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Fern Hollow Bridge should have been closed years before it collapsed

practical.engineering

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Re: Fern Hollow Bridge should have been closed years before it collapsed

#161

Post by quesera »

kube-system wrote: post #97
pintxo wrote: post #41

Earlier quoted context omitted.

Someone else posted the NTSB video on the bridge: https://www.youtube.com/watch?v=J-VnWB4fiFk I am fairly certain that a large majority of people, if they'd have had access to those images of the bridges structural members, would have stopped using it.

Most people are unable to accurately diagnose a bridge structure other than "yeah looks rusty". And if that were the case, they wouldn't be driving much of anywhere in that part of the country, which is called the "rust belt" for a reason. Pittsburgh has a very high number of bridges, if you go anywhere in that city and you don't want to cross a rusty bridge, you can't go very far.

> which is called the "rust belt" for a reason

...but not for the reason you're implying.

The "rust belt" used to be the "steel belt", until free trade agreements made the US steel industry non-viable.

Rust is symbolic of that decay.

All of the infrastructure that was built when these areas were economically solid, is now rotting along with the economy that built them.

Re: Fern Hollow Bridge should have been closed years before it collapsed

#162

Post by quesera »

EricE wrote: post #102
beAbU wrote: post #20

Earlier quoted context omitted.

Yeah it's exactly this mentality that resulted in the Ford Pinto scandal of the 70s. How does that 1:4M probability change when you commute over the bridge twice a day? Humans are notorious for being bad gauging risk, and we very often make the mistake that past success means lower risk of future failure, which for a deteriorating bridge is exactly the opposite of what's going to happen. In my opinion bridges shouldn…

The Pinto thing was dramatically overblown. And seriously set back the acceptance of small cars in the US. For a supposed environmentalist and consumer advocate, Ralph Nadar did FAR more harm than good by grifting off a bunch of sensationalist poppycock. That he's still looked upon as some sort of folk hero is beyond disgusting and just shows how gullible people continue to be paying attention only to the sensational…

Ralph Nader's direct harm to the US continued into at least the year 2000, the legacy of which is even more pronounced today. :(

Re: Fern Hollow Bridge should have been closed years before it collapsed

#163

Post by nemacol »

hi-v-rocknroll wrote: post #33

For context, there were 42,391 structurally deficient bridges in 2023.[0] 16 of the worst are in LA county and several see 300k trips daily, including one carrying the 405.[1] 0. PDF https://artbabridgereport.org/reports/2023-ARTBA-Bridge-Repo... 1. https://artbabridgereport.org/state/ranking/top-bridges EDIT: States with the least % of SD bridges: AZ, NV, TX, DE, and UT. WV and IA have the most at almost 20% SD brid…

Awesome to see WV at the top of yet another list of shame.

While our state representatives are issuing a tax refund because we are "running a surplus"

This state is wild. I bet it will be the first to be merged with a nearby state because of poor governance.

Re: Fern Hollow Bridge should have been closed years before it collapsed

#164

Post by vuln »

jldugger wrote: post #159
jon_richards wrote: post #149

Earlier quoted context omitted.

Texas averages 36 inches of rain and 2 inches of snow each year. Ohio gets 40 inches of rain and 28 inches of snow.

> Texas averages ... 2 inches of snow each year. Really? That does not comport with my experience growing up there.

Climate trends change over the years. How long ago did you grow up there?

Re: Fern Hollow Bridge should have been closed years before it collapsed

#165

Post by throwaway211 »

buildbot wrote: post #132
throwaway211 wrote: post #91

Earlier quoted context omitted.

Trains cross bridges easily as they're either balanced with each half on each side, or half on and half on ground. And other time's just between these stable points. Furthermore, trains run on tracks which reduces chance of turning acceleration.

Unless it’s a floating bridge…

The thing about floating bridges is they don't need to span a waterway. The just need to link the part where getting onto the bridge then the bridge itself move to the exit section.

Floating bridges also don't necessarily need to have fixed points to load and unload. With suitable stabilisation and propulsion, they should be able to move to any number of loading and unloading points. We could have a floating bridge per train, vehicle, or any unit or set of users.

Re: Fern Hollow Bridge should have been closed years before it collapsed

#166

Post by bobthepanda »

buildbot wrote: post #132
throwaway211 wrote: post #91

Earlier quoted context omitted.

Trains cross bridges easily as they're either balanced with each half on each side, or half on and half on ground. And other time's just between these stable points. Furthermore, trains run on tracks which reduces chance of turning acceleration.

Unless it’s a floating bridge…

there will be a rail link across a floating bridge in seattle opening in 2025.

it was supposed to open earlier, but the contractor messed up the concrete pour and is fixing it at their own cost. but that doesn't have much to do with the fundamentals of the floating bridge itself.

Re: Fern Hollow Bridge should have been closed years before it collapsed

#167

Post by jameshart »

quesera wrote: post #160
jameshart wrote: post #93

Earlier quoted context omitted.

> Let's say it would collapse with 100% certainty randomly in the next three years, and you're in the danger area for 2 minutes, with a 20% chance of fatality Or how about let's say it would collapse with 100% certainty randomly in the next three years, and a school bus with twenty kids in it drives over the bridge twice a day, with each child facing a 20% chance of fatality. ‘I probably won’t be the one who dies whe…

School buses are never a useful way to think about risk. You might not be intending it, but this is a cheap manipulation technique. Bridges sometimes fail catastrophically, with risk to life. Modeling risk is a necessary way to consider the costs of mitigation. Leaving aside the poor helpless babies, what metric would you suggest?

School buses are an excellent way to think about risk if you are a school transportation planner. I was trying to give you an example of someone who might make a different risk calculation than an individual.

Re: Fern Hollow Bridge should have been closed years before it collapsed

#168

Post by rcxdude »

michaelt wrote: post #154
rcxdude wrote: post #143

Earlier quoted context omitted.

That's one of the points in the video: the paperwork tends to obscure the state of the system to decision makers. It's easy for the bridge inspectors (or even a random member of the public) to see that it needs to be closed down and repaired, but it's not what the decision-makers see: they see a 100-page report with a long list of action items, many of which are not actually incredibly urgent, much like every other b…

That's related, but it's not my point. Saying "decision-makers miss details in 100-page reports" makes it sound like the report is merely too thorough , and the inspectors did too good a job . My point is the report's summary could have said "This bridge will fall down within 3 years" instead of obscuring the with vague, watered-down jargon like "structurally deficient"

The problem is the inspectors aren't even in a position to make a judgement call like that: they're given 100 pages of boxes to fill in and they have to color inside those lines. It's a systemic issue of how the jobs are split up and the communication works between them. (see the fact that the reviews did indeed trigger some work to be done that would actually make that judgement call... by an engineering firm that never actually saw the bridge and in part for that reason screwed up the call).

Re: Fern Hollow Bridge should have been closed years before it collapsed

#169

Post by gottorf »

erikaww wrote: post #151
eauxnguyen wrote: post #126

Earlier quoted context omitted.

There's a road near me that's been replaced by a large 4 lane state route. There's almost no reason to drive it as there are no houses or farm access. The bridge is being completely replaced. The road is closed during construction, and I think the only people impacted by it are the recreational bikers. A boondoggle while other bridges around the country are in dangerous disrepair. I wish we knew there was a sensible…

Yes! I want a cost benefit analysis and to ask every stakeholder imaginable for any sort of road repair or expansion. The fact that not every repair or expansion has a single improvement for non car users is pitiful. We need to hold road infrastructure to the same consideration as we do transit and rail. If we didn’t give it unlimited funding, then it would already be doing this. We are wasting trillions and losing s…

> Imagine if this money was put into education or healthcare or transit. We’d actually have a net benefit!

Based on the evidence, it's hard to imagine that lack of money is the problem with those three things.

K-12 education in particular has seen more and more money spent over the decades while the number of students, teachers, and student outcomes have stayed more or less constant (the extra money mostly goes to administrators to administrate the extra money). Higher ed has gotten famously more expensive while delivering a poorer product, with grade inflation and recently a focus on worthless social activism diluting what it means to have a college degree at all.

On healthcare, the US already spends close to one-fifth of its GDP on it. Its per capita spend is over 50% higher than the next-highest country, Switzerland. And what do we have to show for this, other than an obesity rate exceeding one-third the population and diminishing life expectancies? I don't know how more money could possibly help this situation.

Transit only makes sense in a few cities (largely due to idiotic zoning that prevents the kind of densities that would enable transit) and even then, if you look at things like NYC's East Side Access project, it would be hard-pressed for a public works project to spend taxpayer money less efficiently. And to truly improve the transit experience would require a concomitant improvement in the social fabric, which is its own set of problems.

Re: Fern Hollow Bridge should have been closed years before it collapsed

#170

Post by gottorf »

jldugger wrote: post #159
jon_richards wrote: post #149

Earlier quoted context omitted.

Texas averages 36 inches of rain and 2 inches of snow each year. Ohio gets 40 inches of rain and 28 inches of snow.

> Texas averages ... 2 inches of snow each year. Really? That does not comport with my experience growing up there.

"Averages" is doing heavy lifting in GP's statement. It's a vast state, after all, and how meaningful is an average between the climates of Houston and El Paso?
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