyone is built to be a whistleblower and go public and put themselves out there.
What's funny is the state imposed a weight limit of 26 tons for the bridge. The city of Pittsburgh, the owner of the bridge was sending their 30-40 ton articulated busses over it. Had the weight limit been observed and complied by the city, the bridge may have not collapsed for another 50 years. Pittsburgh city leaders are to blame for the collapse.
There's no mystery really. Bridge should have been condemned.
It should have been properly maintained and repaired.
@@UncleKennysPlace Would have been nice too. But a licensed PE should have condemned it upon seeing the reports. It went on way too long.
WHO at the Pennsylvania Department of Transportation is being charged with criminal negligence? It took me a minute to realize the green paint at 5:02 was a hole through the beam and I was seeing tree leaves through. Utterly amazing and not in a good way. Well done NTSB as usual. Apparently the only Government agency that actually does its job.
This bridge was the responsibility of the City of Pittsburgh, not the state (not Penn Dot). The city has a very poor record of road maintenance.
@@bknesbitt2155 To many years of one party in control. PennDot told them it was bad years ago, but mayor wanted bikeways not bridge repairs.
The Chemical Safety Board does a darn good job, too. Sadly, they have no teeth and can't get much done besides to investigate and write reports.
I live near the bridge and hike the trail under it, and I remember looking at those four rusting feet, thinking that can't be good. I drove on that bridge all the time! Yeesh!
Remember the Liberty Bridge fiasco? The bridge caught on fire *while they were repairing it.* @@bknesbitt2155
So the only real surprise here is that it didn't collapse sooner. I hope the NTSB is diving deeper to understand why the bridge was allowed to reach this condition without being closed.
Nah. That’s the justice systems job. And that’s pretty much toothless go figure.
The NTSB are great at identifying the immediate causes of accidents and producing videos / press conferences but they do seem to miss the Safety Management side of safety.
I think when he says that repairs were never completed, he actually means repairs were never started.
NTSB does great work. Thanks guys
2 years later
@@ChrisLoew You assume everyone involved cooperated.
@@ChrisLoew You can't do good work like this overnight dude
This is ridiculous... Thin metal, holes, and constant erosion; but traffic was still allowed to cross?
Hey! They added steel cables. They just needed to add a bit of duct tape, and it would have been fine!
@@AlexBesogonov Exactly!, duck tape covering that big hole 5:00 would have save it for sure
Duck tape may has stoped the rusting, should covered the steal in duck tape every year to keep the metal dry and it probably would still be here. :)
Not just traffic... massive articulated busses and trucks too.
The NTSB needs to hire the CSB animation team 😂.
Yeah, but then we might have to wait *even longer* between CSB videos.
Hello, fellow ChemHead!
They'll up their presentations eventually. Nevertheless, the crude animations served their purpose here.
The transverse tie plates as installed created ledges that would capture debris and puddle water. If this was a ship, it would have limber holes to permit water at least to pass through and reach the ground. It's as if no thought was given to environmental factors in the design. An open lattice-work would have been superior (think Eiffel Tower ).
Better than drain holes would be to have the tie plates angled steeply enough to let them drain themselves even in the corners. They might need to be thicker due to the angle, but much more durable.
@r0cketplumber In an area with frequent snow and winter weather necessitating the application of road salt, this was just a poor design. The drains should have led somewhere that took the water away from the bridge without running onto, or splashing the exposed steel structure.
@@pulaski1 I agree completely, self-bailing scuppers on the deck and self-bailing structures that inherently cannot accumulate debris are the only responsible way to design bridges in any climate, but failing to do so in a snow & road salt environment is the next best thing to criminal.
The engineers that designed and approved this design are culpable. I wonder how many of Pittsburgh's 297 public vehicular bridges have similar design problems.
@@Paul-vh6ul To be fair, this approach of no maintenance and no cleaning of the drains ever would have doomed any steel framed bridge in the region. The Liberty and sixth street bridges were in such bad shape before they we're rehabbed that they we're actually in danger of collapse at one point.
Maybe inspection images should be posted at both approaches to every bridge for review by everyone who is about to cross it. If I had seen those images from 2013, I would have found an alternate path from that moment on!
Post the inspection images, a QR code for the report, .... And the names, addresses, and pictures of the city engineers responsible for the bridge maintenance.
Lol. You say that, but in Pittsburgh, you often don't have those choices. You're not going anywhere unless you're crossing a dilapidated bridge.
Sounds like folks in Pittsburgh need to rattle some cages. If I knew that the bridge I crossed was a death trap, I'd find a new crossing.@@JeremiahLOsborne
@@hotflashfoto The problem with Pittsburgh is that you can't go anywhere without having to cross a bridge. I believe there are over a 100 bridges in this city, and all of them are in one way or another structurally deficient. I think that's what the most recent reports say. That's why I try to stay out of the city as much as possible. They have tried to shove as much stuff they can into some of the most difficult terrain.
@@JeremiahLOsborneI think the only reason downtown is flat is because of TNT. It's at the confluence of multiple creeks and rivers including the headwaters of the Ohio River.
This is the first NTSB video RUclips recommended. Feels a lot like the CSB safety videos. That is to say, it's a very informative and educational video produced by knowledgeable experts with first hand experience investigating an incident. Very good to see another federal agency do this type of public outreach!
Thanks - I always wondered why a bridge in a populated area like Pittsburgh could "suddenly" collapse; this was a very useful summary of NTSB's findings.
Just think this is The STEEL CITY,
but also part of the rust belt
they sold all the steelmaking jobs to china around the turn of the century.
was steel city. now it rusts
where'd my reply go
40 years ago it was. Now it’s the hospital/university city….
Why in earth wasn't this bridge immediately closed after the 2021 inspection? That hole is half the width of the leg.
Lawyers in Pittsburgh and other cities should do their own photographic surveys of bridges to document these issues in advance of failures. That would make settlements with relevant authorities faster and perhaps larger. The knowledge that this was happening might induce the same authorities to actually repair the bridges.
Why don’t you let the class know which one will fail next so we can send those lawyers out for the pictures!
Just make the official survey photos public.
@@jacksonbennett6151 Because then the government might fix the bridges, robbing the lawyers of their chance at a windfall.
The problem with this is it is still the tax payer who pays. You need laws on the books that require criminal neglect charges against politicians who are responsible for their respective regions. And yes I'm going right to the top.
Pittsburgh was actually hoping that the two year statute of limitations for filing lawsuits would be allowed to expire before the report was made public.
years ago i had a truck route around pittsburgh.many of the bridges i drove over you could see the exposed rebar sticking out of the concrete that had been eaten & flaked away from the years of excessive road salt in the winter.i mean it was clear as day from the drivers seat at 50 mph.i wasnt surprised at all when this bridge collapsed.
Shoutou-t to the NTSB. This was an excellent analysis and clear communication.
This is definitely a quality improvement over past reports too! Much closer to the CSB reports.
@@krissp8712But without all the goofy unnecessary cgi the CSB videos have. :)
It almost seems like the plan was to document the dangerous decaying structural elements but otherwise just do nothing until the bridge collapsed.
What good is inspection if no action is taken?
4:24 repeated inspection reports of clogged drains but no action 5:09 thinning, holes in stiffeners. 2009 cables were intended to be temporary measure
Similar to the FIU pedestrian bridge failure and the I-35w bridge collapse. In each case there were trained engineers looking directly at a serious structural flaw yet did not call for immediate remediation or closure of the structure.
Yes and that bridge was being built when it collapsed no excuse for sloppy constuction/maintanance well except money/politics. Take your pick.
*Seeing the photographs of the rust damage- especially where the iron moths had eaten the metal away!- I simply cannot comprehend how anybody could certify this bridge as safe and sound and keep it in use?!*
Amazing work. I live in PGH and we rely on bridges to get *everywhere*. It certainly makes me concerned for my safety, imagining the effort necessary to support all these massive (and sometimes ancient) bridges. Somehow I'd never seen the bus footage... Absolutely wild.
Ahh yes, lest we forget when Joseph B Fay attempted to burn the Liberty Bridge down. Would have been nice for them to have to buy a new one. I’m always suspicious of the Pitt and Duke bridges, and how many other bridges, just in the city alone, never mind the county, are derated to an effectively useless capacity to avoid actually fixing? The old Greenfield Bridge, the one by the north shore to Bellevue, the bridge by Gus’s over the tracks to the science centre. Bridges being built under other bridges to keep debris in place.
Maybe I should look a bit closer at those yellow bridges next time I am there for Anthrocon. (Had a great time last year, yall were good to us goobers)
@@katarjin Thankfully I think the ones downtown are used often enough, as well as being considered iconic enough to get maintained pretty well. Usually one of the 3 (Clemente/Carson/Warhol) by the convention center has been down for extensive maintenance for years now... Not sure if it's a continuous project or what.
And as for "you goobers" - I'm sure we passed each other in the convention hall at some point ;) I'll see ya there
This won't change until people are held accountable and thrown in jail
Typical ameritard.... Why is incarceration your ONLY tool? Ever wonder why your ONLY tool is completely ineffective?
So how many more bridges are just like this one?
Alot
Those K-frame bridges were very popular around maybe 1970. There are plenty of other examples around the Pittsburgh area. I can think of examples on the interstate down in Maryland.
The NTSB does some of the best work out of any government agency. If the others did their jobs half as thorough as the NTSB we wouldn’t need the NTSB. Of course hindsight is 20/20 but the details in these reports is astounding.
And the NTSB has a fairly small budget, and a skeleton crew, as far as federal acronyms go.
Scare part is this isn't after damage clean up pointing fingers,,, there's a hole in the support gussets (?) in a 2013 inspection, and a 2021 inspection almost half the connecting part is gone... and someone gave that the OK to keep going? Does the inspector just give a report and it's up to someone else to decide if it's ok to be on?
Yes. That is exactly how it works. I highly doubt that the inspector has the authority to shut down the bridge, but the city sure does. And they failed. Big time.
Yeah, if I had done the inspection and then heard that the bridge was still open, I would have sent a copy of my report to multiple news agencies. Of course, after that, I would have to make sure that I never lingered in a hotel carpark...
I like how that much corrosion is deemed "safe enough" for a bridge by PennDot, but if PennDot sees a speck of rust on your car it fails inspection.
I was thinking the same thing.
I had to deal with EXACTLY this!
Small hole through the exterior rockerpanel (not load bearing)... immediately failed.
Plugged it with foam and bondo... "You're safe for the roads now! 🤪👍"
How did the bridge pass an inspection 20 years ago, never mind in 2021 ?
Meanwhile PA will fail your car inspection if they find so much as a dime-sized spot of rust on the EXTERIOR panel (not load bearing) of your car!
...but this is fine for a bridge.
This looks like something out of Fallout 4. I half expected to see feral ghouls come charging out of the bus.
More like Fallout 3: The Pitt DLC. :)
Nah, that's Greyhound.
Welcome to Pittsburgh.
I was in Pittsburgh from 1970 to 1974 (at CMU) and again in 1982. I was not surprised when this event happened in 2022.
Pittsburgh and Pennsylvania government have never met the higher standards of MD (where I grew up) and MA (where I've lived since 1974).
This is an infrastructure failure caused by chronically under-funded and over-criticized government resources. Taxpayers yell and scream loudly whenever they are asked to pay the price of civilization (taxes), and then yell and scream loudly again when the things they take for granted fall down from lack of funding.
The generations of voters and taxpayers since the Reagan era (that's when this all began) have squandered the inheritance we received from earlier generations.
Main gripe is misallocation of resources. If there was more accountability for the funds we pay, and the precise items we receive for those funds, there would be less pushback. There are fairly vague budget lines, but exactly what has PPW been doing if not clearing those drains monthly as required? What has Infrastructure been doing all day if not inspecting the stalactites on the bridge pillars?
@@jaysmith1408 Here in Massachusetts, we have a town meeting form of government. The mythology about town meeting is that it provides the transparency and accountability that you seek. The reality is that doing anything with the resulting data is itself a fulltime job, and nearly always reveals the same things -- underfunded agencies do the best they can to allocate their limited resources to the most pressing needs.
Most times we're talking about triage. There are a host of projects where spending money won't make a bit of difference because the problem is too big to solve. Some projects don't make a difference because the impact of not doing the work is minimal. Most cities and towns attempt to spend each dollar where it will gain the maximum return.
I suspect that over the past five decades, there have been a long list of issues with more immediate consequences than cleaning storm drains. As an engineer, the decision to place those storm drains directly over steel legs that rust and rot strikes me as a marjor design error.
Yet if the DOT did not dump vast amounts of road salt, you would not have had this problem. I have designed a machine that will clear such roadways in one pass and leave behind a nice dry surface, no salt; no interest anywhere.
@@jvaneck8991Only works if it stops snowing after that machine passes. And in Pennsylvania, it doesn’t stop doing so for weeks. 😂 Plus, *you* tell the salt miners and mines, as a politician, that you are going to be buying less of their product, and tell me how many of them vote for you.
@@thomasstambaugh5181 OK, I see now where the placement of those drains can be a design error. You will assume that the customer, in the long term, will not perform necessary maintenance. Sounds like a good bet, sad to say.
I'm currently driving a loaner car from the dealer who is taking their sweet time dealing with the most recent string of repairs needed for an aging vehicle that should not be having these kinds of issues, but apparently the manufacturer made some design errors -- "Let's make the head gasket from metal-- should work great!" -- leading to that model year having serious issues. 87,000 miles on a car model reputed to run great at 200,000 miles. But about the loaner car-- its backup camera is located directly under the rear window washer. I can't wash the window, then back out of my driveway with a clear view from the camera. It's also vulnerable to rain, overnight dew, etc. THAT is a design error!
Pitt has a ton of bridges just like this, that countless people drive over and under, often many times a day.
Drove over this one on a regular basis for years. A bus and a few cars is the lightest load it could have expected - the intersection immediately to the east often backs traffic up onto the bridge; no telling what the injuries and fatalities might have been if it had collapsed during rush hour.
3:56 Holy crap, that driver has to have nightmares about this.
Finally we get to see the video from that bus!
I'm not a bridge engineer but when you can see daylight through the metal supporting leg it's obviously 'Buggered'.
* assuming it was not designed to allow daylight through for artistic reasons.
That's the technical term...
I think that's part of the vocab portion of the PE exam for civil engineers.
@@jamesphillips2285 Kindly remind me which School of Industrial Design favours the Gaping rusty hole look?
@@fustigate314159 In my field, Electronic Engineering, we used to have several levels of Buggered.
There was Slightly Buggered then the Standard Buggered then the Buggered beyond Belief and of course the ultimate Buggered beyond all Recognition.
They decided to paint what? The holes? The completely delaminated critical cross plate?
You act as if the directive was to coat it the day before. This is not the case. Coatings are a core principle in structure maintenance.
@@ShainAndrews Not when literally half the structure is already gone! No sane contractor would stand under that when you are striping it back!
@@benlewis4241 You are wicked slow on the information uptake.
Why was no action taken in response to multiple inspection reports? Was the cable tie arrangement regarded as an "action" that "fixed" the problem, so no other fixes were considered? What other structures in the area are managed by the same office?
Incredible that a modern era concrete and steel bridge could deteriorate that much.
Bridge construction inspector here:
I thought i had seen some bad bridges before but those pictures of the 2021 inspection would of sent me running lol
So, as I understand your description; if the drains had been properly maintained, the bridge would not have the rust/corrosion that ultimately led to it's failure.
The Charles Anderson Memorial bridge in Pittsburgh PA is in the exact same or worse condition. Weeks after Fern Hollow closed they did an emergency inspection of Charles Anderson and closed it immediately. It's been closed now for 2 years and no work has taken place.
Hey, but they did something about it! People will be safe now... except for the other bridges...
Good god. I wouldn't have even wanted to get near that thing to inspect it. That's terrible!
As too often happens, the question arises : what is a lot of inspection for if no maintenance follows ?
One would think that the countless examples of public employee incompetence would be enough to wake people up and yet public employees are invariably lionized.
The addition of the tension cables without an opposing fixed compression member added lateral stress exactly at the failure point.
This report is surprising quality!
Why am I not surprised that the cool calm collected narration didn't describe the arrest, trial and conviction of those responsible.
0:21 A hole that is so large you can almost put your hand through. How could anyone think that this is still safe? Also on the other pictures this bridge was rusting away.
Crazy to see something like this also in Germany there are many old bridges but something like this would be closed down immediately.
None of these near collapse structures have been replaced in the last 3 years, nothing has been built or replaced, nothing is back to the way it should be and nothing is better, the last 3 years have been a massive failure in every facet.
That tie plate corrosion is inexcusable, especially in a state where they still make steel, I would have tagged that bridge right then. They are lucky no one died in the collapse....
What good are inspections if nothing is done with the results?
Very informative. Thank you.
This kind of failure will continue to happen as long as all the people responsible for these chains of events get to walk away like everything is fine. That is absolutely insane the level of corrosion and the blatant negligence required for this bridge to be left in the state that it was.
These videos are master classes in simple communication of complex problems.
can this laser analysis be used before a disaster like this occurs to see bridges that are at risk of collapse?
Those that produced this explanatory video did a great job!
What is it about the USA. Can’t believe that the bridge wasn’t closed earlier with the size of that rust out (not just rust), gaping holes). Surely someone stood there and thought ‘ummm I think we have an bridge integrity problem and other parts of the bridge are carrying the load the rusts out sections can’t’
We have no money to do the repairs. It all goes to perpetual wars in places like Ukraine, and to support illegal aliens flooding across our southern border. America is being destroyed by a well-implemented plan.
Capitalism run amok. CEOs and shareholders command maximum profits, and demand taxes to be slashed. There is no money for critical maintenance and improvement.
This happens everywhere to varying degrees - just look a the bridge that collapsed in Italy, for example.
The USA compared to who? This happens everywhere.
Since the bridge was inspected every year, could those holes develop within that time frame?
Looks like it’s NTSB VS. CSB for super awesome post accident coverage!
Concidering the damage, the lack of maintenance, and the years before it actually collapsed from it; the bridge seems to have been well constructed and designed.
Maybe they should've gone with paint rather than petina, but who knows if they'd ever bothered to repaint it regularly...
My question is, why were the drains placed in such a crucial location on the bridge?
Prob because the downpipes needed to be attached to something? Something like the legs?
Wow! I thought that picture at 4:56 was taken AFTER the collapse -- until I noticed the "2017" label at the top. How does THAT pass inspection?
3:23 video footage of bridge collapse from the "articulated bus".
That's incredible footage.
@@fitshamer The collapse chasing the bus like something out of a disaster movie...
@@spankeyfishWhat for movies, when you can experience the disaster live and in color, while going home to your family. AND the family can (should? 😬) be happy each day you make it home alive. 😂
it's like it's an actual disaster, eh, @@spankeyfish
The 35w bridge collapse video does not allow comments. The #7 pier was fixed bearing .before the collapse a stock pile was pile up around concrete columns between the top of the bluff and columns next to the river. When the bridge collapsed the stock pile of dirt and sand had been removed those columns were unstable and allowed too much movement and may have contributed to excess longitudinal movement and contributed to this disaster. After the new bridge was finished the stockpile around the new columns returned. Why was that. I lived in the Marcy Holmes neighborhood a few blocks away. That bridge was unsafe or structurally deficient for 20 years or more. MnDoT and the State Legislature made a bad decision to attempt repair rather than spend money to replace it. They ended up replacing it any way with the loss of 13 lives.
That bridge was opened in 1973 so almost 50 years. There's lots of infrastructure in America -
Perhaps active inspection/maintenance/repair programs could be done on all infrastructure items above 10 years in use - that can stimulate the economy in various ways, too.
Bridge capacity & bus weight ?????
does a 26 ton eight restriction seem pretty low too?
yo @post10 the DOT isn't cleaning their drains again.
Insane.
This is obviously not where the road taxes that are continuously collected goes.
I can’t believe there was holes in the legs for 10 years and was documented along its demise. What’s the point of doing inspections?
So who was ultimately responsible for repairs that were never done?
I'm so glad PA learned from this that no other bridge has collapsed in the state since this incident.
Give it time
yet
Thanks for the factual analysis NTSB.
All for the sake of clearing some drains.
Hopefully those who acted negligently will be prosecuted.
Making steel structures that don't shed or drain accumulating water was a major oversight. Its such a basic concept in steel structure design and could have been corrected even after the bridge was constructed with careful drilling of drainage holes.
Are there any other bridges like this one that are still being neglected?
Isn't it great to know that there are thousands of these types of bridges all over the northeastern United States, from Chicago to Boston? Great job! Stay classy! 🙄🙄
What? Is that all? What I was waiting for were recommendations of what should have been done to prevent rusting. This was similar to the collapse of the major bridge in Genoa, Italy 10 years ago. And that one had many fatalities.
Was winter snow loading included in the weight restrictions? Weight of a few inches of accumulated snow could easily exceed the posted limit.
Yes, if US engineers can count to 3. As a German seeing this, I am not sure and documents the decay of the US to a third world country.
How is it possible that the bridge wasn't closed down after the 2021 inspection??? The damage document is severe and the continued use of the bridge by the management agency is criminal!!!
I live here, and this is more info than the news gives.
That's called corten steel. Very susceptible to corrosion from various causes including exposure to road salt. There are plenty of examples of this. Crazy they kept it in service.
Yea, well, like a lot of things, it works fine if you follow the instructions. Nobody reads those.
somewhere out there a structural inspection engineer that worked on this bridge is saying "I have told you so for many years and they still did not listen.."
Absolutely incredible (practically criminal) they allowed the corrosion to get that bad. I moved to Pittsburgh 6 months ago and I gotta admit; the condition of some infrastructure around here certainly is...an experience.
That articulated bus was the straw that broke the camel's back.
Pittsburgh winters are very hard on steel. This makes me wonder what the condition of the many bridges in that area are like.
It's so interesting that the bottom flange curled inward. Was that because it came in contact with the ground as the bridge collapsed?
It could be due to transverse tie plate being in tension causing the flange curling inward when the tie was released/broken (I'm no expert, I might be wrong).
@@nilfar3652the transverse tie plate went with the shoe. It had nothing to do with the outer flange curling up after it separated. That was almost certainly due to it impacting the pylon on the ground or something else.