Italy bridge: Genoa motorway collapse kills at least 22 | Hacker News Reader

Italy bridge: Genoa motorway collapse kills at least 22

bbc.com

309 pointsrubenbe188 comments

I was looking for the site of the bridge on OpenStreetMap, but couldn't find it. It took me a while to realize that someone already took it off the map within an hour of it collapsing.

Impressive (and correct), if a little disconcerting:

https://www.openstreetmap.org/#map=17/44.42585/8.88840

All the access roads have been disabled too.

Googles map with sattelite and traffic updates https://www.google.co.uk/maps/@44.425374,8.8839348,2984m/dat...

It has a quite a good 3d render of the bridge and street level view if you zoom in

If you zoom out, it is still there. I guess it might be a cache https://www.openstreetmap.org/#map=16/44.4262/8.8879

Lower zoom-levels are cached for a longer period than higher ones for performance reasons.

OpenStreetMap per se is, in the pedantic/correct sense, not the bitmap tiles, but the database used to generate them.

bridge=collapsed

damage:event="2018-08-14 Genova Collapsed Bridge"

https://www.openstreetmap.org/way/616904168#map=18/44.42599/...

The power the OSM tagging system.is capable of astounds me over and over. Looking for benches with backrests in your area? There's a way to encode the locations of those in OSM!

Are you allowed to bring your bike onboard this ferry? Does it have a toilet? All answerable with OSM!

Of course, the downside is a diverse set of opinions on how to tag stuff, but I get the impression OSM editors are aware of the vast public benefits of having an agreed-upon way to tag things.

What I really, really, like is location of all the public toilets. This is precious information while exploring big cities.

You're welcome :-)

I wonder if there's also @Anonymaps on HN...

xkcd was premonitory https://xkcd.com/2029/

Wikipedia was very quick, too.

https://en.wikipedia.org/wiki/List_of_bridge_failures#2000%E...

The italian entry for the bridge was semiprotected as soon as the news broke, but now I see there's a enwiki standalone entry https://en.wikipedia.org/wiki/Ponte_Morandi

I removed it as soon as I got the news. First thing is to have the routing software updated and handle the emergency. I live in Genoa ad I work in a logistic company, and I'm an OSM contributor since 2011 :-)

Well played. Despite the tragedy, that must be your finest OSM hour.

I prefer when I tweeted CopernicusEMS during the 2016 earthquake... http://emergency.copernicus.eu/mapping/sites/default/files/f...

Apparently in Ancient Rome, the ceremony of opening of the bridge consisted of placing the Engineers and Architects who built it to be under the bridge and marching an army Legion over the bridge. Today we have courts and laws to deal with this but every story like this is a reminder of responsibility put into Civil Engineers. But also it serves as a reminder that any Engineering discipline, including Software, has to have accountability and ethics standards.

edit: I'm not blaming anyone for this tragic accident. The cause will be found eventually. What I mean is it's important to remember how your work may impact lives, regardless of what that work is.

Apparently this was built in the 1960's. Not sure if lack of maintenance is to blame or original design.

The average lifespan of a bridge is about 70 years.

And requires no maintenance?

They definitely require routine maintenance and inspection.

The Nondestructive Testing article I linked to in another comment said "significant environmental damage requiring repair typically occurs before the average bridge reaches mid-life."

It would be very interesting to know how bridge metrics (length, load specification, etc.) relate the longevity. Of course, some bridges last for centuries, but some last for decades. This is an order of magnitude!

Spoiler: they don't, yet they do, Theseus' ship-style. For all the centuries-old bridges still in use around here, there's only a few bits and pieces left from the original, the rest has been replaced multiple times over as a part of maintenance.

The difference here is probably maintainability: for a stone arch design, you can prop it up for safety, replace a few stones, and voila, like new. For a cable-stayed and/or concrete design...not really. In other words, the bridges that have "lasted for centuries" have hot-swappable parts ;)

Isn't that just a function of when most highway construction took place in Europe and the US?

Lifespan, not age. Most bridges where built after 1945 with a life expectancy between 70-75 years.

https://www.nde-ed.org/AboutNDT/SelectedApplications/Bridge_...

The Kingston Bridge in Glasow, which opened in 1970, has had to have a huge amount of work done over the years - there were problems with both the original design, the actual construction and the face it was carrying far more traffic than expected:

https://en.wikipedia.org/wiki/Kingston_Bridge,_Glasgow

Edinburgh's Forth Road Bridge was also partially closed in 2015

https://en.wikipedia.org/wiki/Forth_Road_Bridge#Structural_i...

Before the fall there was already a lot of talk about the constant, excessive maintenance and repairs needed by the bridge; there was discussion if the best way to go forward was a major overhaul or just demolition (of course such talk could have gone on for years or decades before anything was made).

In the '80s the support structures were already reinforced and apparently it took years of filling the subsidences in the asphalt surface for it to stabilize and provide a level surface for the cars.

I'm not a structural engineer and I am in no position to judge, but there definitely was the suspicion that the design of the bridge was flawed, even before today.

>I'm not a structural engineer and I am in no position to judge, but there definitely was the suspicion that the design of the bridge was flawed, even before today.

The bridge was - at the time - a bleeding edge of concrete technology, designed by the greatest expert in concrete (and pre-compression) in Italy (and probably in the world), Riccardo Morandi.

He designed also the Maracaibo Bridge:

https://en.wikipedia.org/wiki/General_Rafael_Urdaneta_Bridge

Allow me to doubt that the design had structural flaws, though it is true that at the time some aspects of long span pre-stressed concrete structures were not yet fully undestood, namely creep and shrinkage:

https://en.wikipedia.org/wiki/Creep_and_shrinkage_of_concret...

Which have definitely increased the need for maintenance, shortening the expected working life of similar structures.

However from the little it can be seen from the photos that have been posted here and there, it seems like the initial point of failure was not the bridge (meaning the deck) but rather the pier, causing the two adjoining spans to collapse.

Experts do make mistakes sometimes

According to news reports, likely immediate causes include lightning striking one of the pillars, wind and overload. It seems quite certain that the bridge was somewhat decrepit, and some media report that consolidation work was in progress.

How can lightning cause a bridge to collapse?

I don't see why one would jump to blaming the engineers from the 1960's instead of the very government bureaucracy that was responsible for funding the maintenance and oversight of the bridge for over five decades. I do wonder if it is possible the "violent downburst" in the article could have created enough force on the bridge to push it past it's load-rating though.

edit: I should add that it could very well be the fault of an engineer from 50 years ago (poor design, implementation), but this just happened today and it will take a while for people to figure out what really happened, and without any other data my first inclination is to think "poor maintenance" as that is what Occam's Razor (simple: lack of maintenance is very common these days, at least in the US: prepare to be afraid of many bridges you drive over[0]) and then there's the whole downburst thing that seems vaguely plausible for now.

edit2: "The U.S. has 614,387 bridges, almost four in 10 of which are 50 years or older. 56,007 — 9.1% — of the nation’s bridges were structurally deficient in 2016, and on average there were 188 million trips across a structurally deficient bridge each day. While the number of bridges that are in such poor condition as to be considered structurally deficient is decreasing, the average age of America’s bridges keeps going up and many of the nation’s bridges are approaching the end of their design life. The most recent estimate puts the nation’s backlog of bridge rehabilitation needs at $123 billion."[1]

[0]https://www.infrastructurereportcard.org/americas-grades/

[1]https://www.infrastructurereportcard.org/cat-item/bridges/

I don't perceive any blame in the comment you are responding to, only observations relating to the history of bridges and the responsibility that comes with it. What did you feel was assigning blame when you read it?

Whether or not it was intended, the entire comment implies exactly that - particularly with the call to the responsibility, ethics and standards of the civil engineers.

For example, if someone dies in a car crash, it's a little out of context for you to focus on the responsibility and ethics of the car designer over and above the circumstances of the crash. Usually the latter focus is for when there's concern about said ethics and responsibilities.

See basically what wastedhours said.

> I don't see why one would jump to blaming the engineers from the 1960's instead of [...] the maintenance

Unfortunately, in this case it's probably a bit of both. A bridge that was the direct precursor to this one, collapsed after a few years. Maintenance expenses for the Genoa bridge were already off the charts 20 years ago, and likely went down after its privatisation. It had been described a few years ago as a "failure of engineering" by several people.

Chances are that everyone involved in its maintenance knew that shit could hit the fan at some point, but there was no political will to close one of the main city arteries, and probably no budget (or even space, in that city) to build a replacement either.

Being a civil engineer can be tough, especially in complicated countries like Italy. The main architect is long dead; the country has been broke for decades now; the elements are unforgiving; and people are more than ready to lynch you if shit happens.

I still think "failure of engineering" is too convenient of an excuse, but I concur with your points regardless.

> the country has been broke for decades now

Really?

Broke, no. Choked by debt interest, yes.

>Broke, no.

And waste of resources. But broke no, thanks €!

Interest on public debt (which is 130% of GDP, inferior only to Japan [1]) makes it basically impossible to have any sort of expansive economic policy. Since the '90s, any investment has to be financed with cuts elsewhere (this has even been enshrined in the Constitution, for good measure). The state routinely struggles to pay for schools and police cars, and to hire replacements for retiring civil servants or doctors. One year, the state literally took a chunk of money out of all bank accounts overnight; a repeat has recently been considered.

The country is broke, but our survival skills are so proverbial that the markets more or less trust we'll always come up with enough money to keep going. The day this stops being true, we'll go the Argentina way very quickly.

> One year, the state literally took a chunk of money out of all bank accounts overnight

To be fair, that was 1992 so way before the euro. The problem is that ratings are easy to send down, but very hard to bring back up. Currently they are just two steps above junk, (despite having had pretty low interest until a few days before the current government swore in). Even just a single downgrading would be bad, two would lead to a massive sell and basically a disaster way worse than the Argentinian crisis.

I never mentioned the Euro, the country was on life support well before that. In many ways, the Euro was actually the first step towards a "get out of jail" card. Unfortunately, the second one (Eurobonds) hasn't happened yet.

Yes, I agree. I just wanted to say that the economic situation at the time of the "prelievo forzoso" was very different. I agree with your definition of the Euro as a "get out of jail" card, too.

come on, Italy is not broke, not more than Spain, US, UK or Japan.

Italy is currently seen as the EU country most likely to collapse financially. There were severe doubts about what was going to happen when a new government was inaugurated a month or so ago. Spain is also not doing very well, but not in short-term danger. US and UK are doing much better (I don't know much about Japan).

Even worse is that several of the major Italian banks have a large exposure to Turkey including UniCredit. Italy has the worst youth unemployment in the EU[1]. Consequentially, there was a large amount of drug use in the city I lived in.

https://www.thelocal.it/20170718/italy-european-union-most-h...

I don't feel like the US is doing better. The public debt as a percentage of the GDP isn't the only public debt number that matters. The absolute number and the public debt per capita also matter.

We're drifting off topic, but as long as the dollar remains the world's reserve currency, the US nearly can't fail financially.

You must have missed the news these last few years.

As soon as the markets get a whiff of potential instability in the country that would cause a deviation on the austerity policy imposed by the EU, the credit spread on goverment bonds skyrockets.

And with some good reason, as pre-EU governments used devaluation of the Lira to boost the exports and increase GDP (of course increasing inflation) on one hand, and kept borrowing money on the other, instead of trying to address historical problems like under-development of the South, unsustainable social security, rampant tax evasion, corruption in local administrations.

Even if currency devaluation were possible these days (basically only by leaving the EU), it would have to face a much more globalized economy than last century, where many exports depend on parts manufactured abroad, which would be suddenly more expensive to produce...

Italy is not broke as long it can pay interests on its debt, but every fluctuation in the global economy affect Italy way more than UK, US or Japan.

> A bridge that was the direct precursor to this one, collapsed after a few years

Do you mean the one which was hit by a supertanker?

in a way that was not accounted for, yes. Other bits of the bridge were reinforced, apparently, but not that one. It is significant because the Italian bridge also had to be signficiantly reinforced at the base, about 20 years after construction.

I would never blame an Italian civil engineer. They are amongst the best of the world.

It's most likely a corrupt contractor paired with a corrupt politician to blame. They usually use bad or sloppy concrete, or not the planned amount of steel the engineer demanded.

The good news is that Trump promised a massive reinvestment in U.S. infrastructure. I'm sure that's right around the corner...

>56,007 — 9.1% — of the nation’s bridges were structurally deficient in 2016, and on average there were 188 million trips across a structurally deficient bridge each day

This number is kept higher than it needs to be for economic/political reasons. If your bridge is about to fall down at any minute it's easier to get federal dollars (or justify using your existing dollars) to build a new bridge. As a result there's lots of bridges that are past due with shovel ready plans for replacement but the local/state gov is just waiting for it to become a crisis so that they don't have to pay for as much of the fix. If the replacement bridge requires taking private land, disrupting traffic, etc, etc. there's even more reason to wait for a crisis.

A bridge can be considered "structurally deficient" if destroying one member can cause the bridge to collapse, but the bridge can otherwise last decades or centuries more. The solution being stop letting idiots drive oversize loads on them and they'll be just fine without spending billions of dollars on replacements.

I understand the idea but there's a threshold of diminishing returns when putting too much pressure on a position. Lots of doctors work with lawyers in mind, and will refuse tasks because of risk. Other fields have similar subpar performance due to high responsibility stress.

We need to increase quality but not at the expense of people working.

As a former civil engineer, at least in the US you need a license from the state to stamp a design before anyone will build it, so accountability is built into the process.

Its actually stressful and the pay isn't that great. I did mostly landfill design which is a little different, but slope stability and retention pond calculations were always checked and double checked.

Though there is always ongoing maintenance which would be the owner responsibility.

Sure, there's always a level of responsibility but at one point it becomes unfair and counter productive.

Engineers in Canada wear "iron" rings that are meant to be representative of this responsibility[0]. While not actually true, most of the time people talk about it they claim the rings were originally made from a failed beam of the first Quebec Bridge[1], improperly engineered.

My wife has three pieces of jewelry- engagement ring, wedding ring, iron ring. She doesn't tell me which one she loves best.

[0]https://en.m.wikipedia.org/wiki/Iron_Ring [1]https://en.m.wikipedia.org/wiki/Quebec_Bridge

That's actually a really cool tradition imo. Never heard about it until now.

Thanks for that!

I had thought it was a North American thing, if not a worldwide thing. Canadian speaking. Goes to show that it's easy to assume the world is the same everywhere.

American Universities with engineering departments have an Order of the Engineer ceremony and I recall some people got rings I think. It's been a few years though.

As a cannuck, I can chuckle at the fact that one of our Ontario bridges lasted 42 days before it failed.[1]

[1]https://globalnews.ca/news/2957484/design-improperly-tighten...

Let's not jump to conclusions.

The only facts we know are that the bridge collapsed and a bunch of people died. Let's not turn the conversation to "blame the engineer".

Accountability and ethics are the yardstick everyone is measured by.

Blame, no. But going into the cause is more than warranted.

Seemed like an Italian academic called it an "failure of engineering" two years ago, and another construction of the same engineer was reported to have collapsed in earlier years.

Naah, this is folklore:

https://skeptics.stackexchange.com/questions/18558/were-roma...

As a matter of fact if you have a legion marching on it, almost any bridge will collapse, there is a reason why, when soldiers cross bridges they are ordered to "break stride" in order to avoid possible issues with resonance of the structure.

And of course, while placing architects and engineers under the bridge was "fair", the poor soldiers were innocent (and at the time among valuable resources to society) so their lives wouldn't have been deliberately risked.

There are some (unconfirmed) reports about the architect standing below the bridge when the scaffolding/support was removed, however.

I think I’ve read something similar about the ex-dictator in Albania, who would place engineers into bunkers they've constructed and then fire on them to see if they hold

EDIT: found a source, seems to be a true story

https://www.balkanride.com/2017/03/07/albanias-concrete-bunk...

It’s like dogfooding.

This was the issue with the "Millenium" bridge in London, renamed unofficially as the "wobbly" bridge.

Because of the nature of it's construction people would over time start to sync their steps, the more this happened the more the bridge swayed and the more people synced their steps.

It was fixed by adding dampers.

https://en.wikipedia.org/wiki/Millennium_Bridge,_London

https://en.wikipedia.org/wiki/Angers_Bridge : Soldiers create resonance on a brdige, making it collapse.

There is actually little evidence here that a resonance excited by marching soldiers caused this bridge to fall. The article says that, as usual, the soldiers were instructed to break step when crossing. The article cites a powerful thunderstorm, the effect of strong gusts being 'caught' by the massed soldiers on the bridge, and corrosion of the cables at their anchorages, as likely causes. A survivor reported that the soldiers were stumbling around as if drunk, and could barely stand. There was some speculation that the motion of the bridge caused the soldiers to respond in a coordinated way that exacerbated the swaying, but lurching from side to side is hardly marching.

Contrary to what the grandparent post says, few bridges are susceptible to being brought down by marching.

On the note of bridge resonance, one can not forget the Tacoma Narrows Bridge: https://www.youtube.com/watch?v=j-zczJXSxnw

If anything, the way that bridge wobbles before collapsing is pretty assuring - it’s unlikely I’d enter a bridge even remotely as unstable!

I was talking to a colleague today and I made that example I remembered from my physics course done on the Halliday-Resnick textbook https://en.wikipedia.org/wiki/Fundamentals_of_Physics

I recall that we always had to break stride when marching across bridges, but I also recall that this has long been debunked, a properly designed bridge is in no danger at all from people marching across it in step.

There was that British bridge, but it was suspension:

https://en.m.wikipedia.org/wiki/Broughton_Suspension_Bridge

It is easy to see how a suspension bridge would resonate fairly easily. Also see the Tacoma Narrows bridge.

Much software does not have lives depending on it and it would be wasteful to treat it as though it did.

Software in cars, planes, other types of transportation. Medical software, military programs, the software used by civil engineers,..

There's probably lots of software where it could play part

Not to mention the phone apps that keep users so addicted they can't look away to operate heavy machinery.

If a crane falls over because the operator was playing Candy Crush, I think that can be placed squarely in the category of "user error".

> Not to mention the phone apps that keep users so addicted they can't look away to operate heavy machinery.

Or cars while they are crossing the roads. I see this daily.

Oh, good point. Do you have any statistics handy on how many people are killed and maimed by inattentive pedestrians? It would be useful for contrasting with [0].

[0]: https://crashstats.nhtsa.dot.gov/Api/Public/Publication/8124...

With software the pertinent metric is the number of quality-adjusted life years (QALY) lost. Most software systems don’t directly kill people but the amount of stress and wasted time incurred by poorly-designed dysfunctional systems does add up.

> With software the pertinent metric is the number of quality-adjusted life years (QALY) lost.

Except that QALY is a bullshit metric based on economic doctrine that is unsupported empirically (and, arguably, in their specific application in QALY, outright disproven.)

Perhaps, but you have to weigh that against the cheaply-made programs that save people a lot of time but would never have got made (or would be decades late) if the author had been obliged to follow "best practices".

As an aside, nobody making a claim about life lost uses QALY (or any other metric that devalues old people dying slightly sooner than they otherwise would have) because it doesn't make for impressive headlines, sound bytes or claims. Much more impactful to say that X people died from exposure to X than to say a bunch of people in their 70s and 80s and a couple in their 50s died of <some disease that is a result of X exposure> because they were exposed to X. Reality rarely makes for impressive headlines.

> Nobody making a claim about life lost uses QALY because it doesn't make for impressive headlines, sound bytes or claims.

And because the actual measure only addresses, even in principal, quality related to health conditions (though you could apply the basic methodology to construct a broader quality measure), and because the entire theoretical construct by which it assesses quality adjustment is, to put it mildly, suspect.

Or it might not have been built to specification.

I know of an instance of contractors having the rebar inspected by the engineer and then moving the reinforcement to the next part in the sequence to be constructed. The engineer caught them at it because he got up very early to go sea fishing and happened to walk past the site. Incidentally this anecdote happened in Italy in the 1960's, maybe it was a widespread practice.

This is most likely the case. It was either not built, or maintained to specification by contractors. This is an issue most of the time something fails like this. Remember, in construction, the engineers who designed it, aren't the ones who actually build it, it is contractors. Yes, there are a lot of compliance things like construction oversight and even using a 3rd party company to access the risk during the design and build itself.

This sounds like a case where the maintenance was not carried out properly. Or the procedure the contractors were doing was wrong. Then a storm came and it exceeded its limits.

Source: I'm not a civil engineer, but I've lived with one for some time and know a bit from conversation.

Edit: I don' mean to just say, "it's the contractors" fault. It could have been higher up with budget cuts and telling the contractors, don't do this because we don't want to spend the money. This is the exact reason of having a 3rd party firm monitoring it as far as risk assessment and compliance goes.

Another Edit: The civil engineer I live with said the rain or lighting should have had no effect, UNLESS it was a foundation issue. Which another commentator mentioned the foundation was undergoing maintenance at the time? Seems to be the most likely scenario.

This happened when the municipal archive in Cologne, Germany collapsed. There was a subway construction site under the ground. Apart from problems with groundwater, iron reinforcement material for the tunnels had been stolen. The whole archive with many documents from the middle ages was reduced to rubble, and two lifes were lost. Had that happened a few days earlier, hundreds of people could have died.

> Work to shore up the foundation of the bridge was being carried out at the time of the collapse

Seems like a more plausible explanation on the face of things. Lots of highly publicized incidents in the US of fatal bridge and overpass incidents due to construction. While I assume these are overseen by an engineer, there are a lot of things out of their control that can go wrong when people are actively using the structure under maintenance.

Yes. On the radio this morning they mentioned that the bridge had been refurbished a couple of months ago. It seems like a big red flag to me.

Engineers standing under the bridge during tests is still a tradition

See from 16:45m https://www.youtube.com/watch?v=KHjC0l9nJOg

Looks like a dramatization (I didn't watch all of it), and could also be propaganda (communist in this case).

> I'm not blaming anyone for this tragic accident

Well, you're blaming the engineers.

If you say "I'm not saying it's the engineers' fault, but engineers should remember that they're responsible for what they build", it's like blaming the engineers.

> If you say "I'm not saying it's the engineers' fault, but engineers should remember that they're responsible for what they build", it's like blaming the engineers.

No, it's not. I did not assign blame to anyone, that is what the court will do.

You may argue I insinuated it might be the engineers fault. Well I did and it might. I'm an engineer myself and many others here are too, so it's a relevant angle for us.

I have an degree in mechanical engineering and our teachers always reminded us that worst case scenario for our work is a collapsing bridge.

There may be complex lessons in this. Reinforced concrete has tended to reach end of life sooner than expected which has some serious implications for structures both built and so far only proposed.

I thought the strong increase in heavy goods vehicles and traffic was the main cause for the widespread problems with bridges from the sixties?

I used to work under this bridge. Everybody knew that the bridge was unsafe. However, the local government didn't want to close the bridge because it was critical for the community. Some activists didn't want to close it because they didn't want to build a replacement. So disasters happen, shit always happens. But this was not a disaster, something unknown, this is manslaughter from my point of view. I wish somebody pays for it, but this won't happen.

Almost the same thing happened in London a year ago, local government was too afraid to make any action and improve the situation. No one is gonna to pay for it, unless it's you with taxes.

https://www.independent.co.uk/news/uk/home-news/grenfell-tow...

Until I saw the link you posted, I thought you were talking about Hammersmith Flyover, which had to be closed for several weeks to strengthen it after they found an alarming number of cracks.

They still don't have a long-term plan to replace it afaik, despite the strengthening works only being a temporary measure.

> temporary measure

Everyone knows that temporary is a new word for permanent.

//TODO: temporary workaround, fix ASAP, etc.

The difference between this and grenfell was that here the local authorities had been acknowledged of the status of the bridge via official documents. The bridge suffer a major redesign in the '90s. I cannot believe how nobody cared about it.

Sorry but I really don't understand how this applies to Grenfell. It's not like there were any major maintenance issues with the tower that were ignored by the council and ended up causing it to fall down. The problem was that some new cladding was installed which didn't follow safety regulations and thus compromised the (in principle adequate) fire safety provisions, and that turned a small flat fire into a disaster.

What he means is that also in the case of the Grenfell towers "everybody knew it was going to happen". Except it's not true (as I bet it's not true in case of the Genoa bridge as well), as among the thousands of angry complaints that the residents sent to the council in the years before the catastrophe, apparently none was about the choice of the cladding.

Firemen all over Europe had warned loudly about that type of cladding. In Germany, it is illegal to use it in multi-floored buildings exactly because of that reason.

There are probably many more aspects which led to the Greenfell disaster. The building having a sprinkler system would have prevented it. The firemen having an appropriately high ladder rtuck or aerial work platform would have made it almost comfortable to salvage the trapped 80 people. Some waited many hours before they borned to death. The firemen in London, Kensington didn't had a high ladder. Because of cost.

Grenfell isn't the same, a considerable amount of money had been spent renovating the building.

Grenfell's quite different to this. More similar is the Hammersmith Flyover where they recently had an issue with a post tensioned 60s structure, and corroded tendons snapping. In that case drastic action was taken, closing the structure (even though it carried arterial roads) and instigating a programme to replace the tendons gradually.

A common issue with many of the 1960s reinforced concrete structures is the difficulty of inspecting key structural members (e.g. encased tendons which may have also been the case with the Genoese bridge), lower standards than current (so the distance to reinforcement is less and corrosion is more likely) and maintenance regimes with lowered funding to repair an increasing number of deficient structures.

> Everybody knew that the bridge was unsafe.

Oh yes? So I suppose everybody also knows why it collapsed, right?

The thing is, saying that something is wrong is not a proof of anything: the signal to noise ratio is also important. Every time something happens, everybody knew it was going to happen: the problem is, this is true also for all the things that eventually didn't happen. It's very tempting, after the fact, to say "ah, we all knew it". It's also, mostly, a delusion

Known unknowns etcetera :)

Probably the best image, showing the scale of the collapse: https://gfx.nrk.no/gJothoXlgJysV_sS10u_RQaXLsIZsJIlLIQrfEX8E...

Why did they even build apartments under a bridge or a bridge over apartments? Can't think what would of have happened if the whole bridge collapses.

Same reason they build housing near other highly undesirable locations.

The housing is right next to an industrial trainyard from the looks of it. It was already undesirable before the bridge was built over it.

On the BBC the person they interviewed said that those apartments were abandoned however, so it may not be as bad as it looks.

Not just a trainyard: reportedly the bridge runs above Ansaldo Energia, a big company that makes generators and turbines. So yeah, definitely not prime land, but still crowded.

It's Genoa: sandwiched between sea and mountains, space is at a premium. Think of those lovely shots of Manarola and Cinque Terre, multiply them by a million, add one of Europe's biggest ports, and that's Genoa.

If you're building a tall apartment block you're already trusting your building regulations/safety practices to prevent disaster; having a bridge above you doesn't seem inherently more risky than having n floors of housing above you.

Because most of thr time bridges don’t collapse and it’s nice not to waste the space and create an unpleasant pedestrian dead zone below?

I wonder if they had insurance against the bridge falling?

The precollapse photos make me think that the bridge was built over an existing industrial area with minimal disruption to existing structures.

Looking at some of the links from the various Wikipedia articles on the subject, it does look like the buildings underneath the bridge predate the bridge: http://informesdelaconstruccion.revistas.csic.es/index.php/i...

In this case it is why they built a bridge over existing buildings.

A photo of the construction (1964):

https://www.autostrade.it/comunicazione-e-media/mediateca/ar...

By the same logic people should not live inside buildings other than cabins: if the building itself collapses the inhabitants don't survive.

The assumption is "falling bridges are a black swan event, there's hundreds of more likely corner cases to cover before you get there."

Usually, the bridge is new-ish (second half of 20th century or newer) and the buildings are 19th century or older. https://www.google.com/maps/@50.0651354,14.4307227,3a,75y,22...

And here is an image of what it looked like before: https://www.alamy.com/stock-photo-genoa-liguria-polcevera-mo...

Another "before" image, from roughly the same perspective (from an article someone posted below).

http://cdn-media.ingegneri.info/wp-content/uploads/2016/07/C...

Looks 'spindly'

I know that's an international standards, and in general it's safe and nothing to worry about, but I hate the fact that we build houses under bridges or bridges above houses. Even probable things like a drunk throwing glass bottle to my garden from moving train scare shit out of me.

It's not a prime location, but beats not having enough housing.

What about the Netherlands, with 20% of the population living below sea level, waiting for the day the dike breaks?

We're not waiting, we're currently reinforcing the dikes so they'll be estimated to break only once every 100,000 years instead of every 10,000 years, while taking sea level rise into account.

There's that one dike in Wilnis though that threatens to break every time we have a severe drought, like this year...

I know, I've lived in NL most my life. Must remember Poe's law next time.

> threatens to break every time we have a severe drought

Interesting! Why would a dike be under greater threat in a drought when there is less water?

It dries out, loses volume and weight, then deforms and tears. There was a dike near Wilnis that actually broke in 2003, leading to half a metre of water in some streets there. Maybe the dike that was in the news a few weeks ago (it didn't quite break, but there was some danger) was a different one; I didn't check, but it was also near that village.

https://nl.wikipedia.org/wiki/Kadebreuk_Wilnis

Or someone taking a shit in a train with an old-style toilet...

People committing suicide in Seattle, jumping from the 99 bridge, led to at least one PTSD retirement from Adobe. People seemed not to want to land in the water, but on land, and the Adobe area was apparently an inviting target.

Some homeless guys smoking crack under an overpass ignited nearby material; the resulting fire led to the collapse of a stretch of I-85 in Atlanta last year.

Don't live under a bridge if you can help it. Given the state of disrepair of most American infrastructure it takes very little to bring them down.

That green delivery truck (middle, left side) is really close to the edge of the collapsed section. What a nightmare for a driver of being so close to dying and seeing the entire thing happen (I assume).

There was at least one truck on the collapsed section where the driver survived (albeit with some injuries). Quoted as "I was normally driving, when the road just disappeared and everything started falling."

This tragedy shows the importance of inspection and cost of maintenance of infrastructure. In the U.S. there are approximately 600,000 highway bridges. It's estimated that a quarter of them are at their end-of-life mark (that avg being estimated by some at 70). Not counting over 1,700 bridges still in use built before the 19th century, the breakdown is something like this:

    Decade   No. Built
      1900       6,084
      1910       5,893
      1920      17,883
      1930      42,009
      1940      25,971
      1950      64,085
      1960      99,975
      1970      82,129
      1980      78,279
      1990      81,410
      2000      71,475
      2010      38,038

This is just bridges. There are also about 84,000 dams and in a decade or two a huge number of both of these will approach their end of life, just as a legion of civil engineers go into retirement.

> This tragedy shows the importance of inspection and cost of maintenance of infrastructure.

Your table is scary - and it leads me to one question: why is the future maintenance not budgeted in with any public infrastructure project? For example, a city wants a shiny new bridge... but without provable funding for the maintenance in the future (e.g. tax projections), it is not allowed to be built.

Of course stuff like economic shifts (leading to a loss of tax base) can't be prevented but it's a small risk compared to some politician deciding "I need something monumental where I can cut the opening ribbons" and loading the future generations with maintenance debt.

These are easily the first to get the axe, because we now live in the Uber Tax Cuter Politician.

For me now I vote for the politician that will have the most taxes.

Certain recent presidents promised $1.5 trillion in infrastructure spending but you don't always get what you vote for.

America would rather build a giant wall than fix their crumbling infrastructure, so I don't think there's much cause for optimism in this regard.

You would need every local, state, and federal entity to move to GAAP or IFRS instead of cash basis accounting at the same time. Otherwise some localities would purposefully not do so to claim that they're a tax haven good for attracting jobs. And such a move would probably require a massive correction in taxes or service levels or pensions to get back into shape, which would be a hard lift even for the most authoritarian of governments.

This is, in fact, how greenfield suburbs operate; they claim much lower tax rates because they don't really care about the infrastructure lifecycle, whereas cities are constantly maintaining and fixing things. Some of the first suburbs in America in Nassau County have such poor financial positions that county finances have been controlled by the state since 2000, and property taxes have hiked every year, with increases of up to 20% in a single year. https://en.wikipedia.org/wiki/Nassau_Interim_Finance_Authori...

> but without provable funding for the maintenance in the future (e.g. tax projections), it is not allowed to be built.

Because proving viable funding does nothing to guarantee that those funds will be put towards maintenance, repair, and replacement. The next round of legislators in 10 years may very well decide to put that money elsewhere.

From an article in Le Temps[1], the bridge had some conception issue; Concrete viscosity wasn't consider correctly. The cost of maintenance was very high and a replacement was considered but the project was opposed.

[1] https://www.letemps.ch/monde/catastrophe-genes-lecroulement-...

Yet another bridge design felled by over-reliance on concrete for structural integrity. A lot more bridges are going to fail around the world because they rely too much on concrete, and on dangerous designs without sufficient redundancy.

I like ancient Roman bridges because they're both complex and simple, but my favorite thing about them is how utilitarian they are. At least the examples we have today were clearly not undermining their integrity for the sake of a cool design (2 prestressed concrete tension beams? what the fuck?). Pretty much the only thing that would fell them was the force of flooding rivers. Some fell apart over time, but we're talking over a thousand years. Bridges today barely last 100.

We have to stop letting architects design, and cities then build, hipster bridges. Their primary consideration must be their integrity and longevity.

>We have to stop letting architects design, and cities then build, hipster bridges. Their primary consideration must be their integrity and longevity.

Agreed. You don't have to go back to roman times to see engineering for function over form. If there's one thing the red side of the iron curtain did right it was not letting form compromise function when it came to public works and civil engineering.

>At least the examples we have today were clearly not undermining their integrity for the sake of a cool design

What people like to see follows what they're used to seeing. A good example is the GMT800 Chevy truck platform. In 2000-2005 everyone thought they looked like ugly slant eyed jelly beans, now they just look normal because people have gotten used to them. If we built functional things people would get used to how they look and start to like it.

"If there's one thing the red side of the iron curtain did right it was not letting form compromise function when it came to public works and civil engineering."

Um. You're technically correct (because the reasoning was "form be damned, gotta build a wartime infrastructure, we'll just let civilians use it until it's needed for tanks"), but this was undermined by lack of maintenance.

Whenever there is a bridge failure (or similar, highly-visible civil engineering failure) I recommend to engineers of all stripes that they go read the works of Henry Petroski. In particular:

- To Engineer Is Human: The Role of Failure in Successful Design (1985) [1]

- Design Paradigms: Case Histories of Error and Judgment in Engineering (1994) [2]

and

- Engineers of Dreams: Great Bridge Builders and The Spanning of America (1995) [3]

He also wrote a salient op-ed after the 2007 bridge failure in Minneapolis: Learning from bridge failure. [4]

[1] https://www.amazon.com/dp/0679734163

[2] https://www.amazon.com/dp/0521466490

[3] https://www.amazon.com/dp/0679760210

[4] http://www.latimes.com/la-oe-petroski4aug04-story.html

Article from 2016 talking about the people that designed and built the bridge: http://www.ingegneri.info/news/infrastrutture-e-trasporti/po... (in Italian, Google Translate may help with it).

Its 404ing, did they take it down?

https://web.archive.org/web/20180814113709/www.ingegneri.inf... An old mirror on the waybackmachine

They updated the page with today's news: http://www.ingegneri.info/news/infrastrutture-e-trasporti/po...

on archive.is: http://archive.is/nZ9rF

It's a bit long to translate while typing on a phone, but the main takeaway is that it was build in the sixties with then-novel and not fully understood material engineering practices which then forced frequent and expensive extraordinary repairs, to the point that it would soon have been economical to just demolish and rebuild it.

As for people asking why the highway needs to go through Genova instead of around, it's probably the same kind of reasoning that leads to using nuclear bombs to build harbors and the like.

>As for people asking why the highway needs to go through Genova instead of around,

Mountains. And a few of the major highways actually go under Genoa, via tunnels.

A very small piece of land on the sea with a very steep 1000 meters tall mountain next to it, that's why.

I know, but are you familiar with how terrible it looks, even when it doesn't collapse? Genova hasn't ever been the prettiest city, but still.

People tend to pick an ugly city over hours of traffic jams in a pretty city.

It's more that people in Italy like to live and die close to where they were born. Genoa also was a very busy port until relatively recently, which is a natural population magnet.

It's the biggest port in Italy, and 63rd worldwide. The population increased when the big public industrial complexes were active, now it's declined.

Translation not very clear, but seems to say towards the end that the bridge will quickly cost more than it's worth to maintain (issues with the concrete?) and will need to be demolished.

I'm guessing what happened here is neither maintenance nor (planned) demolition.

Nothing at this scale but this summer in Finland there was a national park bridge fail. The merging of the local municipalities caused the bridge maintenance to be taken care of by the new municipality. In the merge the maintenance was simply forgotten for ten years.

https://yle.fi/uutiset/osasto/news/mondays_papers_tractor_ta...

Part of the collapse - https://www.youtube.com/watch?v=P0c4N91otMs&feature=youtu.be

Coincidentally, a book has just been published on the I-35W bridge collapse, written by one of the survivors. I wonder how many parallels there will be (less a tragedy of design and more a tragedy of maintenance reports gone unheeded for decades). https://www.amazon.com/dp/B077FHMNJX/

As Italian I feel very touched. Hope the body count won't go up. What a tragedy! This is the live streaming from an Italian newspaper https://video.repubblica.it/edizione/genova/genova-crollato-...

I feel you. I think that people all over Europe are sad and shocked. This is heartbreaking for all of us, I was in Genoa not very long ago. I hope that the families get all the help possible.

wow - you can just catch the silhouette of the pier collapsing right at the start of the video amongst the mist. Terrible.

From what I read on Italian forums, Italian engineers say that the materials that were used to build the bridge weren't the same chosen by the designers.

It will be a while before we learn the actual cause for the collapse, however.

>From what I read on Italian forums, Italian engineers say that the materials that were used to build the bridge weren't the same chosen by the designers.

Care to post a link?

The bridge (actually a long viaduct) has been subject to several overhaulings in the years, including the replacement of some structural parts, though these interventions were largely related to the deck, while - at least from the pictures I have seen - it seems more like a pier collapsed, which is "unusual".

There is a live stream from the bridge currently available on youtube:

https://www.youtube.com/watch?v=pBjfUyvtr3w

I don't know if this brigde collapse could be prevented but they could at least not build bridges above buildings. There probably was a better place for the bridge.

Genoa is a very 3D (hilly) city, so they really don’t have a choice.

hn is the one site i come to detox from news (porn).

hopefully for me, i wont see so many news here in the future

Every time I refresh the page the title (count) changes, what a tragedy!

Why is this on HN?

rubenbe31 posted it

Bridges are engineering.

And it's a matter of public safety, collapses like these.

Highly recommend Henry Petroski's book on bridge building https://www.thriftbooks.com/w/to-engineer-is-human-the-role-...

That picture of the Tacoma Narrows' incident on the cover totally grabbed my eyeballs. This book looks super interesting, thank you for the recommendation.

Please allow this article to help you appreciate bridges. :) http://randsinrepose.com/archives/the-makers-of-things/

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