The ironic part is "The bridge replaced a steel truss bridge built in 1895 at the same location". Engineers in 1895 knew how to use steel trusses and built a bridge that lasted 100+ years, and in 2012 they decided to use glued wooden beams and it fell apart in 10 years.
Well perhaps Plan Arkitekter and Norconsult can take a trip to the archives and see what the engineers in 1895 knew before building any more structures.
> Engineers in 1895 knew how to use steel trusses and built a bridge that lasted 100+ years
It's a little too strong of a claim. Plenty of poorly designed steel bridges from the 19th century have collapsed as well, despite the superior material.
> Plenty of poorly designed steel bridges from the 19th century have collapsed as well
That's true. But I only meant that particular bridge, which did last for 100+ years. So, when the architects and the engineers go to the archives to relearn a few things, they can focus on the ones which haven't collapsed.
To be fair, there have been a lot of advancements in timber and glue -- They just didn't take into account their weaknesses when designing (e.g. Stress that would pull laminated beams apart).
I believe the failure happened in the joint between the wood and steel. The joint was a sandwich with very thin slices and with many nails. Anyone with materials intuition knows that puncturing a material to such a degree weakens it. Mix in constant moisture and single points of failure..
Should have been a couple of big old bolts and some bracings, alternately thicker slices in the sandwich
Isn't that basically arguing "Don't talk to me about statistics, I want to talk about this one specific data point"?
Bridges on the whole are pretty clearly better built and safer today then they were 130 years ago. I don't think there's any significant argument to the contrary. There are outliers in both directions, obviously. The old one at this site looks like it was pretty great. The new one sucked. That doesn't say much about why that was true, just that it was.
> On the whole they may be better built, but the same design in steel would likely not have failed?
I don't see how that follows? Lots of steel bridges have failed over the past 130 years. The overwhelming majority of new-built bridges or any material don't fail.
People really, really want this to be about "aesthetics" because it confirms their priors about being smarter than the rest of the world or whatever. I'm just saying that's 100% bunk and that there's zero evidence for that hypothesis.
Architecture has had a "strong focus on aesthetics" since the very first stones were piled up to make a temple. Let's not get ahead of ourselves here.
> Isn't that basically arguing "Don't talk to me about statistics, I want to talk about this one specific data point"?
And why not? In this particular case, the statistics did not justify the expectation that this bridge would be at least as robust as the one it replaced.
There's a general point to be made about engineering progress, but here we have a case which bucks the trend. Speaking in generalities when the topic is a specific incident is a way of missing the point.
Corrosion weakens the steel. It's literally the metal flaking away.
All steel corrodes. Even stainless.
Once corrosion sets in and the outside of the metal starts to pit, the corrosion speeds up drastically. (The old area vs volume thing, same thing that makes lump coal difficult to ignite while aerosolized coal dust is practically an explosive).
Here's a modern US bridge - all steel - that collapsed in Pittsburgh two years ago. In some areas over 80% of the original steel thinkness was gone after 49 years.
The purpose of the hull is to protect the paint.
The purpose of the reactor is to drive the paint around.
The purpose of the SUBSAFE program is to ensure the paint comes to the surface and will not be lost.
The purpose of the cathodic protection system is to back up the paint.
The purpose of the weapons is to defend the paint.
The purpose of the Special Hull Treatment is to protect the paint.
The purpose of the Vertical Launch System is to destroy those who would do the paint harm.
From reading the linked article it seems that they are continuously painting but it’s not really end-to-end then restart. It’s more of an ongoing maintenance as-needed, at least based on the description on that website.
Now that effectively might mean then combing over the bridge end-to-end and painting as needed so what I said might be a distinction without a difference.
There so far haven't been any steel bridges that have actually lasted centuries, even if we highly suspect that they are capable of it with the right maintenance.
ETA: Also, the ones that have survived aren't road bridges. They're either railway bridges (and thus were built strong in the first place) or have been relegated to historic preservation/pedestrian use only. Modern cars and (especially commercial) trucks are far heavier than early vehicles. A road bridge built in the 1850s was only designed to carry foot traffic and horsedrawn vehicles.
Something like 20% of the bridges in this country are 10 years or more past their design lifetime and mostly not due to be replaced any time soon. You think they're keeping on top of painting every one? Saying preventing corrosion is as easy as slapping on paint is like saying computer security is as easy as not leaking your password. There are a million things that could happen, many of which are outside what any single person could control.
I don't know in what poor country you live, but in my country bridges are well maintained and I don't recall a single critical failure. Even though we're one of the poorest EU countries.
"There are more than 617,000 bridges across the United States. Currently, 42% of all bridges are at least 50 years old, and 46,154, or 7.5% of the nation’s bridges, are considered structurally deficient, meaning they are in “poor” condition. Unfortunately, 178 million trips are taken across these structurally deficient bridges every day. In recent years, though, as the average age of America’s bridges increases to 44 years, the number of structurally deficient bridges has continued to decline; however, the rate of improvements has slowed. A recent estimate for the nation’s backlog of bridge repair needs is $125 billion. We need to increase spending on bridge rehabilitation from $14.4 billion annually to $22.7 billion annually, or by 58%, if we are to improve the condition. At the current rate of investment, it will take until 2071 to make all of the repairs that are currently necessary, and the additional deterioration over the next 50 years will become overwhelming."
I don't know in what rich poor EU country you live, but in my "rich country" bridges are basically left to their own devices until a critical problem occurs and then they hastily start repairing it. In some cases they've been repairing bridges for decades that way. Some have recently finally actually been replaced or are being replaced. But nobody is going out and replacing a bridge that isn't on the brink of collapse and held up by "essentially duct tape".
There are metal bridges over 100 years old still in service today, including a few you've heard of. Do you know this specific bridge was replaced for this specific reason, or are you just making stuff up?
The question was why this specific steel bridge was replaced. Not "what are possible reasons someone could replace steel bridges?" and it's absolutely not "basic materials engineering" that every bridge needs replacing after a fixed amount of time due to corrosion.
So again, do you know this specific bridge was replaced for this specific reason, or are you just making stuff up? Because bumping in on a specific question with a generic answer without any knowledge if that applies to this specific case is making stuff up.
The hostile tone is because you're talking complete nonsense with great arrogance.
So your convincing evidence for the claim that "plenty of poorly designed steel bridges from the 19th century have collapsed" is a single example of a bridge that collapsed because it was designed "less extensive and robust than [..] previous similar designs"?
Or is your claim a mere circular argument, since we can deduce that a steel bridge was poorly designed if it has since collapsed?
Well to paraphrase a common saying, it's easy to build a bridge that stands, but it's difficult to make sure that is so optimized that it's on the verge of failing but still somehow stands.
The bridge was built during a trend to build wooden apartment houses here in Sweden, and probably all over Scandinavia.
This fad has now passed and there have been several news stories about what a bad idea it was. I guess they were trying to get back to using more natural materials.
That's true, I had missed how popular they had become. My brother briefly lived in a wooden apartment building around 2017 and after they moved out I noticed a few criticism of the new wooden trend. Then I just lost track of it.
The trend goes back to 2014 even, so it wouldn't surprise me if this wooden bridge built in 2012 was part of that whole wave.
You will see wooden covered bridges from 1895 that last a long time too. It is not a material choice problem here, it’s the design and how the members are laid out.
Tretten Bridge was designed while building regulations in Norway were in transition from a national system to European codes.
Provisions for this transitional period enabled the project to follow the older national standards, which unlike the Eurocodes did not account for block shear failure.
Kind of. I should have thought the engineers involved would have been good enough to design a bridge that would have lasted more than a decade, even if the regulations weren't as rigorous.
One would hope... but corporate structures can apply a LOT of pressure which can end up impairing judgment or resistance to decisions by higher-level executives. It might or might not be the issue here, but it's definitely been seen in past disasters.
(It's similar to the more readily/well understood "peer pressure", but even more insidious.)
I translated some of the norweigan paragraps that include "estetik" but I can't figure out if they mean "they should have used steel" or they mean "the diagonal members should change direction to keep them in compression" or both.
> En kombinert stålbjelkebru med betongdekke var mulig, men ble utelukket på grunn av estetikken og begrensningene i veigeometrien under og på brua.
which states that aesthetics and road geometry together ruled out a combined steel and concrete bridge.
there's also:
> Artikkelen beskriver avslutningsvis at det i pre-designfasen var flere retningslinjer knyttet til utformingen av brua. Videre står det at teamet som prosjekterte brua ble påvirket av andre prosjekter på den aktuelle tiden, og at Oppland fylke var et skogsbruksfylke der tre har vært et viktig byggemateriale.
Dette, kombinert med fordelene av det lette dekket, medførte at en trebru
var det beste alternativet. Kombinasjonen av tre og stål gjorde det også mulig å utforme brua som ønsket, uten ekstra avstivning ved aksene.
But in the end the above just amounts to "they could have built a conventional bridge but wanted something prettier": basically aesthetics contributed to the collapse because it was the primary reason they built something novel.
Had there instead been some site specific geometry that forced a novel solution, one wonders if they had blamed that...
Well, either would work: Steel can be easily fitted to take tension loads; Or the wood could be oriented to be in compression, with the ends butted against other structure thus relieving the bolts of most of the load.
What was done instead concentrated the tension stress onto a small central core section of the member, with rest transferred to wood grain-aligned, therefore weak, sheer faces within the timber.
Thanks for the video: To anyone who's spent some time working with wooden garden gates, that's enough to tell the story.
The idea that a "strong focus on aesthetics" contributed to the failure of a bridge doesn't make any logical sense. Employing a strong focus on aesthetics doesn't preclude also having the necessary focus on stability and safety. Bridges fail because they were not designed or engineered properly.
I don't agree; to me it states they were so focused on aesthetics that they weren't able to see structural flaws. Like tunnel vision. Seems like the best way to state this phenomenon IMO.
It can also easily mean they were willing on taking risks, like using unproven techniques, skirt close to minimum safety requirements or even ignore certain rules, just so it would look prettier.
Building pretty things on land is significantly easier than building them over water. Engineering is the art of tradeoffs. You want to pick your "aesthetics" battles somewhat carefully. Which also means you're going to want some _solid_ justifications for incorporating them into a retrofit.
If you look at the picture while it's standing, the design has the diagonal braces all running the same way. Any homeowner who has knocked together a wooden gate could recognize that as abnormal. If the bridge were standing, I might think "huh, I guess the did the math and it works fine like this". But since it's scattered across the riverbed, I guess they didn't.
You can strongly value two (or more) things, but when you decide to focus on something, as I understand the term, you necessarily preclude focusing on another thing.
They said "strong focus" which implies there is a spectrum of focus and that everything falls on that spectrum of focus. I disagree that any amount of focus precludes any focus on something else, especially in this context.
On second thought, a camera can only focus on one field. So it would make sense if our language only allowed one focus. But what if we had multiple cameras? Or multiple teams or engineers designing a bridge?
What’s odd to me is it wasn’t even too aesthetically pleasing with the wood. Sure it looked a little unusual but I don’t personally think a plain steel bridge looks all that much different, and certainly not much worse.
That's so strange! Looking through the photos on the page, there's one showing the bridge still intact.
It's almost as if someone accidentally flipped the materials -- the members that work in compression are were made of metal, the members under tension, out of lumber. That's the opposite of what each material is naturally strong at.
Actually wood is stronger in tensile: "tensile strength of soft- woods parallel to grain at 12% moisture content generally ranges between 70 to 140MPa. The compression strength is lower and is usually in the range 30 to 60 MPa."
Steel is similar in strength both ways, although it varies a lot depending on how it was annealed. (The harder the metal the better compression is vs tensile.)
This is true but the main concern with compression loads is buckling, which generally happens well before the material yields to normal stress. This means that compression members need to be much stiffer in bending, and so generally bulky and geometrically large, with a big moment of inertia. Whereas tension members can basically just be wire rope.
Wood can easily be built up into a much larger cross-section than steel for the same cost and less weight, so it makes sense to use it for compression loads.
Never seen a truss where the diagonal members are all one direction like that. Also bit weird that the strongest part of the bridge is not the middle of the longest span, but it does not appear to be cantilever. Disclaimer: I am a mere Poly Bridge player.
Nor of any other material. Between the insanely shallow truss depth at the right end of it, and the "can't tell compression from tension" decision to slant all the diagonal members in the same direction - that bridge is a poster child for "I Flunked Engineering 201".
I almost feel like intuition tells you that. It literally looks like it can fold down flat. A regular truss bridge looks like a honeycomb, straining, but balanced.
that's a pretty political spin. if i remember correctly the bridge in florida was entirely feasible but they got the pre-tensioning and assembly wrong.
> The new pedestrian bridge was designed to connect the campus to student housing in a dramatic, sculptural way and also to showcase the school's leadership in the ABC method of rapid bridge construction.[16][17]
And from my recollection of coverage at the time - FIU's administrative pressure to deliver their dramatic & leading-edge-construction bridge, quick and cheap, lead to all sorts of corner cutting in the engineering & fabrication.
To me the root cause was they just could not see a way to inconvenience even one single driver ever. They had to grade separate pedestrians from cars over a freeway and a gigantic parking lot. Universities should be pedestrian focused.
The bridge could have been designed correctly. But the fundamental issue was the bridge didn't need to exist.
I think that's more of an auxiliary issue than the "fundamental" one. Space is limited, and a nice (and non-collapsing) bridge could be more convenient for pedestrians than however things would be laid out on the ground even if there wasn't a road there. Safe bridges should be able to exist, whether one would have been needed in this exact spot in an alternate reality or not.
It's also very telling for you to condense "a freeway and a gigantic parking lot" down to "one single driver ever." Five motorists wouldn't have been killed by the collapse alone if "one single driver" was the only one who ever used it.
Your Tampa Bay article does nothing to refute the claim that the bridge was designed by an all female team. All it does is state that men also worked at both companies and were also in leadership roles therefore it couldn't have been led by an all-female team. As though the companies were so small every employee was involved in every project.
If this is the best evidence you have it's not very good. And snopes is a laughably unreliable source I won't even entertain their bullshit.
What on earth are you talking about? The engineer of record for the project was a man. And I don't understand the implication of your comment – do you really believe that not only was the engineering team led by women, but they also refused to collaborate with men in any capacity? The project had to be approved by a PE at some point, do you think that a female PE is somehow less capable than a male one?
The female engineer angle was never true, it was a 4chan hallucination. Something they lied to each other so much they forgot it was a lie
Look up the phone call / voicemail between FIGG engineer and FDOT, in which the FIGG engineer describes the cracking and says it isn't a problem and they're proceeding. The engineer was a man.
William "Denny" Pate was the engineer who stamped the drawings. After the incident he says his wife accidentally put his phone through the laundry, so he couldn't provide his texts for evidence. Hmmmmmm.
> "A short construction period, span lengths and reuse of existing foundation were framework conditions for the planning of the bridge," it continued.
> "These framework conditions, combined with the choice of material and a strong focus on aesthetics, contributed to the structure not being robust."
Given that it doesn't look that remarkable it seems odd that a little asymmetry couldn't be accounted for. Or was someone out there saying "we'll never build symmetric bridges, our river is too good for them..." Because the rest of the article makes it sound more like an engineering failure.
Err, the actual quotes make it sound more like plain old engineering troubles, made more complicated by the discrepancy between older and newer building codes.
> "A short construction period, span lengths and reuse of existing foundation were framework conditions for the planning of the bridge," [the report by the NSIA] continued.
I understand why a design website would emphasize the design aspects though.
Function over form is a false equivalency, a modernist fetish.
Architect's first commandment should be to strive to a perfect integration of beauty, usefulness and durability. There are many real world examples, so it's not a trade-off.
Plus, that "strong focus on aesthetics" seem to be a throwaway comment in the report, and it is disputed by the design studio who built the bridge.
It presupposes a false _dichotomy_, one that misunderstands the nature of beauty. A building's beauty will in large part be a matter of its _function_. It it not just a matter of decoration, which is important, but does not exhaust the aesthetic concerns of an architect.
The Pantheon in Rome is an especially nice sign of contradiction, but it is hardly alone.
We are human beings, not some consumerist homo economicus that exists merely to eat, shit, drink, and copulate and in a bestial manner. Let us care about the beauty of our environment. This can be done even within means. Beauty is a transcendental. Those who attack it, or insult it, who denigrate it, who dismiss it are misanthropes and enemies of the entire human race.
Unsurprisingly, this is Wurster Hall, home of the Architecture School (aka "College of Environmental Design") at UC Berkeley: https://www.sosbrutalism.org/cms/15892267
Horrific, but salvageable. Put on a wide overhang flat roof, so rain no longer streaks down the wall, and wash/paint it. Then, it will just be a large no frills classroom building. Not great, but no longer offensive either.
Ive never understood why this style of architecture is seen as "horrific" and "offensive". It looks nice. I like to see the materials a building is made of. I am so sick stucco and paneling trying to hide the material a building is made of. If you want to paint it paint a mural. Why must everything be sterilized and flattened.
Because they didnt bother to put a roof on it for ideological reasons (postwar architects were obsessed with cubes, purely because it made a statement), so rain streaks down and those skidmarks looks awful on big concrete slabs.
So they at least need to wash it and put on a roof that prevents it from happening again.
Apart from that, this building is fine overall.
It's odd though, because I would call this building sterilized and flattened as well!
The rain streaks look great to me as well! Its kind of like a pair of well worn leather shoes has creases and lines where the foot bends or how a well worn pair of jeans fades on the knees and wrinkles. Not that I am against a roof for this building, or even adding some materials like brick or maybe timber could be interesting.
I think this about lots of 'brutalist' buildings: theyre gorgeous as is and might be improved a bit and receive less hate if they used more materials than just concrete and glass. Brick, Timber, and stone even after all people love all the Frank Loyd Wright stuff and he used plenty of raw materials.
Legitimately makes some prisons look inviting. The bare concrete, which the dirt makes it look like it is rotting away, gives it the charm of an uninhibited ruin. Even on the brightest days the shadows of the building will make you inexplicably cold, while the oppressive outside has cut many conversations short.
Any good design is a collaboration of art and engineering, where the end result accomplishes the technical requirements and integrates itself into the world around it in an appropriate way. Neither of these can be considered alone, function has a form of its own, just like form has a function of it's own.
Architects aren't structural engineers and only in dialogue good infrastructure can be created.
I’m fairly certain good ‘infrastructure’ can be engineered. If you want something pretty that integrates into the world around it’s not solely infrastructure any more.
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The ironic part is "The bridge replaced a steel truss bridge built in 1895 at the same location". Engineers in 1895 knew how to use steel trusses and built a bridge that lasted 100+ years, and in 2012 they decided to use glued wooden beams and it fell apart in 10 years.
Well perhaps Plan Arkitekter and Norconsult can take a trip to the archives and see what the engineers in 1895 knew before building any more structures.