[HN Gopher] Wavy walls use fewer bricks than a straight wall (2020)
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Wavy walls use fewer bricks than a straight wall (2020)
Author : caiobegotti
Score : 437 points
Date : 2023-07-27 13:16 UTC (9 hours ago)
(HTM) web link (twistedsifter.com)
(TXT) w3m dump (twistedsifter.com)
| LegitShady wrote:
| "Hackernews discovers first year university engineering
| statics/analysis from articles that are really just reposts of 3
| year old reddit content"
| pests wrote:
| Sorry, didn't realize you knew everything in the world already.
| LegitShady wrote:
| I avoid getting my knowledge of the world from reddit
| reposts, and yes, I did take first year statics, as well as
| structural analysis 1 and 2, wood design, concrete design,
| steel design, and masonry design.
| pests wrote:
| Congratulations.
| toss1 wrote:
| Very cool. So what is the optimal solution?
|
| To maximize the strength and minimize the bricks used, is a sine
| the best shape, or is there a better curve, and what is the best
| period and amplitude of the waveform? Does this solution change
| with the height of the wall?
| asimpletune wrote:
| Most likely you want the smallest curve that's achieves an
| acceptable amount of stability. Since the wave exists to
| prevent the wall from toppling, a pure sine is probably
| overkill.
|
| So I guess a factor then will be how tall your wall is. A very
| tall wall will need a deep wave, just like a wall one brick
| high would need no wave at all.
| HideousKojima wrote:
| If you follow the link in the post explaining the math behind
| everything, it says:
|
| "They use more bricks than a straight wall of the same thickness
| but they don't have to be as thick."
| judge2020 wrote:
| The post also says this in the first paragraph:
|
| > Popularized in England, these wavy walls actually use less
| bricks than a straight wall because they can be made just one
| brick thin, while a straight wall--without buttresses--would
| easily topple over.
| gymbeaux wrote:
| So wavy walls use more bricks than straight walls
| kgermino wrote:
| For the same function, wavy walls use fewer bricks
| adamc wrote:
| No, because they are stronger and can therefore be thinner.
| But the why is important.
| gymbeaux wrote:
| Wavy walls use more individual bricks, but less "brick"
| meesles wrote:
| Well, no. By length it's the same # of bricks if the wall is
| the same thickness.
|
| It requires less bricks to wall off an area using a single-
| layer wavy wall than it does with a double-layer straight
| wall
| [deleted]
| hammock wrote:
| In other words, a serpentine wall is stronger per amount of
| material used than a straight one. They also allow use of a
| single-thickness of brick without other supports
| eimrine wrote:
| I would say like it is less prone to tipping over per amount
| of material. It is not stronger in the meaning of holding
| bullets. Source: tried to build a brick construction once.
| 542458 wrote:
| True, but they use less bricks than a straight wall of the same
| strength, because the straight wall would have to be thicker or
| have buttresses. So it depends what you're doing - does the
| wall have to withstand that kind of loads or not?
| bell-cot wrote:
| > ...does the wall have to withstand that kind of loads or
| not?
|
| If you want the brick wall to last, and you aren't building
| it on either bedrock or a deep foundation ($$$) - then your
| three choices are (1) build it to withstand substantial
| horizontal loads, (2) pay more for regular maintenance, and
| (3) wall will topple due to forces from normal soil movement.
| adamc wrote:
| Came here to mention just that.
| Roark66 wrote:
| "Use, more bricks that the straight wall" misses a point a bit,
| because a straight wall like this would easily topple.
|
| A better description is "uses less bricks than a straight wall
| of equivalent resistance to horizontal forces"
| NeoTar wrote:
| "Popularized in England" - maybe popularized, but such walls are
| by no means popular or common.
|
| "The county of Suffolk seems to be home to countless examples of
| these crinkle crankle walls. On freston.net you can find 100 wavy
| walls that have been documented and photographed."
|
| Although it's not explicitly said, let's suppose that _every one_
| of those wavy walls is in Suffolk. The population of the county
| is 761 350 - let 's assume there are 100 000 homes (although
| there is the city of Ipswitch, it's otherwise largely a rural
| county where single-family homes will be common). So only roughly
| _one-in-one-thousand_ homes in Suffolk has such a 'wavy wall'.
| Elsewhere in the country probably even less - e.g. I've never
| seem one.
|
| Any for everyone complaining about mowing - do you actually have
| grass all the way up to your boundary wall? In my experience it's
| pretty common to have a flower bed running all the length of the
| boundary, so mowing would not be a problem.
| [deleted]
| em-bee wrote:
| _So only roughly one-in-one-thousand homes in Suffolk has such
| a 'wavy wall'_
|
| yes, but you also need to take into account how many homes have
| any brick wall at all.
| serial_dev wrote:
| > these wavy walls actually use less bricks than a straight wall
| because they can be made just one brick thin, while a straight
| wall-- _without buttresses_ --would easily topple over.
|
| And what about a straight wall with buttresses? Can we make them
| just as sturdy with fewer bricks?
| kristjansson wrote:
| No, that's sort of the point? There are fewer extra bricks used
| to make the curve than would be required to buttress /
| reinforce a straight wall.
| throw9away6 wrote:
| I've seen this design when making ultra light weight structures.
| It does work but can be difficult to manufacture
| DriverDaily wrote:
| Also, looks harder to mow the lawn.
| CrzyLngPwd wrote:
| But surely more fun :-)
| throw9away6 wrote:
| No lawns in metallic structures
| ilyt wrote:
| At cost of like 5x the space ? I guess if you have cheap land but
| bricks are at premium it makes sense
| omoikane wrote:
| I first learned about serpentine walls via splint, which is a
| linter for C. The serpentine walls were visible on the front page
| until 2020:
|
| https://web.archive.org/web/20200521064022/http://splint.org...
|
| The FAQ explains why they chose this logo: The
| walls are one brick thick, but because of their design are both
| strong and aesthetic. Like a secure program, secure walls depend
| on sturdy bricks, solid construction, and elegant and principled
| design.
|
| https://splint.org/faq.html#quest2
| carapace wrote:
| https://en.wikipedia.org/wiki/Gaussian_curvature
| jolt42 wrote:
| Has someone figured out the ideal frequency / amplitude of the
| wave? Maybe the frequency that matches the strength of a one-
| brick straight wall? The pictures strike me as possibly wavier
| than needed.
| adamrezich wrote:
| wouldn't that depend on how tall the wall is?
| ilyt wrote:
| It would be strength/brick use tradeoff.
|
| I want to know how that compares to just adding some rebar
| along the way
| geeky4qwerty wrote:
| This feels a bit like diet clickbait...
|
| "use fewer bricks than a straight wall"*
|
| *A straight wall of the approximal strength and length of a wavy
| wall, not just length.
|
| My counter would be that from a practical perspective the amount
| of space wasted by the wavy design seems to negate the usefulness
| of the design.
|
| Probably makes the lawn crew dizzy when mowing it too!
| wkdneidbwf wrote:
| this is an overly cynical take. headlines are brief by
| necessity. nobody would read that and think that a curved line
| from A to B is shorter than a straight line between the same
| points.
|
| the first paragraph explains it,
|
| > these wavy walls actually use less bricks than a straight
| wall because they can be made just one brick thin, while a
| straight wall--without buttresses--would easily topple over
| geeky4qwerty wrote:
| I recognize the cynicism in my observation, but is it fully
| unmerited?
|
| I put the following prompt in GPT4:
|
| create a professional title and a click bait title for the
| following article
|
| Then provided the article. This was the output:
|
| Professional Title: "Crinkle Crankle Walls: The Aesthetics
| and Efficiency of Serpentine Wall Construction"
|
| Click Bait Title: "You Won't Believe How These Weird, Wavy
| Walls Use Less Bricks Than Straight Ones!"
| 93po wrote:
| I think you overestimate what people would reactively think
| when reading this headline
| DrBazza wrote:
| The 'space wasted' on an estate of many hundreds, if not,
| thousands of acres is minimal. Given that often the bricks used
| were made and fired on site, it definitely saved on resources
| and labour.
|
| There's a stately home close to me that has a very short run of
| one of these walls, and the remains of the old brick kiln up on
| the hill side. If you know what you're looking for, you can
| also still see the hollows in the ground where the clay was
| dug, now fill of trees and bushes.
| Retric wrote:
| It cost even less labor to use minimal bracing for strait
| walls, these are curved for athletics.
|
| I suspect they are imitations of curved fruit walls popular
| in the 1600's before greenhouses took off.
| londons_explore wrote:
| I don't think this is the case.
|
| A wavy wall with a wave amplitude of X has the same
| toppling resistance as a straight wall with buttresses on
| both sides of length x/2.
|
| Assuming this stackoverflow answer is correct[1], the sine
| wave has (slightly) less bricks.
|
| [1]: https://math.stackexchange.com/a/1500468
| [deleted]
| Retric wrote:
| A single repetition of the wave is misleading. For N
| repetitions of the wave you need N + 1 buttresses not 2
| N.
|
| Also, while brick is stronger in compression a buttress
| increases toppling resistance in both directions so you
| need to consider material properties not just the
| geometry.
| chrisweekly wrote:
| "athletics" -> "aesthetics", right?
| hinkley wrote:
| > these are curved for athletics.
|
| Autocorrect strikes again.
| [deleted]
| [deleted]
| gweinberg wrote:
| Yes, it's clickbait and nonsense. Obviously a straight wall
| would use fewer bricks. Your brick wall is going to be one
| brick thick either way, nobody is going to try to somehow make
| the straight wall as strong as the wavy wall. Most likely the
| straight wall is already way stronger than it needs to be.
| turnsout wrote:
| If you have plenty of space but you're tight on money, it's an
| ingenious solution.
| geeky4qwerty wrote:
| Good point. I'd say if you're tight on money I'm not sure a
| wall should be at the top of your to-buy list.
| CalRobert wrote:
| I have a few acres of land and annoying neighbours. Stuff
| like this is relevant (though in the end I just went with
| hedging, which is cheaper and good enough for privacy)
| londons_explore wrote:
| Historically, lots of countries had laws saying you had to
| enclose your land. If you didn't, then you might lose it.
|
| In the days before wire, brick walls were a cheap
| longlasting enclosure method, especially if wood or stones
| weren't easily available.
| turnsout wrote:
| It is if you're selling sheep milk and you don't want to
| lose your flock.
| bee_rider wrote:
| I think that's typically a job for fences, right?
|
| This sort of wall is, I think, just an aesthetic way of
| marking a property line/get some privacy.
| toast0 wrote:
| Depends on how long you intend to keep livestock and what
| materials you have access to. Well built walls can last a
| lot longer than well built fences; but fences may be less
| costly initially. But it might also depend on how
| crafty/destructive your livestock is.
| devilbunny wrote:
| Drive through rural northern England and you will see
| _vast_ numbers of sheep moving through pastures that are
| bordered by old dry-stone walls. The roads will even have
| equestrian gates alongside them when they have stock
| grids to prevent the sheep from using the road.
|
| It's all about adapting to local materials. The same
| technique was used by early settlers in New England
| (think about the ending of _The Shawshank Redemption_ )
| because they had to get the stones out of the ground in
| order to plow and harvest - rather than just make a pile,
| they used the stones to build walls separating fields.
| gswdh wrote:
| [dead]
| scott_w wrote:
| It's relative. You might be "tight on money for building a
| wall" so you save money by building a wavy wall.
| [deleted]
| HWR_14 wrote:
| If you own a large amount of land than the savings add up.
| Especially if you live 250 years ago (or you want to match
| the walls from then) when bricks were not produced and
| delivered in massive industrial processes and large estates
| were more common.
| araes wrote:
| Even in the modern era the cost is still relevant. Bricks
| are still pretty expensive.
|
| If I have 100 acres (square), I need ~2.5 km of wall, at
| ~150,000 bricks for a 1m wall single brick-width wall
| (deter animals, mark property).
|
| At the online prices I'm seeing ($0.65), that's
| ~$100,000. If I have to make it all double width,
| suddenly its $200,000. $100,000 delta is still pretty
| relevant for a modern small scale farmer.
| HWR_14 wrote:
| The difference is people enclosing 100 acres today are
| either wealthy estates or using non-brick fences for
| farmers.
| BurningFrog wrote:
| Pre industrialism, almost everyone was dirt poor by current
| standards.
| seabass-labrax wrote:
| They were also dirt poor by current standards after
| industrialism started. It was well into the 19th century
| that laws like the Education Act of 1870 and the Trade
| Union Act of 1871 started distributing power to the
| common people of Britain outside of the traditional
| quasi-feudal system.
| oatmeal1 wrote:
| Also IMHO it looks horrible.
| amelius wrote:
| The solution for the space problem is obvious: just make the
| wall wave in the longitudinal direction instead of the
| transversal direction.
| surfpel wrote:
| > This feels a bit like diet clickbait...
|
| This is fun clickbait. Straight to the point, totally random
| quirky trivia, and most of the page is nice pictures. Love it.
| tetrep wrote:
| > *A straight wall of the approximal strength and length of a
| wavy wall, not just length.
|
| The article suggests that, if you attempted to build a straight
| wall with a similar amount of bricks, that it would not be able
| to be freestanding (i.e. it would need to be buttressed or it
| would fall over). That's a significant feature of a wall to
| some people, so I don't think it's fair to dismiss the utility
| of that by suggesting that it's simply "less bricks for
| comparable strength," it's "less bricks for a freestanding
| wall."
|
| If you want a freestanding brick wall, this seems to be the
| "ideal" way to do it, assuming you have the space required for
| the wave. I think the space needed would be a function of the
| wall height, so if you need a tall wall, you need more
| horizontal space for the wave and a wavey wall becomes less
| ideal.
| kbenson wrote:
| > so if you need a tall wall, you need more horizontal space
| for the wave and a wavey wall becomes less ideal.
|
| Not necessarily. You might need a straight wall to be thicker
| or have more buttressing in that case as well. The
| requirements for each (waviness, thickness, buttressing)
| likely change to different degrees based on height, so wavy
| walls could become less ideal, or they could become _more_
| ideal.
| hammock wrote:
| Do you also think corrugated cardboard is wasteful?
| geeky4qwerty wrote:
| Yes, of course I do, just like I believe that the Australia,
| like false equivalencies, don't exist.
| vehemenz wrote:
| The extra space doesn't have to be fully wasted. You could
| plant bushes or small trees in the concave sections.
| Lutger wrote:
| Indeed. Historically these walls have been used in orchards,
| where they are ideal. The wall serves an important function:
| it buffers heat. This can make all the difference, especially
| in late frosts, which are doom for the bloom. Of course, the
| added warmth can also mean you can grow varieties in a colder
| climate that you normally wouldn't be able to.
| hammock wrote:
| Applies to flat walls not wavy, but espalier,[1] a way to
| cultivate trees in tight spaces, is one of my favorite things
| ever.
|
| [1]https://en.wikipedia.org/wiki/Espalier
| jacquesm wrote:
| I'm doing this with an apple tree right now :)
| developer93 wrote:
| I mean I don't see a reason why it couldn't be applied to
| wavy walls if they were high enough, it's just training
| isn't it?
| hammock wrote:
| Fair point. I've personally never seen it
| ZeroGravitas wrote:
| This article mentions them, with photos:
|
| https://www.lowtechmagazine.com/2015/12/fruit-walls-
| urban-fa...
|
| Serpentine or Crinkle-Crankle walls, apparently a Dutch
| innovation.
|
| > Although it's actually longer than a linear wall, a
| serpentine wall economizes on materials because the wall
| can be made strong enough with just one brick thin. The
| alternate convex and concave curves in the wall provide
| stability and help to resist lateral forces. Furthermore,
| the slopes give a warmer microclimate than a flat wall.
| This was obviously important for the Dutch, who are
| almost 400 km north of Paris.
|
| > Variants of the serpentine wall had recessed and
| protruding parts with more angular forms. Few of these
| seem to have been built outside the Netherlands, with the
| exception of those erected by the Dutch in the eastern
| parts of England (two thirds of them in Suffolk county).
| In their own country, the Dutch built fruit walls as high
| up north as Groningen (53degN).
| nottorp wrote:
| Interesting, locally the same word is used for the
| structures used for cultivating climbing plants. Haven't
| really seen it done with trees.
| mattmaroon wrote:
| It depends how you define "wasted". If it were a flat wall,
| it'd give the interior more space by just pushing it out to
| the furthest point in the wavy wall. I guess you could say
| that whatever the magnitude of the wall is would be wasted.
| tomxor wrote:
| Walls have purpose beyond neatly cut lawns.
|
| This wall would work well at road field boundaries where a
| couple feet makes less practical difference than the large
| saving in materials.
| yboris wrote:
| Every dip in the wave is an opportunity to plant beautiful
| bush, flowers, or shrubbery.
| travisgriggs wrote:
| Amen to this. In a tabloidish sense.
|
| I read the title and thought "duh". Maybe others were intrigued
| and clicked, but for me, this is just obvious. I had lots of
| legos, and own more now as a grandpa than, er, uh, I should. I
| guess spatial reasoning about bricks just is second hand at
| this point.
|
| What the article likely leaves out, is that the all of the
| "corner only" touch points are going to create a more "pourous"
| wall. And collection points for crap.
| pm215 wrote:
| You can see from the photos in the article that the amount of
| waviness is not so large as to result in large angles between
| adjacent bricks -- the usual mortar between bricks connects
| them and doesn't even look like it's all that much larger a
| mortar join than for a straight wall.
| gowld wrote:
| The important part is
| https://www.johndcook.com/blog/2019/11/19/crinkle-crankle-ca...
| [deleted]
| fnord77 wrote:
| looks infuriating to mow around
| Prcmaker wrote:
| The same reason is why my roof has corrugated metal sheeting,
| rather than plate.
|
| This was a question I had students prove out. With the bending
| moment of inertia being related to the cube of the thickness for
| a flat plate, the maths trickles out very quickly.
| badcppdev wrote:
| We need your expertise here please:
| ttps://news.ycombinator.com/item?id=36899973
| Lio wrote:
| I saw the title and instantly thought, of Suffolk, England.
|
| Quite pleasing to see it referenced in the article too.
|
| Proper Suffolk that, like little pink cottages and good
| _quawlity_ tea towels[1]. :D
|
| 1. https://m.youtube.com/watch?v=6-7hcPXwpBQ
| cantSpellSober wrote:
| No they don't
|
| > [Wavy walls] use _more_ bricks than a straight wall _of the
| same thickness_
|
| However they "resist horizontal forces, like wind, more than
| straight wall would."
|
| > So if the alternative to a crinkle crankle wall one-brick thick
| is a straight wall _two or more bricks thick_ , the former saves
| material
|
| https://www.johndcook.com/blog/2019/11/19/crinkle-crankle-ca...
| surfpel wrote:
| If a one brick thick straight wall can't stand, then you don't
| have a wall you have a pile of bricks. It's pointless to
| consider the impractical case.
| cantSpellSober wrote:
| Most _will_ stand unless they need high wind resistance (or
| are buttressed).
|
| There are _many_ practical cases for a straight wall of
| bricks, it 's not an "impractical case."
| surfpel wrote:
| > > If a one brick thick straight wall can't stand
|
| Caveat there is quite significant.
|
| > There are many practical cases for a straight wall of
| bricks
|
| Indeed the vast majority of cases yes.
| jamesmurdza wrote:
| This looks similar to the way corrugated steel is harder to bend
| due to a higher "area moment of inertia".
| nonethewiser wrote:
| I see this a lot in the rural US with wooden fences but had no
| idea why it was done, but I guess its for the same reason
| (stability). Apparently they've done it since the 1600s.
|
| https://www.louispage.com/blog/bid/11160/worm-fence-what-is-...
|
| Still, this seemed totally unecessary until I realized this mean
| they dont have to put any posts into the ground. No digging
| holes, which would be really nice when you're trying to fence up
| very large acreage.
| gxs wrote:
| Interesting pictures.
|
| Not a complicated subject, but somehow seeing it with straight
| lines made it completely obvious and intuitive vs the wavy
| wall.
| autoexec wrote:
| The US is so bad at naming things!
|
| A Serpentine Wall sounds better than a Worm Fence or Snake
| Fence.
|
| Crinkle Crankle Wall is a bit more fun than ZigZag Fence.
|
| A Ribbon Wall seems like a nice thing to have on your property
| vs a Battlefield Fence.
| jrockway wrote:
| I'd've called it a chazzwozzer.
| version_five wrote:
| They're in the lorry and the larder and...
| mcpackieh wrote:
| That's just like, your opinion man. Worm is a cool word.
| Maybe we can compromise and call it a wyrm fence.
| autoexec wrote:
| Wyrm fence is a great name! I'd use one to keep my hoard of
| treasure safe
| oxygen_crisis wrote:
| A worm fence sounds like it should be a couple inches tall
| and several feet deep, to block the worms.
| NavinF wrote:
| I'd _much_ rather have a Battlefield Wall on my property in
| the US than a Ribbon Wall or Crinkle Crankle Wall. The latter
| two sound ridiculous. I really like "Serpentine Wall", but
| it sounds a little too technical for everyday conversation
| with nontechnical people
| autoexec wrote:
| I suppose it's subjective but Crinkle Crankle is better
| _because_ it sounds so ridiculous.
|
| Ribbon Wall doesn't sound any more ridiculous than same-
| shaped Ribbon Candy
| (https://en.wikipedia.org/wiki/Ribbon_candy) or Ribbon
| Cables (https://www.fxpstore.com/wp-
| content/uploads/2020/09/ribbon-w...), and ribbons don't
| call to mind atrocities or human suffering. Battlefields
| are terrible places where horrific things happen. That's
| not something I'd want associated with my own property.
| hfivivfub wrote:
| The value in this is the historical dimension.
| Apparently, "crinkle-crankle" dates to 1598. So it's a
| pre-US term.
|
| I agree that it's not a good look to automatically prefer
| the military term to the "ridiculous" one. It smacks of
| toxic masculinity.
|
| "Crinkle-crankle" is obviously archaic, and it evokes
| folk art and (in the US) colonial culture. That is fairly
| neutral, as placenames go.
| ChainOfFools wrote:
| Crinkle crinkle wall has to be the most British sounding
| britishism ever. Like something that would have been a
| subject of serious research at the Ministry of Silly
| Walls.
| fsckboy wrote:
| > _The latter two sound ridiculous. I really like
| "Serpentine Wall", but it sounds a little too technical for
| everyday conversation with nontechnical people_
|
| ribbon sounds ridiculous and serpentine sounds technical?
| you are not a boomer. "Serpentine, Shel, serpentine!" --
| Peter Falk
|
| https://www.youtube.com/watch?v=A2_w-QCWpS0
|
| Alan Arkin just died recently, RIP
| tssva wrote:
| The park service uses this type of fencing a lot.
| helb wrote:
| they don't use less wood than a straight fence though :)
| shirleyquirk wrote:
| they should be able to. same physics applies, right? poles
| dont have to be as thick or as deep to resist the same
| torque, and if you could somehow make the pales
| curvy/corrugated, they could be thinner, too.
| sn9 wrote:
| Wooden fences tend to be only a plank thick, so there's no
| savings like there are with brick walls where the savings
| come from getting to build a single layer thick.
| Cerium wrote:
| Those fences are also popular in places where it is cold in the
| winter. No posts in the ground means no frost heave. A fence
| like that can sit unmaintained for decades before it starts to
| fall apart.
| bin_bash wrote:
| it's not for stability, it's because it doesn't require posts
| so it's cheap and quick
| drtz wrote:
| But it is for stability. Try making a straight fence with no
| posts and see how stable it is.
| gowld wrote:
| Lots of things "don't require posts so it's cheap and quick",
| but this version makes a stable wall.
| nonethewiser wrote:
| > it's not for stability, it's because it doesn't require
| posts
|
| That's stability
| silisili wrote:
| Not a physics person...but is this similar to the effect of
| 'rolling' thin pizza so it won't droop? Or is it strictly about
| being better at wind resistance?
| javier123454321 wrote:
| Yeah but more space, and are therefore the wrong choice a lot of
| the time.
| deaddodo wrote:
| Which is why they are very popular in the less densely
| populated and large lot size areas of the English Country side.
| By the time of the New World, fast population growth meant the
| economics of brick production wasn't feasible and copious
| alternative methods were easier (wood/picket fences, wood
| studs+wire, chain-link or wrought iron/brick + iron). All less
| long lasting, but cheaper, quicker and easier to install with
| almost the same benefits (fencing of pets + livestock, property
| demarcation, security). Which is why you don't see them nearly
| as often outside of Europe (Asia having used their own
| alternatives better suited for their environment and needs,
| Africa having had New World techniques used during
| colonialism).
| Slava_Propanei wrote:
| [dead]
| csours wrote:
| Or it's a way to brag about how much space you have.
| FrustratedMonky wrote:
| Yeah. Like how Lawns were a way to brag about how much land
| you have.
|
| "Look, I have so much land I can just grow grass instead of
| crops, you plebs".
| Sharlin wrote:
| And the lawns of today's middle class are of course still
| about signaling, it being very humsn for people to try to
| raise themselves up by adopting and imitating the lifestyle
| and customs of the class above them. "Look, I have enough
| leisure time to spend on an entirely superfluous activity!"
| or "Look, I'm wealthy enough to pay somebody to engage in
| an entirely superfluous activity!"
|
| Particularly in arid climates it's also "look how much I
| can afford to waste perfectly good drinking water!"
| ehnto wrote:
| Something that gave me a chuckle growing up where I did
| in Australia: everyone's lawn died in the summer. You're
| weren't allowed to water it enough due to drought
| measures, and the summers are so hot they die off on the
| first heat of the season.
|
| I notice a lot more people ditch the lawn for native
| plants now. Sure does look a lot less futile than
| spending a third of your lot on dead grass.
|
| Many memories playing cricket on dry, prickly, dead grass
| as a kid.
| episiarch wrote:
| Lawns don't usually die in the summer, they go dormant.
| You can usually distinguish between dead grass and
| dormant grass by observing the color: dormant grass is
| yellow, while dead grass is grayish.
|
| Texas lawns commonly use some form of bermuda grass,
| which goes dormant during the hot season (typically late
| July to late September). Some lawns will mix in a rye
| grass which shows bright green color during this same
| season to preserve the look, but obviously this
| compromises the growth of both types of grass.
| Jemm wrote:
| fewer bricks than a straight wall with supports.
| Terr_ wrote:
| Another reason for some a wavy walls involves capturing more heat
| from sunlight over the course of a day, in this example for
| nearby plants:
|
| > The Dutch, meanwhile, began to develop curved varieties that
| could capture more heat, increasing thermal gain (particularly
| useful for a cooler and more northern region). The curves also
| helped with structural integrity, requiring less thickness for
| support.
|
| [0] https://99percentinvisible.org/article/fruit-walls-before-
| gr...
| PawgerZ wrote:
| I learned about this and a lot more about walled gardens when I
| searched for the orgin of the term "walled garden" to do with
| technology today.
| anArbitraryOne wrote:
| Would it be stronger for the same amount of bricks if it didn't
| have the inflection point where there is no curvature, and
| instead had intersecting arcs like: >> >> >> >> ?
| Prcmaker wrote:
| I think it would be less strong than a wavy wall of similar
| brick count, but still more efficient than an equivalent
| strength wall built in a straight line.
|
| My mental reasoning for this is that a (pseudo) sinusoid spends
| a lot more of its path further away from the centre. Thinking
| of it as a point moving along the path through time, it will
| dwell and the peaks, and cruise through he centre. The
| contribution of each brick to wall stiffness will be related to
| the cube of the distance from the centre line (neutral axis),
| so more 'time' spent at the peaks is best. This holds true on
| the macro scale, but could vary on the scale of a half
| 'wavelength' as the lack of inversion of curvature could be
| beneficial there.
|
| Everything moderately reasonable seems to be better than a
| straight line in this instance. In the limit, two much thinner
| walls, far apart, is the optimal solution, but that becomes
| unreasonable as those walls must be coupled together to provide
| strength.
| badcppdev wrote:
| I think you're asking if a series of arcs is stronger than a
| wavy line. It's a great question and I think the answer to that
| would require a full model of the two walls to calculate all
| the stresses, etc. But I think it would also depend on the
| question of "stronger against what?" A pushing force but at
| what point and at what angle. Even height might make a
| difference.
|
| My gut instinct is that the point where a wavy wall changes
| from curving one way to another is a slight weak point and
| perhaps an angle there would actually be stronger. Might be
| totally wrong.
| kulor wrote:
| Tangentially related; as covered in The Blue Factory
| documentary[1], one of the challenges with the EB110's design was
| its flat sides. Curved body panels provide greater strength and
| importantly, reduces vibrations.
|
| FWIW The Blue Factory had the same kind of charm as the General
| Magic documentary
|
| 1. https://www.imdb.com/title/tt6301490/
| fredley wrote:
| In the UK these ate known by the wonderful term "Crinkle crankle
| wall"
| Underphil wrote:
| That is written in the best first paragraph of the article.
| MR4D wrote:
| TLDR: they don't need buttresses, hence the savings.
| pfdietz wrote:
| The labor to build such a wall may dominate the savings in brick.
| But if you're building a brick wall, maybe you don't care much
| about either.
|
| I wonder if this sort of structure could be built by 3D printing,
| say with concrete or even soil.
| devilbunny wrote:
| Labor is pretty much directly proportional to number of bricks
| placed. If you save on bricks, you save on labor.
|
| If that was your point, sorry for misreading you.
|
| In the era in which these were commonly used, bricks were
| largely made on-site or very nearby. So you saved on labor
| twice - once to make the bricks, and again to place them.
| pfdietz wrote:
| I was thinking of a comment in the John Cook link, where
| someone was saying these are fiddly to build compared to a
| conventional brick wall.
| devilbunny wrote:
| They're certainly fiddly to plan out compared to a straight
| wall (where all you need is a long piece of twine anchored
| at each end), but I assume that those building them use
| some kind of forms to help keep the angles correct.
| etskinner wrote:
| There's actually a similar concept in 3D printing called gyroid
| infill, it's essentially a 3D version of the wavy wall:
|
| https://www.wevolver.com/article/understanding-the-gyroid-in...
| jansan wrote:
| Of course title is a bit of a clickbait, because they are
| comparing walls of same strength, not single row straight walls
| with curved walls.
|
| But how does this compare with a straight wall with brick columns
| every two meters or so? My guess this is the best compromise, and
| maybe that is the best compromise, as it uses about the same
| number of bricks as a curves wall, but the area wasted is much
| smaller.
| dtgriscom wrote:
| There's been a one-brick-thick wavy wall off a busy road in
| Cambridge for at least fifty years:
| https://goo.gl/maps/sxTsPW71F317gwK88
|
| It kept getting hit by cars until they finally installed a guard
| rail.
| gottorf wrote:
| Driving in the Boston area is hard enough already, we don't
| need to add wavy walls into the mix ;-)
| xxpor wrote:
| It took me way too long to see that the cars are driving on the
| right, so this is Cambridge MA, not Cambridge UK.
| andai wrote:
| Does something about this design make it more likely to get hit
| by cars?
|
| I guess the force of impact would be greater relative to
| scraping a straight wall.
| dontrustme wrote:
| if you think of it from the context that the diagonal length of a
| brick is it's longest dimension, you can start to intuitively
| imagine how this efficiency in layout pattern is achieved.
| dontrustme wrote:
| -signed, an architect
| CodeSgt wrote:
| I feel like everyone this far is missing something, or perhaps
| just I am.
|
| I understand that a wavy wall will be stronger than a straight
| wall of the same thickness, therefore if you need that additional
| strength it technically uses fewer bricks to reach it.
|
| That said, if the alternative is a 2 layer straight wall, is the
| wavy wall equally as strong? Or is it just stronger than the
| single layer wall?
|
| Without knowing anything about the subject matter, I'd assume
| that the strength goes in order of single-layer straight, wavy,
| double-layer straight. No? Seems like needing just the amount of
| strength the wavy wall provides, and no more, would be a fairly
| rare use case. Leading to double-layer straights most of the time
| anyway.
| chaostheory wrote:
| Well, tbf the article doesn't even try to explain how wavy
| walls are stronger than straight ones, or how fewer bricks are
| needed.
| amelius wrote:
| It doesn't need to, a child understands this. The only thing
| the article needed to explain was how the title should be
| interpreted, and it did fine in this respect.
| ethanbond wrote:
| It's a matter of stability more so than "strength", no? Having
| never attempted to push over a brick wall, I'd guess that it'd
| be easier to do so for a straight double wythe than a wavy
| single... but yeah, baseless intuition here!
|
| The base of a double wythe wall is still only like 7", which if
| you're stacking say 84" of brick on top of that... seems pretty
| unstable to me.
| horsawlarway wrote:
| The wavy design is probably just as strong as the double layer
| (possibly stronger depending on the direction of force).
|
| The issue with a single layer wall isn't really the strength
| between bricks, or the bricks themselves - it's that a single
| layer wall has a very narrow base and is subject to tipping
| over.
|
| The wave in the design makes the base of the wall act is if it
| were MUCH wider, preventing the tipping action of a single
| layer.
|
| So the wavy design is only as strong as single layer of bricks,
| but it has a base 2 to 3 times the width of even the double
| layer wall designs. It will be much more resistant to tipping
| forces, but less resistant to impact forces.
|
| The thing about most walls is they aren't really load bearing -
| they just delineate owned space - so the wavy design is great
| for large properties. Much less great if it's a tiny space and
| you're losing a good chunk of sqft to the wave.
| ke88y wrote:
| Additionally: you need the wall to be "stable enough", not
| "equally as stable as a double-layer base". Possibly, double-
| layer brick walls are over-engineered.
| gswdh wrote:
| [dead]
| HWR_14 wrote:
| "Strength" is used to refer to things like wind hitting the
| wall, not a car. That is, the wall toppling, not breaking. So
| the wavy wall with its wide base is quite strong.
| andy800 wrote:
| The University of Virginia, designed by Thomas Jefferson,
| features numerous brick serpentine walls.
|
| https://www.google.com/search?q=uva+serpentine+walls&tbm=isc...
| throwaway894345 wrote:
| I'll save folks some reading: they're comparing a very thick
| straight wall with a much thinner wavy wall.
| deaddodo wrote:
| The primary point is that you can't make an equivalently thin
| straight wall due to natural (wind and gravity, primarily)
| forces. Kinda weird to summarize it without the crux of _why_.
| throwaway894345 wrote:
| > Kinda weird to summarize it without the crux of why.
|
| I agree, the headline did a very poor job of summarizing.
| dang wrote:
| Related:
|
| _Crinkle Crankle Wall_ -
| https://news.ycombinator.com/item?id=33155781 - Oct 2022 (1
| comment)
|
| _Wavy walls use fewer bricks than a straight wall (2020)_ -
| https://news.ycombinator.com/item?id=25359550 - Dec 2020 (1
| comment)
|
| _Crinkle Crankle Wall_ -
| https://news.ycombinator.com/item?id=21554986 - Nov 2019 (56
| comments)
| spread_love wrote:
| Another "article" summarizing a reddit post. They even took the
| top comment and put it at the end
|
| > _wavy walls that lawnmowers surely detest!_
| BobMackay wrote:
| I think one should also consider the failure modes when, for
| example, a tree falls into the wall. For a straight wall, it is
| possible that a falling section will propagate the failure along
| the entire length of the wall. For a wavy wall, it is likely to
| fail in shear, limiting the damage to one section.
| hyperhopper wrote:
| This headline is awful and sounds sensational.
|
| Better headline would be "wavy walls use fewert bricks than
| thicker straight walls"
| ilyt wrote:
| and like 5x the space
| rkagerer wrote:
| TLDR: Because they can be one brick thin. The waviness works just
| like corrugated cardboard.
| hammock wrote:
| Corrugated cardboard just is a wavy wall, sandwiched in between
| two straight walls.
|
| You can also observe corrugated steel and its use in
| construction, shipping containers, etc. Because these are steel
| and stronger than paper, the sandwich layers are not needed
| oniony wrote:
| You can also peel the label of a tin (can) of baked beans in
| your cupboard to see the the ripples added for rigidity.
| finnh wrote:
| as a bonus, they make canned cranberry sauce visually
| appealing on the Thanksgiving platter :)
| singleshot_ wrote:
| Ever notice there's a subtle fold in the shape of an "x" in
| the middle of the sheet metal panels that make up ductwork?
|
| Undulations for rigidity are everywhere!
| vharuck wrote:
| Soda cans also have a counterintuitive efficiency feature:
| concave bottoms. If a can with a flat bottom held the same amount
| of soda, it would be shorter and have less surface area, but its
| metal body would need to be thicker to withstand the same
| pressure. In the end, it'd require more aluminum.
|
| https://www.csmonitor.com/Science/Science-Notebook/2015/0414...
|
| ^Probably not the best article for this, but it was easy to find
| and has a link to a chemical engineer's video.
| oxygen_crisis wrote:
| Same principle as concave bottoms on wine bottles (though the
| concern there is more about jostling and impact during
| transport than pressurized contents).
| jerry1979 wrote:
| I think the Christian Science Monitor is perfectly fine.
| https://mediabiasfactcheck.com/christian-science-monitor/
| WorldMaker wrote:
| The religious group that funds it has a questionable
| relationship to science including and despite "Science" being
| in its name. (It was started as a 19th Century anti-hospital
| group. We'd consider them "proto-anti-vax" in today's
| concerns and terminology.) They may be unbiased in reporting
| the news, generally, but there's still concerns about their
| relationship to reporting science given their name and the
| known beliefs of their church.
| yetanotherloser wrote:
| ...being anti-hospital in the 19th century sounds fairly
| rational to me?
| WorldMaker wrote:
| Sure, you can't fault them for not having some good
| reasons behind their beliefs, based on what they knew and
| experienced at the time. You _can_ certainly fault them
| for calcifying those beliefs into an entire church with
| rituals /rites devoted to such beliefs that then became
| somewhat obstinate in the face of later scientific
| progress and technological advancement (and then because
| of that also complicit in later struggles of science
| versus pseudo-science and conspiratorial thinking).
| zhte415 wrote:
| Aluminium's also more expensive than steel but experiences
| sufficiently less breakage to justify the price.
| anamexis wrote:
| Engineer Guy (Bill Hammack) has a great video about this.
|
| https://www.youtube.com/watch?v=hUhisi2FBuw
|
| Edit: Just realized this is the same video you referenced. All
| of his work is fantastic.
| hinkley wrote:
| I really liked this video when I watched it. I may have
| watched it twice.
| mcpackieh wrote:
| I've encountered a few of his videos on wikipedia (creative
| commons license.) Pretty neat.
|
| His 'drinking bird' video is used on the wikipedia page for
| the same: https://en.wikipedia.org/wiki/Drinking_bird#Physica
| l_and_che...
| pletnes wrote:
| Also in the current design you can stack them. This is probably
| worth something in terms of wrapping of pallets of cans.
| [deleted]
| gowld wrote:
| Standard video:
|
| "The Ingenious Design of the Aluminum Beverage Can"
|
| https://chbe.illinois.edu/news/stories/engineer-guy-ingeniou...
|
| https://www.youtube.com/watch?v=hUhisi2FBuw
| Cthulhu_ wrote:
| Same with cans, corrugated sides, tops and bottoms are for
| strength and pressure resistance. Actually most corrugated
| anything is done so for strength.
| codyb wrote:
| I think that's also why a pretty small kink in the can will
| make it tremendously easier to crush against your forehead as a
| party trick :-)
|
| Or, more likely, it's a similar principle also at place in the
| design.
| 3cats-in-a-coat wrote:
| Same about waviness on plastic bottles.
|
| https://www.riverkeeper.org/wp-content/uploads/2018/04/bottl...
| rvba wrote:
| The waviness around makes it easier to hold them too.
| Although to some degree it might be marketing as well?
| 3cats-in-a-coat wrote:
| It's a combination of structural variation, like with the
| bricks, and branding. Because as long as it's "waving" it
| doesn't matter how _exactly_ it waves except in some
| critical areas, like where you hold it, the bottom and the
| top.
| tonmoy wrote:
| Not sure about the actual function that defines the wave, but
| let's assume they are convex and concave semi circles. Then to
| make a wall of length L with bricks of l length, we need pi _L /l
| number of bricks. The linked Reddit post says a straight wall
| needs to be 2 bricks wide to have the same length, which needs
| 2_L/l number of bricks which is fewer than the wavy walls
| eastof wrote:
| It's not one giant semi circle. Lets say each semi-circle has a
| radius of about 2 ft (judging by the pictures). Every 8 ft
| section (1 wave/one full cicle) takes 2 _pi_ 2 ~= 12.56, while
| the straight wall takes 8*2 = 16 bricks.
| contravariant wrote:
| Semicircles seem excessive. At no point does the wall have an
| angle over 45 degrees, so a semi-circle which would be at a 90
| degree angle for every inflection point seems _way_ too wavy.
|
| A sine wave is probably closer, which would give an arc length
| of sqrt(1+cos(2pix/L)^2). This has no reasonable closed form I
| can find but it seems like it would be about 21% longer than a
| straight line.
|
| Edit: Also a semicircle is pi/2 times as long as its diameter,
| not pi times.
| hinkley wrote:
| Sines are about 1/.7 (40%) longer aren't they?
| contravariant wrote:
| What would be about what you'd get if you made a sawtooth
| out of straight sections, pretty sure that's quite a bit
| longer than a sine wave would be.
| hinkley wrote:
| Yeah I'm thinking of electricity.
|
| A right isosceles triangle has a hypotenuse that's [?]2
| (1.41) and 1/[?]2 = 0.71.
|
| Stack Overflow seems to think it's around 2.4x, but I am
| not sure I could ever follow the math and I certainly
| can't now. I think the amplitude makes the difference
| here and SO is answering a different question, otherwise
| this article would be wrong and that wasn't my impression
| the first time I encountered this topic.
|
| second edit: The article linked from this article says:
|
| So a crinkle wall with amplitude 1.4422 uses about as
| many bricks as a straight wall twice as thick.
| tln wrote:
| Article links to this post with another derivation.
|
| https://www.johndcook.com/blog/2019/11/19/crinkle-crankle-ca...
|
| I'd like to know if this wavy wall technique requires non-
| square bricks to be stronger. And is it stronger against
| sideways forces along the concave and convex sections. If it's
| only the same strength as a straight wall then I'd think it'd
| be worse as a retaining wall?
| gowld wrote:
| Corrected link:
| https://www.johndcook.com/blog/2019/11/19/crinkle-crankle-
| ca...
| dang wrote:
| Thanks! I've corrected the link in the GP comment.
| nfriedly wrote:
| I believe I've read that some plants do better when planted in
| the concave portion of a wavy wall, because the bricks absorb
| warmth during the day and release it at night.
| tokai wrote:
| Fruit Walls
|
| https://99percentinvisible.org/article/fruit-walls-before-gr...
| trhr wrote:
| Given how much OCD I have about naming variables and writing unit
| tests, I think if this was in front of my house, I'd take a
| sledgehammer to it. Fences shall be straight, damnit.
| esafak wrote:
| So, when it comes to pressure, the straight wall isn't "gonna
| take it"?
|
| (twisted sifter)
|
| I'll show myself out.
| qwertox wrote:
| Did my adblocker accidentally filter out the explanation?
|
| Following the link which is supposed to explain another thing,
| why it is more resistant to lateral forces, it contains an
| explanation:
|
| > The parameter a is the amplitude of the sine wave. If a = 0, we
| have a flat wave, i.e. a straight wall, as so the length of this
| segment is 2p = 6.2832. If a = 1, the integral is 7.6404. So a
| section of wall is 22% longer, but uses 50% less material per
| unit length as a wall two bricks thick.
|
| "as a wall two bricks thick". Hmmm. Even bigger savings as a wall
| three bricks thick.
| secondcoming wrote:
| You need to use two brick width for stability.
| qwertox wrote:
| Is that what we're doing? If I remember correctly, the walls
| around the houses in my childhood neighborhood were only one
| brick in width. Also walls around cemeteries and such, I
| could swear they are not double-width walls.
| Rumudiez wrote:
| Those are just veneers. My grandfather was a professional
| brick and stone mason. You can tell if a brick wall is load
| bearing if it has alternating directions: every so many
| bricks you'll see one or more that's been rotated 90deg to
| connect the layers together
|
| Veneer, all the bricks are in the same orientation: https:/
| /i.pinimg.com/originals/1b/65/ec/1b65ec6fdb488d3dab28...
|
| Supporting wall, notice the alternating pattern:
| https://www.backwoodshome.com/bhm/wp-
| content/uploads/2015/12...
| aeyes wrote:
| One brick wide walls often have a thicker pillar for
| stability every couple of meters.
| londons_explore wrote:
| And two brick thick walls often have pillars... So
| pillars aren't a good indicator.
| AnimalMuppet wrote:
| The point is that a straight wall one brick thick will fall
| down.
|
| Though I didn't see any real explanation of _why_ a straight
| wall one brick thick will fall down...
| jguimont wrote:
| Ever built Lego?
| AnimalMuppet wrote:
| Maybe, a long time ago.
|
| For those whose childhood is a long way behind them, would
| you explain?
| jguimont wrote:
| Lego are just like those brick. If you just pile them on
| you have no strength, if you interlock them you have
| strength in one direction, if you have 2 rows
| interlocked, you have strength in 2 directions.
| drakythe wrote:
| Imagine a posterboard, one of those 3 section things you
| can by at a supermarket kids use in science fairs. What
| happens if you attempt to stand that posterboard up with
| the sections in a strait line? Now take the outer two
| sections and place them at an angle to the central board.
| One will fall over by itself. The other will stand
| upright and even take a non-trivial amount of downward
| pressure (weight) before it falls over.
|
| It works the same way with any thin and tall building, it
| needs to have support perpendicular to the main body.
| You'll note that most straight brick walls have thicker
| "towers" at regular intervals. Or it needs underground
| support, like concrete in the ground for a fence post.
|
| Unrelated: Go buy a lego set! If you've forgotten the joy
| of LEGOs I encourage you to rediscover it. The kinds of
| sets they have available these days are vast and the
| cleverness of their building techniques needs to be seen
| to be appreciated.
| di456 wrote:
| The base proportion to the height.
|
| Two bricks wide has a 2x wider base.
| deaddodo wrote:
| It doesn't have the vertical stability to stand on its own.
| You need to make it thicker (how thick depends on how tall,
| but the important aspect is the staggered construction of
| multiple layers giving a similar self-reinforcement) to give
| it the proper foundation. Keep in mind that it's multiple
| thin horizontal layers held by a relatively weak adhesive,
| not a solid object.
|
| A wavy wall reinforces itself against the same forces (wind
| being the big one) allowing for thinner construction at an
| equivalent height.
| ilyt wrote:
| Take a piece of paper. Try to put it on its edge. Now bend
| the paper in zigzag and try again
| alecst wrote:
| > As for the mathematics behind these serpentine walls and why
| the waves make them more resistant to horizontal forces like wind
| vs straight walls, check out this post by John D. Cook.
|
| The linked post does not explain why the walls are more resistant
| to forces. It just calculates the difference in length.
| paiute wrote:
| https://www.johndcook.com/blog/2019/11/19/crinkle-crankle-ca...
| jwilk wrote:
| That's the same post that is linked from the original
| article.
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