[HN Gopher] How are Rome's monuments still standing?
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How are Rome's monuments still standing?
Author : clouddrover
Score : 52 points
Date : 2021-12-20 03:42 UTC (19 hours ago)
(HTM) web link (www.bbc.com)
(TXT) w3m dump (www.bbc.com)
| KSS42 wrote:
| Here's some great videos on this question from YouTuber
| ToldinStone - Garret Ryan
|
| Author of Naked Statues, Fat Gladiators and War Elephants
|
| Why was Roman concrete forgotten during the Middle Ages?
|
| https://youtu.be/dbvvlFHCNn4
|
| See also his YouTube series: History of Rome in 15 Buildings
|
| The Colosseum: https://youtu.be/m6iHR8zqbiM
| thinkski wrote:
| Does make me wonder what we're building today that will last. I
| suppose the engineers who worked on Voyager or Pathfinder have
| the best shot of having built something enduring.
| rurp wrote:
| Tangentially related to this, one of my hobbies is to explore old
| long abandoned ghost towns and mining camps in the Southwest US.
| It is really impressive how well many of these structures have
| held up in harsh climates. One of my favorite parts is seeing how
| repairs were improvised in the wilderness using whatever supplies
| happened to be available.
|
| The standard approach to trash back then was to throw it in a
| pile nearby. Picking through those dumps can be really
| fascinating and a surprising amount of items are still in good
| shape. A simple heuristic for how old a glass bottle is is how
| thick it is. A modern beer bottle looks paper thin compared to
| one a century old.
|
| Looking at old structures and tools really makes vivid how
| disposable many modern items are.
| hnplj wrote:
| roca wrote:
| Did the Romans really know that using certain volcanic rocks
| would make their concrete structures last longer? Or did they
| mostly just use whatever aggregate was convenient and the
| structures that have survived are the ones that used the right
| rocks? The latter sounds more plausible to me.
|
| Of course we can still learn valuable lessons from these
| surviving structures.
| WalterBright wrote:
| Rome lasted for many centuries, so I imagine they were familiar
| with what worked and what didn't.
| SQueeeeeL wrote:
| Jonathan Blow makes a bunch of great points about our
| simplified view of ancient people, versus the reality of
| their complex achievements which could only be brought about
| by lots of ingenuity and iterations.
|
| https://youtu.be/pW-SOdj4Kkk
| bcrosby95 wrote:
| The interconnectedness of the bronze age was amazing. To
| make bronze required combining metals sourced from
| thousands of miles away from eachother.
|
| In comparison, iron could be made basically anywhere.
| simonebrunozzi wrote:
| TL;DR: their concrete was different.
|
| > Roman concrete, on the other hand, is a simpler mix of
| quicklime made from baking and crushing limestone rocks and, most
| importantly, volcanic rock aggregates of various types, which
| were abundant in the region surrounding Rome. In contrast to the
| aggregates used in modern concrete, these volcanic materials used
| by the Romans are highly reactive and the resulting concrete
| remains chemically active for centuries after it first hardens.
|
| By the way, I don't buy this entirely. Let me tell you why.
|
| The Pantheon is mostly stones and bricks, and "some" concrete to
| keep the bricks together. These large stones are held together by
| simple force of gravity, very much like the Pyramids in Egypt
| (~4,000 years old, or double the age of the Colosseum or the
| Pantheon).
|
| I'm not a materials engineer (just a software engineer). Can
| someone with more knowledge comment on my view?
| ardit33 wrote:
| It is both..... so both the author and you are correct.
|
| Modern concrete has rebar, which eventually gets rusted, and
| corroded, and fails (in 150-200 years). Also, roman concrete
| was just thicker/used more material.
|
| Also simple stone survives forever, while brick a bit less, and
| 'simpler mud bricks' and wood a lot less.
|
| SO, from Roman times, really only the strongest buildings
| survived, and everything else is gone. So, there is a survivor
| bias. We are only looking at the strongest buildings, and not
| the average one.
| mrkstu wrote:
| And as their wealth was staggering, they could afford to
| build 'strong' more than most ancient civilizations and most
| of the conquerors just were assimilated rather than wanting
| to tear it down to the dirt.
| valarauko wrote:
| The Romans weren't any more significantly wealthier than
| other contemporary Old World civilizations/empires - China,
| Persia, or India, for example. Conquerors being assimilated
| is a common theme that runs across most of these
| civilizations as well. However, monumental buildings that
| survive invading armies just tend to be
| dismantled/repurposed by the locals for the building
| material over time. I suspect that part of the reason for
| Roman monuments surviving is that the fall of Western Rome
| lead to an overall decrease in the urban population &
| subsequent demand for building materials. China, India, &
| Persia likely saw no such population decreases.
| _carbyau_ wrote:
| Using survivor bias to our benefit though. Evolution for
| buildings as it were.
|
| While the article title is a blanket question on ALL Roman
| monuments - which clearly didn't all survive - the article is
| about people investigating how the long lasting ones do what
| they do.
|
| Which sounds great to me.
| 8ytecoder wrote:
| I think we're missing another key factor here. Most "well
| preserved" buildings are ones that are in continuous use. So
| they get maintained and repaired. A temple in south India is
| about a 1000 years old. It has seen repeated damages - some
| intentional during conquests - but survives to this day because
| the damages were patched up within a few decades. The "few
| decades" it can go - even with damages - is likely from the
| material and construction. But the centuries that add up comes
| from regular maintenance.
| valarauko wrote:
| Well, while this is true, there is some level of survivorship
| bias here. Plenty of comparable South Indian temples were
| torn down, and the ones that survive are mostly quirks of
| chance. Even the ones that do survive have seen many of their
| gopurams (monumental gates) collapse after a few centuries
| due to political apathy in modern times - the one I recall
| most recently was at Srikalahasti.
| soperj wrote:
| Some structures were build without any concrete at all. That
| being said, they've build sea walls that have lasted thousands
| of years.
| FredPret wrote:
| We use reinforced concrete, concrete with steel bars inside.
| This allows us to built really thin and strong concrete
| bridges, balconies, roofs, etc.
|
| But the steel rusts after a couple of decades.
|
| Rusted steel is marginally larger than new steel.
|
| So when the steel bars expand by rusting, it pushes against the
| concrete from the inside, causing cracks. Then lots of water
| can get in it rusts faster.
|
| Eventually chunks of concrete fall off and structural collapse
| follows.
|
| If we built like the Romans, it would be more expensive, but
| would last 1k+ years.
| WalterBright wrote:
| It's critical to protect the concrete from water.
| smegger001 wrote:
| I wonder how long carbon fiber rebar, or plastic coated steel
| rebar would last.
| Cerium wrote:
| Plastic coated rebar is a product. In theory it can solve
| the rusting problem, but in practice the coating will get
| some nicks during installation that can concentrate
| corrosion leading to point weaknesses. There are additional
| concerns with the bonding between the concrete and the
| coated bar.
| tastyfreeze wrote:
| Basalt rebar is chemically resistant and doesn't corrode.
| It does have a lower tensile strength than carbon fiber but
| is suitable for current designs.
| mc32 wrote:
| There are stainless steel rebar and epoxy coated rebar for
| structures exposed to the elements. Stainless steel rebar
| appears to be kind of expensive so its use is limited.
| dr_orpheus wrote:
| I don't know how it compares to actual rebar reinforced
| concrete, but we do use fiberglass reinforced concrete.
| FredPret wrote:
| Interesting idea, but carbon fiber would need to be really
| cheap. Would work well until a critter of some sort evolves
| that eats plastic
| microtherion wrote:
| The explanation in the article is fascinating, but I wonder how
| much the Romans knew about the durability of their concrete at
| the time, and to what extent they just got lucky by the mix of
| material that happened to be available in their area.
| SQueeeeeL wrote:
| I feel like a single human could trial and error their way to
| a very good paper airplane over the course of 2 or 3 days. It
| seems pretty obvious that a large group of people would trial
| and error products in much the same way, especially those so
| essential to their civilization. Especially with the large
| trade networks that we know to exist back then.
| [deleted]
| hujni wrote:
| I've wondered if maybe the "stones" of the Pyramids were
| poured. It wouldn't surprise me given the lack of gaps.
| tastyfreeze wrote:
| You aren't the only one.
|
| https://youtu.be/znQk_yBHre4
| kmonsen wrote:
| Are there strong counterpoints to this? If that is possible
| it seems extremely more likely than aliens or whatever else
| people are coming up with.
| orwin wrote:
| You're right to not buy this entirely. Roman concrete was great
| because it could harden while in water. And waterworks was
| probably the primary reason why Rome was such an early
| superpower (for multiple reasons: hygiene, stronger ports and
| also mechanical force, as "free" energy give you productivity
| increases. But it had less tensile strength than our current
| concrete.
|
| The reason why multiple structures still hold today and will
| hold longer than most of our structures is more simple than
| that: they over-engineered the shit of everything that still
| hold today. Also for the same reasons, multiple bridges,
| castles, church or structures built between the low medieval
| era and high med/renaissance will likely last as much as roman
| structures did.
| atdrummond wrote:
| They're not. The Romans built a huge amount and much of their
| artistic architectural works remaining today were purposely
| preserved, even if reused for some alternative purpose.
|
| Yes, there are some construction techniques they used that
| contributed to better survival rates than some other structure
| types. But mostly we've ended up with what was lucky enough to
| survive. Replay the historical tape again and we might be
| surprised by what didn't survive war, fires, other natural
| disasters on the second go round.
| cblconfederate wrote:
| > for the same reasons we preserve Victorian era buildings.
|
| Not really, christians destroyed a huge amount and ruthlessly,
| and tons of marble was 'repurposed'. The best chance of a
| building to survive was being used as a church
| atdrummond wrote:
| I suppose I just don't find that substantially different than
| the National Trust repurposing say Ickworth into a hotel. I
| understand that contemporary society places a higher value on
| a certain type of "accurate" preservation than many societies
| that came before but if people had truly wanted historical
| Roman buildings gone, they would be.
| cblconfederate wrote:
| tons of pagan roman and greek statues were destroyed.
| what's left today is only a tiny amount
| atdrummond wrote:
| I agree? My original reply's point was we have a very
| small minority of what the empire constructed. And much
| of that is because it was purposely preserved, if for
| alternative reasons.
| sandgiant wrote:
| Destroying symbols of a previous rule was (is) commons
| practice. Constantine realized that some building and
| monuments were worth preserving and repurposed them as
| "Christian", thereby ensuring their preservation for
| hundreds, or even a thousand of years.
| Pigalowda wrote:
| I recently found out about this sad column repurposed in 608
| AD as an honor to the Eastern Roman Emperor, Phocas.
|
| https://en.m.wikipedia.org/wiki/Column_of_Phocas
|
| The city had been sacked multiple times at that point and I
| suppose it was the best they could do.
| atdrummond wrote:
| What's crazy there is that by the mid-1800s, sketches would
| only show a portion of the column due to the rise in ground
| level over the intermediate period.
| peoplefromibiza wrote:
| Nope.
|
| Romans invented concrete, and it was so good that still today
| the average concrete can't compete with it (its resistance to
| cracks is one example)
|
| Rewind history and roman buildings would still be there.
|
| They are thought to be one of the few things that would survive
| human extinction.
|
| The only thing that would outlast them are Giza Pyramids.
|
| https://en.m.wikipedia.org/wiki/Roman_concrete
| dehrmann wrote:
| There might be some truth to Roman concrete still being
| reactive leading to its longevity, but I'd be really careful
| about dismissing survivorship bias.
| atdrummond wrote:
| I don't have the energy to revisit the arguments about Roman
| concrete that come up every time it is mentioned on HN.
| Needless to say, the notion that their "superior" method was
| "forgotten" is a massive oversimplification of what actually
| happened.
|
| Another comment made my point better than I did - which was
| that Roman buildings that remained standing did so because
| they were useful for some purpose, often an alternative one
| (such as a church). It speaks to their value specifically as
| architecture and is mostly orthogonal to their construction
| techniques. There are plenty of old buildings (such as Horyu-
| ji, Ruwanweli Maha Seya, Mousa Broch, etc) that don't use any
| kind of magical construction techniques but have stuck around
| because of their value to the surrounding society and active
| efforts at preservation and/or repurposing.
| peoplefromibiza wrote:
| > which was that Roman buildings that remained standing did
| so because they were useful for some purpose,
|
| that's a fallacy.
|
| A lot of buildings were useful back then, it wasn't easy to
| build them nor cheap.
|
| But most of them collapsed, because they weren't strong
| enough.
|
| You get roman buildings everywhere in Europe and Northern
| Africa, a lot of civilizations lived there in the past 40
| centuries and their remains are scarce at best.
|
| It is like saying that Amazon beat many other startups of
| its times because they got lucky, it's simply because their
| execution was better than the competition.
| User23 wrote:
| > There are plenty of old buildings (such as Horyu-ji) that
| don't use any kind of magical construction techniques but
| have stuck around because of their value to the surrounding
| society and active efforts at preservation and/or
| repurposing.
|
| This is true, but rather misleading. Horyu-ji burned down
| and is probably around 80-90% new material.
|
| The Roman concrete structures on the other hand survived
| this long with their original construction materials.
| Linosaurus wrote:
| The article did bring up some ways modern concrete is
| superior in the shorter term:
|
| "Among the biggest obstacles to wider adoption of the Roman
| recipe are its long curing time - it can take up to six
| months to reach full strength, compared to standard
| concrete's' 28 days - and lower strength (Perucchio said it's
| approximately 10 times weaker than modern concrete),"
| JSavageOne wrote:
| You respond to an article detailing the superiors durability of
| Roman concrete with "they just chose to preserve these
| buildings" and "they just got lucky", cite no sources, and this
| is the top comment on this thread?
|
| Seems HN quality has gone downhill since what I last remember.
| cblconfederate wrote:
| They didn't use javascript?
| [deleted]
| agumonkey wrote:
| They did https://rome.tools/
| basementcat wrote:
| Rome wasn't written in a day.
| bennysomething wrote:
| Surely it should be "why are Rome's monuments..." Or am I
| mistaken, I'm not actually sure
| freefal wrote:
| Either reads fine to me.
| emmelaich wrote:
| 'how' sounds a bit wrong to me, too. But it's popular in the
| USA.
| nraynaud wrote:
| one very impressive feat is the Pont du Gard, this thing has been
| in disuse for 1500 years, and lots of stones have been looted
| over the centuries. And its aspect ratio is somewhat thin.
| wsinks wrote:
| Survivorship Bias
|
| The ones that are still standing were built really well. Each
| will have its own reason for standing so long.
| noyeastguy wrote:
| I wonder if there will come a time when society decides it's
| better to fix ruins such as the Colosseum and the pyramids
| instead of letting them just rot away.
| i_have_an_idea wrote:
| What would be the practical purpose of "fixing" something like
| the pyramids? Vs. just preserving them as-is.
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