News articles about the ship's collision with the Baltimore Key bridge
have been referring to it as a "Black swan event". I had to look up
that term:

"The black swan theory or theory of black swan events is a metaphor
that describes an event that comes as a surprise, has a major effect,
and is often inappropriately rationalized after the fact with the
benefit of hindsight."

For a more detailed explantion:

https://corporatefinanceinstitute.com/resources/economics/examples-of-black-swan-events/#:~:text=The%20Great%20Recession,been%20a%20booming%20housing%20market.

On 31/03/24 15:00, Tony Cooper wrote:
> News articles about the ship's collision with the Baltimore Key bridge
> have been referring to it as a "Black swan event". I had to look up
> that term:
>
> "The black swan theory or theory of black swan events is a metaphor
> that describes an event that comes as a surprise, has a major effect,
> and is often inappropriately rationalized after the fact with the
> benefit of hindsight."
>
> For a more detailed explantion:
>
> https://corporatefinanceinstitute.com/resources/economics/examples-of-black-swan-events/#:~:text=The%20Great%20Recession,been%20a%20booming%20housing%20market.

Interesting. I suppose the Australian finance people call it a white
swan event.

--
Peter Moylan http://www.pmoylan.org
Newcastle, NSW

Le 31/03/2024 à 06:08, Peter Moylan a écrit :
> On 31/03/24 15:00, Tony Cooper wrote:
>>
>> News articles about the ship's collision with the Baltimore Key bridge
>> have been referring to it as a "Black swan event".  I had to look up
>> that term:
>>
>> "The black swan theory or theory of black swan events is a metaphor
>> that describes an event that comes as a surprise, has a major effect,
>> and is often inappropriately rationalized after the fact with the
>> benefit of hindsight."
>>
>> For a more detailed explantion:
>>
>> https://corporatefinanceinstitute.com/resources/economics/examples-of-black-swan-events/#:~:text=The%20Great%20Recession,been%20a%20booming%20housing%20market.
>
> Interesting. I suppose the Australian finance people call it a white
> swan event.

A few days ago, a chap on France Info - Michel Virlogeux, designer of
the Pont de Normandie - was saying that this kind of accident is bound
to happen, and that bridge design should take that into account.

Let me search a bit - yes, here it is - 26th March:

« Alors évidemment, ce n'est pas tous les jours, mais c'est un type
d'accident qui est relativement classique. Le pont de Normandie que j'ai
construit a été conçu pour se mettre à l'abri de ce genre de chose en
mettant les piles en dehors de la rivière. Vous avez un pylône qui est
sur la rive gauche, à terre, un pylône vers la rive droite, le long de
la digue, protégé par une enceinte de protection pour le cas où des
bateaux s'écarteraient très largement du chenal de navigation » -
<https://www.francetvinfo.fr/monde/usa/pont-de-baltimore-effondre-il-n-y-a-aucune-chance-qu-une-pile-de-pont-puisse-resister-a-un-tel-choc-selon-le-concepteur-du-pont-de-normandie_6448750.html>

So just bad design, then. An accident waiting to happen.

Hibou wrote:

>> Interesting. I suppose the Australian finance people call it a white
>> swan event.
>
> A few days ago, a chap on France Info - Michel Virlogeux, designer of
> the Pont de Normandie - was saying that this kind of accident is bound
> to happen, and that bridge design should take that into account.

Danish bridge builders do take it into account. I - and probably many
other people - was surprised how quickly and easily the bridge
collapsed. In Denmark the ship would have hit a solid concrete block
below the water line which would have taken most of the impact.

--
Bertel, Denmark

On 31/03/24 17:00, Hibou wrote:
> Le 31/03/2024 à 06:08, Peter Moylan a écrit :
>> On 31/03/24 15:00, Tony Cooper wrote:
>>>
>>> News articles about the ship's collision with the Baltimore Key
>>> bridge have been referring to it as a "Black swan event". I had
>>> to look up that term:
>>>
>>> "The black swan theory or theory of black swan events is a
>>> metaphor that describes an event that comes as a surprise, has a
>>> major effect, and is often inappropriately rationalized after the
>>> fact with the benefit of hindsight."
>>>
>>> For a more detailed explantion:
>>>
>>> https://corporatefinanceinstitute.com/resources/economics/examples-of-black-swan-events/#:~:text=The%20Great%20Recession,been%20a%20booming%20housing%20market.
>>>
>>>
>>
>> Interesting. I suppose the Australian finance people call it a
>> white swan event.
>
> A few days ago, a chap on France Info - Michel Virlogeux, designer of
> the Pont de Normandie - was saying that this kind of accident is
> bound to happen, and that bridge design should take that into
> account.
>
> Let me search a bit - yes, here it is - 26th March:
>
> « Alors évidemment, ce n'est pas tous les jours, mais c'est un type
> d'accident qui est relativement classique. Le pont de Normandie que
> j'ai construit a été conçu pour se mettre à l'abri de ce genre de
> chose en mettant les piles en dehors de la rivière. Vous avez un
> pylône qui est sur la rive gauche, à terre, un pylône vers la rive
> droite, le long de la digue, protégé par une enceinte de protection
> pour le cas où des bateaux s'écarteraient très largement du chenal de
> navigation » -
> <https://www.francetvinfo.fr/monde/usa/pont-de-baltimore-effondre-il-n-y-a-aucune-chance-qu-une-pile-de-pont-puisse-resister-a-un-tel-choc-selon-le-concepteur-du-pont-de-normandie_6448750.html>
>
> So just bad design, then. An accident waiting to happen.

It happened in Hobart in 1975, and again a section of the bridge was
taken out by a bulk carrier. Twelve people died. Like the Baltimore
bridge, it's a bridge with pylons in the water. Unlike the Baltimore
bridge, there was no domino effect.

--
Peter Moylan http://www.pmoylan.org
Newcastle, NSW

Le 31/03/2024 à 07:00, Hibou a écrit :
>
> A few days ago, a chap on France Info - Michel Virlogeux, designer of
> the Pont de Normandie - was saying that this kind of accident is bound
> to happen, and that bridge design should take that into account.
>
> Let me search a bit - yes, here it is - 26th March:
>
> « Alors évidemment, ce n'est pas tous les jours, mais c'est un type
> d'accident qui est relativement classique. Le pont de Normandie que j'ai
> construit a été conçu pour se mettre à l'abri de ce genre de chose en
> mettant les piles en dehors de la rivière. Vous avez un pylône qui est
> sur la rive gauche, à terre, un pylône vers la rive droite, le long de
> la digue, protégé par une enceinte de protection pour le cas où des
> bateaux s'écarteraient très largement du chenal de navigation » -
> <https://www.francetvinfo.fr/monde/usa/pont-de-baltimore-effondre-il-n-y-a-aucune-chance-qu-une-pile-de-pont-puisse-resister-a-un-tel-choc-selon-le-concepteur-du-pont-de-normandie_6448750.html>

I have a few minutes, and I should really supply a summary...

It's not an everyday accident, but it is quite classic. The Bridge of
Normandy that I built was designed to withstand this sort of thing, with
towers outside the [main part of the] river [it's a cable-stayed
bridge]. One is on the left bank, the other close to the right bank and
protected by [reinforced concrete]¹ in case ships stray well outside the
navigation channel.

¹Source (I'm not going to translate this): « Mais des bateaux de 130 000
tonnes et de douze mètres de tirant d'eau, arrivant avec une vitesse et
un angle d'incidence déduits de simulations d'incidents établies par la
SOGREAH, pourraient venir frapper violemment ses fondations. Jean Armand
Calgaro a donc imagine de constituer une enceinte de protection autour
de ces fondations, formée par une longrine en béton arme de grandes
dimensions (4 mètres de largeur sur 5 de hauteur) fondée sur une série
de pieux rapproches de gros diamètre (pieux de 2,60 mètre de diamètre
espaces de 9 mètres), dessinant un demi cercle autour de la fondation de
chaque fût » -
<https://www.e-periodica.ch/cntmng?pid=bse-cr-001:1988:13::1054>

> So just bad design, then. An accident waiting to happen.

On 31-Mar-24 7:00, Hibou wrote:
> Le 31/03/2024 à 06:08, Peter Moylan a écrit :
>> On 31/03/24 15:00, Tony Cooper wrote:
>>>
>>> News articles about the ship's collision with the Baltimore Key bridge
>>> have been referring to it as a "Black swan event".  I had to look up
>>> that term:
>>>
>>> "The black swan theory or theory of black swan events is a metaphor
>>> that describes an event that comes as a surprise, has a major effect,
>>> and is often inappropriately rationalized after the fact with the
>>> benefit of hindsight."
>>>
>>> For a more detailed explantion:
>>>
>>> https://corporatefinanceinstitute.com/resources/economics/examples-of-black-swan-events/#:~:text=The%20Great%20Recession,been%20a%20booming%20housing%20market.
>>
>> Interesting. I suppose the Australian finance people call it a white
>> swan event.
>
> A few days ago, a chap on France Info - Michel Virlogeux, designer of
> the Pont de Normandie - was saying that this kind of accident is bound
> to happen, and that bridge design should take that into account.
>
> Let me search a bit - yes, here it is - 26th March:
>
> « Alors évidemment, ce n'est pas tous les jours, mais c'est un type
> d'accident qui est relativement classique. Le pont de Normandie que j'ai
> construit a été conçu pour se mettre à l'abri de ce genre de chose en
> mettant les piles en dehors de la rivière. Vous avez un pylône qui est
> sur la rive gauche, à terre, un pylône vers la rive droite, le long de
> la digue, protégé par une enceinte de protection pour le cas où des
> bateaux s'écarteraient très largement du chenal de navigation » -
> <https://www.francetvinfo.fr/monde/usa/pont-de-baltimore-effondre-il-n-y-a-aucune-chance-qu-une-pile-de-pont-puisse-resister-a-un-tel-choc-selon-le-concepteur-du-pont-de-normandie_6448750.html>
>
> So just bad design, then. An accident waiting to happen.
>
I'm sure the investigation will find that:
At least one engineer involved in either the construction or maintenance
of the bridge had raised exactly this potential problem[1].

Also that there was some national level advisory publication which
recommended that all bridges, in this type of location, should be
reviewed to determine how vulnerable they were.

[1] Raised, but it may or may not have been formally recorded.

--
Sam Plusnet

On 31/03/2024 5:00 p.m., Tony Cooper wrote:
> News articles about the ship's collision with the Baltimore Key bridge
> have been referring to it as a "Black swan event". I had to look up
> that term:
>
> "The black swan theory or theory of black swan events is a metaphor
> that describes an event that comes as a surprise, has a major effect,
> and is often inappropriately rationalized after the fact with the
> benefit of hindsight."
>
> For a more detailed explantion:
>
> https://corporatefinanceinstitute.com/resources/economics/examples-of-black-swan-events/#:~:text=The%20Great%20Recession,been%20a%20booming%20housing%20market.
>
>

OED:
black swan (proverbial) something extremely rare (or non-existent); a
rarity, _rara avis_.
(examples from late 1500s)

On 31/03/2024 7:00 p.m., Hibou wrote:
> Le 31/03/2024 à 06:08, Peter Moylan a écrit :
>> On 31/03/24 15:00, Tony Cooper wrote:
>>>
>>> News articles about the ship's collision with the Baltimore Key bridge
>>> have been referring to it as a "Black swan event".  I had to look up
>>> that term:
>>>
>>> "The black swan theory or theory of black swan events is a metaphor
>>> that describes an event that comes as a surprise, has a major effect,
>>> and is often inappropriately rationalized after the fact with the
>>> benefit of hindsight."
>>>
>>> For a more detailed explantion:
>>>
>>> https://corporatefinanceinstitute.com/resources/economics/examples-of-black-swan-events/#:~:text=The%20Great%20Recession,been%20a%20booming%20housing%20market.
>>>
>>
>> Interesting. I suppose the Australian finance people call it a white
>> swan event.
>
> A few days ago, a chap on France Info - Michel Virlogeux, designer of
> the Pont de Normandie - was saying that this kind of accident is bound
> to happen, and that bridge design should take that into account.
>
> Let me search a bit - yes, here it is - 26th March:
>
> « Alors évidemment, ce n'est pas tous les jours, mais c'est un type
> d'accident qui est relativement classique. Le pont de Normandie que j'ai
> construit a été conçu pour se mettre à l'abri de ce genre de chose en
> mettant les piles en dehors de la rivière. Vous avez un pylône qui est
> sur la rive gauche, à terre, un pylône vers la rive droite, le long de
> la digue, protégé par une enceinte de protection pour le cas où des
> bateaux s'écarteraient très largement du chenal de navigation » -
> <https://www.francetvinfo.fr/monde/usa/pont-de-baltimore-effondre-il-n-y-a-aucune-chance-qu-une-pile-de-pont-puisse-resister-a-un-tel-choc-selon-le-concepteur-du-pont-de-normandie_6448750.html>
>
>
> So just bad design, then. An accident waiting to happen.
>

Within hours of the event, looking around for information, I saw a clip
of a civil engineer from New Jersey being interviewed, explaining that,
yes, there were ways to protect a bridge against this sort of accident,
and describing a "fendering structure" (I think those were his words)
which would absorb much of the impact.
So everybody knew.

On Sun, 31 Mar 2024 00:00:53 -0400, Tony Cooper
<tonycooper214@gmail.com> wrote:

>News articles about the ship's collision with the Baltimore Key bridge
>have been referring to it as a "Black swan event". I had to look up
>that term:
>
>"The black swan theory or theory of black swan events is a metaphor
>that describes an event that comes as a surprise, has a major effect,
>and is often inappropriately rationalized after the fact with the
>benefit of hindsight."
>
>For a more detailed explantion:
>
>https://corporatefinanceinstitute.com/resources/economics/examples-of-black-swan-events/#:~:text=The%20Great%20Recession,been%20a%20booming%20housing%20market.
>

The metaphor might be a bit familiar because there was a
book by that name, 2007.
The Black Swan: The Impact of the Highly Improbable is a 2007 book
by Nassim Nicholas Taleb, who is a former options trader. The book
focuses on the extreme impact of rare and unpredictable outlier
events—and the human tendency to find simplistic explanations for
these events, retrospectively. Wikipedia

I read the book back then, or else I read a long discussion of it.

--
Rich Ulrich

On Sun, 31 Mar 2024 08:12:49 +0200, Bertel Lund Hansen
<gadekryds@lundhansen.dk> wrote:

>Hibou wrote:
>
>>> Interesting. I suppose the Australian finance people call it a white
>>> swan event.
>>
>> A few days ago, a chap on France Info - Michel Virlogeux, designer of
>> the Pont de Normandie - was saying that this kind of accident is bound
>> to happen, and that bridge design should take that into account.
>
>Danish bridge builders do take it into account. I - and probably many
>other people - was surprised how quickly and easily the bridge
>collapsed. In Denmark the ship would have hit a solid concrete block
>below the water line which would have taken most of the impact.

U.S. regulations from the 1980s require fenders. That bridge
was built in the 1970s.

We apparently have a big number of older bridges. A news
show flashed the number '2600' or '4600' as the number of
similar bridges listed at a government source, and only 36% of
them (they said) had piers that were protected.

But they did not say how much they were protected, and
the bridge that went down had been listed as 'protected'.

--
Rich Ulrich

In article <uub04u$1iajq$1@dont-email.me>,
Peter Moylan <peter@pmoylan.org.invalid> wrote:

>It happened in Hobart in 1975, and again a section of the bridge was
>taken out by a bulk carrier. Twelve people died. Like the Baltimore
>bridge, it's a bridge with pylons in the water. Unlike the Baltimore
>bridge, there was no domino effect.

It's worth noting that container ships are many times bigger now than
they were in the late 1960s when the Key Bridge was designed, which
means among other things that they're much closer to the edges of the
navigation channel.

I expect that a replscement bridge will be constructed with piers
farther from the channel, such that a ship large enough to damage a
pier would run aground before striking it. The clear span of the old
bridge is not so large; a replacement could theoretically be
constructed without putting any piers in the water, if the geology
allows.

I noted elsewhere that for most of the 20th century, American civil
engineers were prejudiced against cable-stayed bridges, which were
common in Europe during the post-WW2 reconstruction due to their
economy of construction. This didn't start to shift until the late
1980s.

-GAWollman

--
Garrett A. Wollman | "Act to avoid constraining the future; if you can,
wollman@bimajority.org| act to remove constraint from the future. This is
Opinions not shared by| a thing you can do, are able to do, to do together."
my employers. | - Graydon Saunders, _A Succession of Bad Days_ (2015)

Le 31/03/2024 à 23:40, Garrett Wollman a écrit :
> In article <uub04u$1iajq$1@dont-email.me>,
> Peter Moylan <peter@pmoylan.org.invalid> wrote:
>>
>> It happened in Hobart in 1975, and again a section of the bridge was
>> taken out by a bulk carrier. Twelve people died. Like the Baltimore
>> bridge, it's a bridge with pylons in the water. Unlike the Baltimore
>> bridge, there was no domino effect.
>
> It's worth noting that container ships are many times bigger now than
> they were in the late 1960s when the Key Bridge was designed, which
> means among other things that they're much closer to the edges of the
> navigation channel.

Noted.

> I expect that a replscement bridge will be constructed with piers
> farther from the channel, such that a ship large enough to damage a
> pier would run aground before striking it. The clear span of the old
> bridge is not so large; a replacement could theoretically be
> constructed without putting any piers in the water, if the geology
> allows.
>
> I noted elsewhere that for most of the 20th century, American civil
> engineers were prejudiced against cable-stayed bridges, which were
> common in Europe during the post-WW2 reconstruction due to their
> economy of construction. This didn't start to shift until the late
> 1980s.

Galloping Gertie! one might say.

In article <uudj7n$2b3sn$1@dont-email.me>,
Hibou <vpaereru-unmonitored@yahoo.com.invalid> wrote:
>Le 31/03/2024 à 23:40, Garrett Wollman a écrit :
>> I noted elsewhere that for most of the 20th century, American civil
>> engineers were prejudiced against cable-stayed bridges, which were
>> common in Europe during the post-WW2 reconstruction due to their
>> economy of construction. This didn't start to shift until the late
>> 1980s.
>
>Galloping Gertie! one might say.

The Tacoma Narrows Bridge was a suspension bridge, of course, and not
a cable-stayed bridge.

-GAWollman

--
Garrett A. Wollman | "Act to avoid constraining the future; if you can,
wollman@bimajority.org| act to remove constraint from the future. This is
Opinions not shared by| a thing you can do, are able to do, to do together."
my employers. | - Graydon Saunders, _A Succession of Bad Days_ (2015)

On 2024-04-01 15:24:53 +0000, Garrett Wollman said:

> In article <uudj7n$2b3sn$1@dont-email.me>,
> Hibou <vpaereru-unmonitored@yahoo.com.invalid> wrote:
>> Le 31/03/2024 à 23:40, Garrett Wollman a écrit :
>>> I noted elsewhere that for most of the 20th century, American civil
>>> engineers were prejudiced against cable-stayed bridges, which were
>>> common in Europe during the post-WW2 reconstruction due to their
>>> economy of construction. This didn't start to shift until the late
>>> 1980s.
>>
>> Galloping Gertie! one might say.
>
> The Tacoma Narrows Bridge was a suspension bridge, of course, and not
> a cable-stayed bridge.

At one time that was the film I'd seen for the largest number of times.

--
Athel -- French and British, living in Marseilles for 37 years; mainly
in England until 1987.

In article <uuejk5$du7$1@usenet.csail.mit.edu>,
Garrett Wollman <wollman@hergotha.csail.mit.edu> wrote:
> In article <uudj7n$2b3sn$1@dont-email.me>,
> Hibou <vpaereru-unmonitored@yahoo.com.invalid> wrote:
> >Le 31/03/2024 à 23:40, Garrett Wollman a écrit :
> >> I noted elsewhere that for most of the 20th century, American civil
> >> engineers were prejudiced against cable-stayed bridges, which were
> >> common in Europe during the post-WW2 reconstruction due to their
> >> economy of construction. This didn't start to shift until the late
> >> 1980s.
> >
> >Galloping Gertie! one might say.

> The Tacoma Narrows Bridge was a suspension bridge, of course, and not
> a cable-stayed bridge.

we were shown the film of it during my Engineering degree, (1959-62)

--
from KT24 in Surrey, England - sent from my RISC OS 4té²
"I'd rather die of exhaustion than die of boredom" Thomas Carlyle

Athel Cornish-Bowden wrote:

> On 2024-04-01 15:24:53 +0000, Garrett Wollman said:

>> In article <uudj7n$2b3sn$1@dont-email.me>,
>> Hibou <vpaereru-unmonitored@yahoo.com.invalid> wrote:
...

>>> Galloping Gertie! one might say.
>>
>> The Tacoma Narrows Bridge was a suspension bridge, of course, and not
>> a cable-stayed bridge.

> At one time that was the film I'd seen for the largest number of times.

It's certainly mine. I show it to my students every year.

--
Jerry Friedman

After serious thinking charles wrote :
> In article <uuejk5$du7$1@usenet.csail.mit.edu>,
> Garrett Wollman <wollman@hergotha.csail.mit.edu> wrote:
>> In article <uudj7n$2b3sn$1@dont-email.me>,
>> Hibou <vpaereru-unmonitored@yahoo.com.invalid> wrote:
>>> Le 31/03/2024 à 23:40, Garrett Wollman a écrit :
>>>> I noted elsewhere that for most of the 20th century, American civil
>>>> engineers were prejudiced against cable-stayed bridges, which were
>>>> common in Europe during the post-WW2 reconstruction due to their
>>>> economy of construction. This didn't start to shift until the late
>>>> 1980s.
>>>
>>> Galloping Gertie! one might say.
>
>> The Tacoma Narrows Bridge was a suspension bridge, of course, and not
>> a cable-stayed bridge.
>
> we were shown the film of it during my Engineering degree, (1959-62)

ISTR that the explanation of the resonance was, perhaps, oversimplified
in most presentations. Being a bit banger, I didn't retain the full
scope of the correction.

/dps

--
"I'm glad unicorns don't ever need upgrades."
"We are as up as it is possible to get graded!"
_Phoebe and Her Unicorn_, 2016.05.15

Le 01/04/2024 à 17:08, charles a écrit :
>
> we were shown the film of it during my Engineering degree, (1959-62)

There seem to be a lot of engineers in this forum.

Good chaps, engineers. The profession is one of the more honest. One can
fool people a lot of the time, but one can't fool Nature.

On 2024-04-02 08:15:57 +0000, Hibou said:

> Le 01/04/2024 à 17:08, charles a écrit :
>>
>> we were shown the film of it during my Engineering degree, (1959-62)
>
> There seem to be a lot of engineers in this forum.
>
> Good chaps, engineers. The profession is one of the more honest. One
> can fool people a lot of the time, but one can't fool Nature.

Maybe, but the chaps who built the bridge in Baltimore thought they could.

--
Athel -- French and British, living in Marseilles for 37 years; mainly
in England until 1987.

On 2024-04-01, jerryfriedman wrote:

> Athel Cornish-Bowden wrote:
>
>> On 2024-04-01 15:24:53 +0000, Garrett Wollman said:
>
>>> In article <uudj7n$2b3sn$1@dont-email.me>,
>>> Hibou <vpaereru-unmonitored@yahoo.com.invalid> wrote:
> ..
>
>>>> Galloping Gertie! one might say.
>>>
>>> The Tacoma Narrows Bridge was a suspension bridge, of course, and not
>>> a cable-stayed bridge.
>
>> At one time that was the film I'd seen for the largest number of times.
>
> It's certainly mine. I show it to my students every year.

I've seen it more than once, but I definitely remember seeing it in a
calculus class.

--
Radiation! Yes, indeed. You hear the most outrageous lies about
it. Half-baked goggle-box do-gooders telling everybody it's bad
for you. Pernicious nonsense! ---J Frank Parnell

In article <uugert$33gcv$1@dont-email.me>,
Hibou <vpaereru-unmonitored@yahoo.com.invalid> wrote:
> Le 01/04/2024 à 17:08, charles a écrit :
> >
> > we were shown the film of it during my Engineering degree, (1959-62)

> There seem to be a lot of engineers in this forum.

> Good chaps, engineers. The profession is one of the more honest. One can
> fool people a lot of the time, but one can't fool Nature.

we were also told that when concrete was first used as a structural
product. all the experimental data showed it was equal in compression and
tension. Funnily enough, the early bridges fell down ;-(

--
from KT24 in Surrey, England - sent from my RISC OS 4té²
"I'd rather die of exhaustion than die of boredom" Thomas Carlyle

On 2024-04-02 10:00:03 +0000, charles said:

> In article <uugert$33gcv$1@dont-email.me>,
> Hibou <vpaereru-unmonitored@yahoo.com.invalid> wrote:
>> Le 01/04/2024 à 17:08, charles a écrit :
>>>
>>> we were shown the film of it during my Engineering degree, (1959-62)
>
>> There seem to be a lot of engineers in this forum.
>
>> Good chaps, engineers. The profession is one of the more honest. One can
>> fool people a lot of the time, but one can't fool Nature.
>
> we were also told that when concrete was first used as a structural
> product. all the experimental data showed it was equal in compression and
> tension. Funnily enough, the early bridges fell down ;-(

Not the ones built by the Romans! The viaduct in Segovia is in almost
as good condition today as it was 2000 years ago.

--
Athel -- French and British, living in Marseilles for 37 years; mainly
in England until 1987.

Ross Clark <benlizro@ihug.co.nz> wrote or quoted:
>black swan (proverbial) something extremely rare (or non-existent)

Existence can be proven epistemically, by observation,
non-existance cannot be proven by non-observation.

There is a Wikipedia article "Observable universe" saying that
we well never be able to observe certain parts of the universe.
Whatever it is that we have never seen, it might be there!
Speaking swans? Swans that can shoot arrows from their mouths?
Speaking swans that can shoot arrows from their mouths?

In article <l7249cFlm7pU1@mid.individual.net>, Athel Cornish-Bowden
<me@yahoo.com> wrote:
> On 2024-04-02 10:00:03 +0000, charles said:

> > In article <uugert$33gcv$1@dont-email.me>, Hibou
> > <vpaereru-unmonitored@yahoo.com.invalid> wrote:
> >> Le 01/04/2024 à 17:08, charles a écrit :
> >>>
> >>> we were shown the film of it during my Engineering degree, (1959-62)
> >
> >> There seem to be a lot of engineers in this forum.
> >
> >> Good chaps, engineers. The profession is one of the more honest. One
> >> can fool people a lot of the time, but one can't fool Nature.
> >
> > we were also told that when concrete was first used as a structural
> > product. all the experimental data showed it was equal in compression
> > and tension. Funnily enough, the early bridges fell down ;-(

> Not the ones built by the Romans! The viaduct in Segovia is in almost as
> good condition today as it was 2000 years ago.

according to Wiki that viaduct is made of unmortared granite blocks - not
concrete.
> --

--
from KT24 in Surrey, England - sent from my RISC OS 4té²
"I'd rather die of exhaustion than die of boredom" Thomas Carlyle