> The Port Authority bus was traveling eastbound at the time of collapse. The bus was equipped with seven cameras: one forward-facing camera, one right side aft facing camera, and five interior cameras. Video data from these cameras have been recovered, and the initial assessment of the video data is consistent with the initial assessment of the bridge components. The National Transportation Safety Board (NTSB) will convene a group of specialists to analyze the video for further information useful to the investigation.
I hadn't thought about bus cameras capturing the collapse -- wonder if this'll ever be released (or leaked)?
Very interested to hear the outcome of this investigation. As a Pittsburgh resident, it's pretty common knowledge that our ~450 bridges are not in great condition, and this just confirms it. The last inspection on this bridge was done in September of 2021 - Although it was determined to be in "poor" condition, it wasn't deemed unsafe. Less than 6 months later it collapses. How many more of our bridges are this close to collapse?
If I remember things correctly about 45,000 bridges across the US are in poor condition and the original Infrastructure Bill targeted 10,000 of them.
The Bill got watered down further.
There is simply too much infrastructure to maintain, and more and more stuff is being built every day with no realistic plan for long-term maintenance. It's a losing battle.
Strong Towns makes the case that there is just too much infrastructure in the US and the level of sprawl that we are built at is economically unsustainable in the long run.
Except for a very generous interpretation of "the long run", I don't buy this. We pay more than enough money in taxes to maintain our infrastructure. The problem is governments misallocating and wasting funds.
The world Strong Towns wants is emotionally unsustainable. Maybe there are people who can handle it, but I would go insane in the dense cities it suggests.
Let the people who like dense towns live there, and stop trying to tell the rest of the people how to live.
Strong Towns also tries to creates cities where no one from the outside ever comes in, since there's no way of getting there (no parking, not enough roads).
People in large cities also like to "get away" during the summer - but there will be nowhere to go in his world.
Nobody’s telling you can’t live in a rural area. Just don’t ask me to pay for a road and a water main out to reach you from the city. Get a Jeep and dig a well and move if the water dries up.
Maintaining things is not necessarily less costly or even viable, compared to building things.
Also, labor costs have gone up dramatically due to a variety of factors. Increased safety standards, less supply of labor relative to demand, increased liabilities due to tort laws, etc.
Also, borrowing from the future to build today is easy when population is exploding and you know everyone is having 3+ kids which will expand the tax base. That has not been true for quite a few decades now, with tax bases declining in many areas and political appetite for subsidizing those areas is waning, in my opinion.
Less future growth means more restrained borrowing today. There is also a significant and increasing amount of the country’s resources being spent on keeping old people alive that was not the case when all the old infrastructure was built.
I assume there have been, but based on all the reported costs of building infrastructure, I concluded that any reductions in costs must have been greatly offset by increases in costs.
This one was especially bad -- I can't find the twitter post, but someone had snapped a picture in 2018 where a structural member had rusted completely through. The bridge should have been immediately shut down but was not.
That’s the one where it was unclear whether it was a concern because there was a bunch of more recent cabling around, and the agency responded with some sort of ticket number, yeah?
One problem is steel reinforced concrete is nearly impossible to detect rusting until it makes its way to the outside of a member. The ends of the bridge were reinforced concrete, so it's possible they just couldn't detect the problem and so didn't deem it unsafe.
IIRC some one traveled under this bridge last year and took photographs of several of the metal supports which were entirely rusted through and not connected to anything.
I saw those photos as well, and the presence of steel cables with turnbuckles to reinforce the structure lead me to believe that the damage was known and someone decided that the minimal reinforcement was adequate.
I suspect that if that was the primary cause of the collapse, the NTSB would have mentioned it directly already.
Which may have been fine if other supports were taking the load. Visibly rusted parts are easy to diagnose, thus if that particular part was unsafe it would have been quickly deemed as such. It could be that it contributed to the collapse, but that it alone wasn't enough to justify it as unsafe.
The most surprising the thing from the article is the posted weight limit of 26 tons. I'm no structural engineer but that seems very low to me for the size and length of the bridge? From the looks of the picture, shouldn't that bridge support like 5x to 10x that weight? A quick google shows that the average car weight is 4156 lbs [1]. So the bridge can only support roughly 5.5 cars before its over limit? And that is not considering common heavy vehicles likes semis, buses, etc.
And with auto industry going to toward EVs, vehicles are only going to get heavier, not lighter. The upcoming Hummer EV will be 9000 lbs [2] for example. This bridge seems awfully under-spec'd for its purpose. Someone please tell me that I am interpreting this number wrong.
I don’t inherently disagree agree with you but 9k lbs isn’t too far out of the range of normal passenger vehicle weight. But I would agree that many vehicles in the US and North America are probably oversized.
An Audi A6 weights 4500 lbs, Tesla Model S LongRange is 4800 lbs, Honda CRV is 3500 lbs, Honda Odyssey Minivan is 4600 lbs, Ford Explorer is 5000 lbs, even a Ford Expedition is "only" 5600 lbs.
What passenger vehicles are in the range of 9000 lbs?
That's not really a passenger vehicle though, it's a truck (it's right there in the name "pick up truck"). Just having more seats doesn't make a truck into a "passenger vehicle", my brother used to drive a 40,000 lb heavy truck that had a crew cab that seats 6, but no one would classify that as a "passenger vehicle".
It was so heavy that when he took it home, he couldn't drive it all the way home, he had to park it a half mile away and walk because there was a bridge with a 10 ton weight limit that he couldn't cross.
Listen, I can haul sheet goods on the roof of any car all day long and he happy doing it.
But the problem is that YouPeople(TM) (as opposed to you personally) won't be happy about it. Instead of screeching about the environment you'd be screeching about safety. But it's not really about the environment or safety, it's about class. The fact of the matter is that moving any sizeable amount of goods (like some plywood for a garden shed, or a new stove, or similarly mundane things) with a car or crossover just doesn't pass for acceptable behavior for the slice of society that we're talking about here. People need more vehicle than they "need" for the same reason a 30yo finance professional "needs" a couple sets of nice clothes. It's what his peers expect from him. The quirky college professor can haul a sailboat on the roof of his prius and the tweaker won't be bothered for running scrap with a minivan but outside of that it's just not what "nice people" do (not that either of them care about the opinions of the kind of people who deride them). Meanwhile white collar people with three kids won't even shove them in a crossover once a week if they can avoid it. They'll commute in a 3-row SUV that costs twice as much to operate instead.
People buy crew cab trucks and 3-row SUVs because YouPeople(TM) expect them to "act their income" and they "need" the capability of these vehicles often enough to justify it.
> People need more vehicle than they "need" for the same reason a 30yo finance professional "needs" a couple sets of nice clothes. It's what his peers expect from him.
I'm afraid you're projecting your own issues on others...
While I didn't reply with the same degree of hostility as the GP, I had the same emotional reaction to your comment. My immediate thought was "who are you to say what I 'need'?"
I'm self-aware enough to realize that this is because of a larger cultural struggle in the US between "rural" and "urban". It's not quite that simple, but that's a close enough approximation for the conversation at hand.
The rural people on the US feel like we are constantly fighting a system in which we have no voice. We're subject to regulations that we feel to be frankly ridiculous; regulations that get in our way, make our lives more difficult and expensive, and most of all... don't even serve the purpose for which they were ostensibly designed.
In that context, the GP's response to your comment is understandable.
This is a common sentiment but it always makes me chuckle. People living in rural areas quite literally have more of a voice (as much as that counts for anything with political corruption) than people living in urban areas due to the Senate and gerrymandered congressional districts.
It was tongue in cheek/sarcasm. Point is people with the money to buy new buy more vehicle than they "need" because it is what society expects of them so in some sense they "need" it to meet the expectations of those around them.
> Point is people with the money to buy new buy more vehicle than they "need" because it is what society expects of them so in some sense they "need" it to meet the expectations of those around them.
I'm afraid that you are guilty of what psychology would call "projection". Unless you can back your views with hard facts. I have yet to meet anyone just blowing away $100k on a truck that don't NEED.
> In EU you don't see trucks or many heavy vehicles like that at all.
It’s a side-issue, but I see this type of statement all the time about “Europe” and have to say, in Sweden - and even on the suburban streets of Stockholm - these enormous American pickups and SUVs are amazingly common (although most of them don’t go over the 3500kilo limit).
They are not as common as in the US. And crucially, they are not (yet) a status symbol. Someone who can afford a vehicle like that as a daily driver (not a contractor) will get a huge-ass Merc or Audi instead.
> although most of them don’t go over the 3500kilo limit
I bet most not even go over 2000kg. My SUV is 1900kg (4k lbs) and is hybrid so has extra weight due to batteries. I think it's a very heavy car and considering downgrading again.
Please do not imply were dumb. We're not spending 100,000$ just to show off. We do need them, because we need to haul 2000-4000lb at a time over hundreds of miles and tow 5,000lb to 30,000lb on a regular basis. My biggest haul personally was about 20,000lb (of actual payload) over 500mi, and I regularly max out my 2,500lb capacity dodge 2500.
You ain't gonna move that shit with a Citroen C2.
Also, it's not just a matter of payload. The bigger wheelbase and larger tires make them much more drive able in snow or mud or ice which is common weather around. Small cars are a safety issue on black ice.
I don't think anyone has a problem with professionals using tools fit to task. (I certainly don't.) I just personally don't want to have to walk or bike on streets where trucks are moving a combined weight of 5 or 6 tons at high speeds. I think this could be solved with smarter street/highway design, which would also help drivers get from A to B more efficiently.
And FWIW, I grew up in rural Indiana (USA), soybean and corn country. It's definitely not just professionals driving these vehicles. Actually I'd say most trucks on the streets growing up were NOT used by professionals, the real farm trucks were often barely street legal and could never seem to get past 30-40 mph with a load (or without heh).
I'm not an urbanite, but on the rare occasion I need a pickup truck, I rent one. I don't like owning things I only need occasionally, I use our communities tool lending library too when I need a tool for a project.
Just as if you could plan which tool you'd need for a job... You'd be surprised how quick you can go from using a ratchet, to an impact, to an air driven 3/4" impact, to requiring an oxy-acetylene torch for a given job...
How about we agree that we just don't have the same lifestyle ?
Oh, I agree we don't have the same lifestyle, but I don't agree that everyone that "might" need a pickup (or an oxyacetylene torch) should own one because they might have a use for it 6 months from now.
I'm not sure I understand the problem -- you said you need a big truck to provide a service (haul your food, your mail, etc), which is totally fair, we all use things that were hauled around on trucks, you can't build a road by hauling in asphalt on a Prius. So if there's, say, a carbon tax on fuel, when fuel prices go up, everyone that uses fuel to provide service will see higher costs, so the providers will all increase their rates to make up for it. Many transportation providers already charge a fuel surcharge when oil prices go up.
Why would you start a civil war over it?
I'm sure that externalizing environmental costs is attractive, but that just ensures that no one is going to optimize for it.
The problem is that most farmers in the modern era are completely reliant on a combo of government subsidies and massive amounts of bank debt in order to stay afloat. It's a pretty huge problem and part of why the industry is massively consolidating. Also there are things like being required to license patented seeds, tractor/combine companies prohibiting personal repair of vehicles/equipment.. I don't think medium/small farming as we think of it will exist in a couple decades.
That's the problem, you just repeating the Gospel without understanding the externalities involved in the regulations you advocates for.
Many times, you are not free to set the price of goods, especially in today socialist / regulated economy. Your costs go up, your margins profit go down. There is so much you can squeeze. Heck, DEF sounds nice to save the environment & all, but when your combine three a DEF code and pretty much blew your engine 400 miles from the nearest dealership right during harvest before a storm, goes into limp mode and prevent you from harvesting, you're literally fucked, your all farm might even go bankrupt. Don't even count on insurance to save your ass, because you already had to cut back to focus on other coverage to mitigate skyrocketing fertilizer costs, which doesn't matter anyway because the price you'll sell your production 6 month from now has been set a thousand mile away by a white collar asshole right after his daily jerk off and line of coke. But what a beer sipping urbanite would know of actual hard constraint while at the same time, accusing us of social grand standing. Just GFY.
You pretend yourself smart, but you're not. You sound like Marie Antoinette "let them eat cake". Next thing you know, your head hang on a spike in front of an angry mob.
You seem to have strayed far from "I drive a big truck because I need to haul heavy stuff", now you've moved on to "If I can't pollute as much as I want to, I can't make a living".
A DEF code is not the only thing that can make a combine fail, and if you're one mechanical failure away from bankruptcy, it's not the DEF that's the problem.
A lot of them just use them for driving to places that they could do in a car. How many truck you see driving which are completely empty? Or how many you see who are transporting stuff that could easily have been done in a van?
That's complete bs, see my comment above. Pickups are much more flexible than vans.
The problem is the insurance model which insure the vehicle rather than the driver. Thus why some people daily drive their pickup because maintaining another beater is too much cost.
Every now and then their 5' 100lb wife will use that truck to go for groceries and then you'll see them there, because you have no life in the real world, and you'll judge them based on that single interaction alone.
Meanwhile, the next day, her hubby and the family will tow an 8000lb boat to enjoy the lake, and heck they can even stop at the hardware store pick up a couple 1000lb of concrete / 2x4 for their home improvement projects.
I've personally saved a few grands this year in various fees alone by being able to haul shit and do DIY home improvements.
But sure, that's only for social grand-standing...
In the EU you need a goods vehicle (truck) license to drive a vehicle + contents weighing more than 3,500kg (7,700lbs). Even most RVs here come well under that limit so you don't need a special license.
Yes, it is. I drive a 1988 Suburban 4x4 with a solid front axle, leaf springs, and all the old school heavier construction. With my fat lard butt in it, it's just under 6000lbs.
This video doesn’t start with “hello I am grady and this is practical engineering”, it’s unwatchable (also the sad / doomy music is distasteful, and so is claiming knowledge of causative factors when the incident is under active investigation).
> The posted weight limit on the bridge was 26 tons.
Is it just me or does this weight to length limit seem incredibly low? That articulated bus empty likely weighs 20 tons. An artic bus plus a few cars is already well over the 26 ton limit. I'm sure this bridge has also seen a fair share of truck abuse as the abysmal weight limit combined with the likelihood that truckers only see the weight limit once they're at the bridge with no way to turn around and no easy bypass route so they say screw this and drive their >26 ton rig right over it.
Complete speculation based on reading the linked report:
The bridge suffered a fatal compromise but stood with light traffic. Until some combination of speed and weight of the bus pushed it over the edge. Something happened in the minutes or hours before the collapse and it was doomed to fall.
Perhaps it had been in a slow collapse for awhile and the 'point load' of the heavy bus in that moment caught it just right. There are pictures from several years ago of major structural crossmembers completely rusted through to the point they weren't even attached;
The odd thing to me is that a bus route is regular. I would bet that a bus this size runs on that bridge fairly regularly throughout the day; a bendy-bus is never used on a route that doesn’t need it, it’s harder to drive and uses more fuel.
I could imagine that having periodically changing loads like rush hour traffic could cause a critical failure state. The slow flexing between day and night eventually causing something to deform/crack/shift to the point that the next big traffic load causes a collapse.
If prior NTSB reports are any predictor, we'll eventually learn all about the confluence of things that led to the collapse.
From the article, the posted weight limit was 26 tons. A quick google search ("bus weight") shows that buses can easily exceed that limit and the bus on the bridge was a "double" bus.
Maybe the bus wasn't supposed to cross that bridge?
I seem to remember that bridge weight limits aren’t as clear as just a number like that. I’d have to look at the DOT site, and I’m on my phone and too lazy right now. But I’d be willing to bet that a limit is per axle with other factors multiplied in for how close tandem axles are. It’s more about weight distribution than total weight. The posted signs are meant to be read by truckers who know the formulae.
How did you calculate that? I don't know how much snow there was, but 10 inches of snow has around 1 inch (2.5cm) of water.
The bridge was 136m long, by about 13m wide and assuming 2.5cm of water content:
136m * 13m * .025m = 44 m^3 of water, or 44,000 kg, roughly 50 US tons.
A newspaper report said there was a light snow with 1 or 2 inches accumulated since 2am the morning of the collapse. Photos of the scene showed grass and small rocks on the ground visible through the snow, so it doesn't seem like there was a lot of snow on the ground. Even if there was heavy snow a couple days before the collapse, most of it would have been plowed off, I don't see big berms of snow on pictures of the collapse.
So if there was just a couple inches of snow, then it was probably closer to 10 tons worth of snow.
But what if it was at that top range, 22.75 tons. The math would add up, with 5 other cars on the bridge weighing an average of 1.4 tons each, we would have 29.75 tons or so on the bridge. Before the 10 or so tons of snow is added.
Poor maintenance, bad decisions to remove part of the bridge support instead add another strip or just weld it again and ... salt in the roads that maybe end in the water or drip from the road above. Corten steel is very durable, add salt and this is a different question.
Corten steel is often used structurally, even in recent structures, because the idea is that the rust forms a protective layer. As long as water is not allowed to pool, it shouldn't rust through.
I'm familiar with the structures shown in that link. The U.S. Steel Tower seemed to be holding up well when I worked there, although looking out some windows you could see slightly worrying depressions in the steel beams where water had pooled over the years, and the steel had rusted away a bit (leading to more pooling). The Delaware footbridge was constructed much more recently and still looks new - no signs of wear that I've noticed walking across it.
If Corten steel is not durable enough for structural use, we're in trouble. It's used quite a bit, at least in the northeast.
My vague recollection from my first year engineering course, that I dropped before failing, almost 20 years ago (caveat train! Choo choo!) is a failure critical component is a component that if failing would trigger a complete structure failure.
There are parts of bridges where any failure would be expected to cause complete collapse, like the cracked beam on the Hernando de Soto bridge (happily that span turned out to not actually be critical). But as the Hernando de Soto bridge showed you can have a complete failure of a major structural element without a collapse (in this case we’re lucky that accidentally happened).
So if the report says that none of the instant fail section were responsible I’m going to trust that.
I wonder if maintenance schedule and state information should be gathered in a public database. I know US has thousands of entities of infrastructure but some manpower and some tablets is all you would need.
Money is the limiting factor. Tax dollars are already stretched thin. In many areas of the country infrastructure maintenance is at unsustainable levels with no easy solution.
Except the stone in this case is absolutely dripping with blood being slurped up by fat scavengers and building aircraft carriers (because we NEED 12 of them of course) while some asshole wags their finger at us and tells us this pinch of sand is all we can afford.
I take your point in good spirit, but there may be an argument to be made that military power is a net asset. But it's beside the point of my original comment. Local infrastructure budgets are not equipped to keep up with the demands.
A "fracture critical" component is by definition a component that will cause a structure to collapse should it fail :D
We know what that "fracture critical" components of a structure through analysis of the design. So what the NTSB is saying here is that none of the components of this bridge that were identified as being fracture critical are the cause of failure.
Of course that doesn't mean there wasn't a single component failure, it is possible that there was an error in the analysis and a fracture critical component was not identified. Alternatively an error in construction could result in weaknesses in the structure leading to more fracture critical components.
It's also possible there were existing failures in non-fracture critical components that had not been detected, in which case you are getting closer and closer to every component being critical.
I hadn't thought about bus cameras capturing the collapse -- wonder if this'll ever be released (or leaked)?