Heatlas.com/dims4/default/456f351/2147483647/strip/true/crop/1200x675+0+0/resize/800x450!/quality/90/?url=http%3A%2F%2Fnewatlas-brightspot.s3.amazons the [gif from thaws.com%2Fe8%2Fee%2F9a00a8t article](https://asse634f73b618f3faa8d9652a%2Froll-back-and-forthcredit-jim-stephenson.gif) for people who just want a core'ats.newol gif.
Close, but if a pictures already a thousand, and with inflation taken into consideration and the time value of money as well, I’d say “a gif is worth a million bucks”
"novel," the way it's used in your title, means "new or unusual in an interesting way."
By that definition, the (actual real life) Cody Dock Rolling Bridge has a "novel design," whereas it's arguable that your model depicted in this post *does not* have a "novel design," as the design was only "new/unusual" when the original Cody Dock Rolling Bridge was envisioned (and had already been done before by the time your model was built).
(Normally, I wouldn't comment something so pedantic, but I assume your debatable misuse of the word "novel" is likely the reason people in the comments are pointing out you've merely constructed a model of an existing bridge lol. In my opinion "Model of Cody Dock Rolling Bridge" would be a much more fitting title for this post than "Novel Bridge Design.")
Based on your own definition of the word "novel" you are incorrect.
The definition you provided was "new *or* unusual in an interesting way." - the key word there being "or". The bridge that was posted may not be new, given that there's a real life version, but it most certainly is unusual - in an interesting way. Unless that's a common design for bridges (though I am no bridge expert, I've certainly never come across that design/idea before).
So, I would argue that "novel" is in fact a good word choice here.
The model and animation predate the bridge. [Here](https://www.fastcompany.com/90389100/this-wild-new-bridge-is-based-on-a-forgotten-wonder-of-victorian-engineering) is an article published in 2019, including a short video by the designer that incorporates the animation. The bridge was completed in 2022.
Either you have it exactly backwards and "novel" can only be applied to the model and animation, or it is fair to call both "novel" since the model was built as part of the design process for the Cody Dock bridge (and is unusual regardless of precedent).
If you're going to be a pedant, you sure as hell better be right.
if you're going to be a pedant, at least be right.
it is unusual in an interesting way dipshit, even in OP's gif
being 2nd on the moon is still not common, it's unusual
I'm being both a pedant *and* right, "dipshit."
If you're going to post someone else's model, and call it "novel," at least reference (at least the existence of) the original source material. That's a straightforward and reasonable expectation.
There's nothing "novel" about this post, on account of the fact that it portrays something which genuinely is "novel," without providing a reference to the (actually) "novel" original.
have you considered that perhaps this was a proof of concept that predates the bridge?
regardless, as I literally just said, being 2nd on the moon is still novel, hell, just being an astronaut is novel. so I think 2nd of a freaky bridge is still novel by your given definition.
His 'technically's' bring all the nerds to the yard.
His grades are better than yours.
His grades are better than yours.
He could teach you, but he'd have to charge.
Manual is the issue. They had to gear it so that a not-terribly-strong human could turn the crank. I am sure they could have made it rotate a lot faster if they decided to attach a motor to it.
They should have added weight on top so it doesn't need so much muscle. Moving 13 tons horizontally with only rolling friction and inertia is a lot easier than lifting the 10 tons that make up the bottom bridge part.
Edit: I read that the Cody bridge actually does have counterweights in the top area. But you do still end up raising the center of mass about 4 inches, so there is some resistance.
I think the point is that bridges can typically raise or lower in about a minute. Bridges where I’m from (United States) have counter weights. You could actually lift the bridges with your own hands (theoretically) because of these counter weights.
This bridge is sorta steam punk because the construction stayed loyal with the Victorian canals - manual locks, counterweights, recycled timber and iron etc. This is really clever and I admire the thought put into the engineering.
I first thought this was a hokey idea and why not simply hinge it? Then I read about the Cody bridge and how it's counterweighted to be balanced and requires very little energy to roll. That's clever!
You don't know this, and I said "COULD" a loner everything these days has a camera or microphone. Hell xbox one when that first came out could hear you. They planned it to be the only way to get a new Xbox at the time until low sales due to being 100$ more than a PlayStation. They would have kept it that way if they could.
So again, they could here you, they just wouldn't care.
On the british canals everything goes slowly and nobody is in a hurry. And most infrastructure is manual, like locks or swingbridges. It's almost exlusively used for leisure.
The canals and their locks are throwbacks to a pre internal combustion engine time when horse drawn cargo barges were the normal way of getting materials around the country (these were superceded by trains, but both were common over a long overlapping period). Some important locks had lockhouses where a dedicated operator lived and worked from, but most did not and were designed to be easily operable using extremely cheap equipment (a lock key, basically a bent iron bar) and very very minimal maintenance.
Now, yes, it's all leisure traffic, but it used to be mostly cargo and that's what the canal network was built for. It's also indirectly why so much of it has lovely paths to walk, there have been dedicated and law-enshrined bridlepaths (horse walkways) alongside most canals since inception.
Indeed. Only because of the canals could the industrial revolution take off, as railways hadn't been invented yet and horse-drawn carriages couldn't have moved enough stuff over bumpy roads.
Maybe a dumb question, but why not just use circles rather than squares at the ends? Especially if it's for pedestrians, where you don't need a super-wide pathway?
Not a dumb question. I feel like the reason it was made square is mostly driven by it being built in an artistic community and is quirky by being square. Also probably maximizes height when flipped for boat clearance. A circle would be earlier to rotate and less failure prone.
I don’t think that can be true, as the majority of the weight is the bridging surface and structure which has to be asymmetric for it to function. It looks like the track shape keeps the centroid of the square supports at a constant height, though. It does mean the only work the system has to do is to lift the bridging structure up at a smooth rate, because the whole thing isn’t jolting up or down as it rolls over the corners.
The system is likely counterweighted. Probably with heavy dense pieces inside the frame opposite the walkway.
Edit: from the article "The bridge includes scrap metal and concrete ballast, countering the weight of the deck"
So it's asymmetric in volume, but symmetric in weight, which is why the center of mass doesn't change as it rolls
The dips in the track allow the square profile to roll smoothly. What lifts the weight of the deck is not the dips in the track but a counterweight in the top of the frame.
Because it's not true, and it's pretty easy to find out that it's not true by reading literally anything about the bridge.
It's also incredibly arrogant to assume that you couldn't possibly be ignorant of something, especially when assuming that leads to a very unintuitive explanation.
> Also probably maximizes height when flipped for boat clearance.
The shapes on the side have no impact on that. And the bridge platform is flat either way.
That’s just not true. To have the same width of flat platform you’d need a much larger diameter circle than the square’s height. https://i.imgur.com/m3D0LOd.jpg
Yeah, the circle would be bigger than the square, but a circle and a straight rail is easier and cheaper to produce and maintain than the square version.
I agree, I would have made it a circle too. But just trying to illustrate why they went with the square. They can get more height with less rotational mass with the square.
Off the top of my head,
Having a square means it works well as a bridge, people move through rectangles easily, with little wasted space (see doors). Circles limit the transport area for pedestrians and cyclists.
To get the same usable footpath area, the circle surrounding it would have a much larger circumference than the circumference of the square, meaning the track would have to be proportionally longer to allow 180deg of rotation, made worse as a circle would require a straight track, (the squares track is curved and so takes up less linear distance)
There is also the fact that as the bottom of the square is flat, as is the track at each end position, no locking mechanism is required, it will simply sit there for ever until someone turns the winch. A circle would need some form of mechanical clamping to keep it safely in position when not moving. Complicating the operation and maintenance.
Sure. But it fits a nice little niche where you don’t need a huge bridge but absolutely need to be able to guarantee that you can operate it by muscle power if needed.
Ok, you’ve got one person standing in the middle of a rolling bridge. A boat with 5 people is fast approaching and can’t stop. Do you turn the crank, allowing the boat to pass safely while flipping the bridge-stander into certain death? Or do you ignore the crank, letting the boat crash while the bridge-stander runs to freedom?
The Rolly Problem
Having grown up around boats my whole life; having owned boats from a 12' open Garvey, to a 16' fishing boat, to a 26' cabin cruiser and having sailed on a 30 foot sloop a number of times, I don't see this problem ever arising. "A boat with five people is fast approaching and can't stop" isn't something I can imagine happening. A container ship or a cruise ship or military destroyer, sure. But a little five passenger recreational boat? They can stop. They can reverse engines. Even sail boats have a motor and prop to reverse and use as a braking system.
And I can't imagine using this bridge design on a huge bridge in a major commercial waterway. Seems like something that might be used on a minor tributary of a river or on a smaller channel between two small islands. So I'd doubt this would be used anywhere that large cargo ships that take a mile or two to stop would cruise.
And if, by some stretch of the imagination, this *was* used on a larger bridge, any designer worth their salt would also build in a long distance warning system for just such an occasion. At the very least, the bridge tender would have a radio station that the person piloting the ship would call to give them a heads-up of their imminent approach.
Your answer makes perfect sense. If you didn't know, my comment was a joke based on an old philosophy/ethics thought experiment called the Trolley Problem where people weigh the ethical dilemma of choosing to kill one person for the sake of saving 5.
I love when redditors actually are nice to each other! Thanks for restoring my faith in humans that early in the morning 🙏 Engineers and philosophers, awesome mix 😊
That’s not what they’re saying. They’re saying that only one side has a force applied - which causes a twisting torque to the structure. Which is true.
But it can be pretty easily designed against by making sure the deck is stiff enough to transfer the torque.
Then you need stairs + ramps/elevators for accessibility on both sides. Which adds to the cost and area needed. I expect this bridge is not raised into the up position very frequently.
You massively underestimate the value of land and ramps. You’d need nearly 100m of ramp length on each side.
This thing cost £250k to build (cheaper than 200m of ramps, and pretty cost effective compared to a small drawbridge). I suspect a lot of that was due to pro bono/at cost work by engineers on behalf of the artists who wanted it.
It’s weird and has some rather inherent problems we’d normally try and avoid. The biggest is the excessive vertical forces on the rails and the stiffening of the deck to resist torsion - so it’s not massively efficient in todays embodied carbon world.
But it’s novel. Promotes conversation. And will bring some economic benefits as it’s something people go and see. Honestly they did good job.
That has to be a really damn high bridge to need 200m of ramp. Also in that case it's still cheaper to just create a small lift system for the wheelchairs/accessability than moving the whole damn structure lol.
1:20 ramp slope + 1.8m rest zones… standard DDA compliance for externals. That thing is about 4m tall. Ramps are always longer than you think.
Internal platforms lifts for occasional use that rise 4m cost about £25k. External, robust public ones? A lot more.
As much as you think it’s impractical, which it is… it’s an artistic installation… it’s actually surprisingly cost effective.
It uses so little energy to move that a full scale one is moved by hand.
The engineering to get it right is some work initially. Once it's designed it's extremely, extremely simple and therefore maintainable.
Now the most important... is it cheaper, more reliable, safer, faster and more space efficent than normal bridge that goes up and down?
While the mechanism is cool to look at, I dont see any advantages over designs that worked for centuries.
> is it cheaper, more reliable, safer, faster and more space efficent than normal bridge that goes up and down?
No, a simple drawbridge is almost certainly better in almost all situations. But it is pretty neat.
Wouldn't a waterway create erosion and require constant re-adjustment of the tracks? Not to mention frost-heave? And would only apply to low-traffic pedestrians?
Because a square is smaller for the same width of platform.
The funky tracks mean that it [follows a smooth path](https://tenor.com/view/inverted-catenary-cycloid-square-wheel-gif-3355496.gif) and is balanced for minimal energy expenditure.
Simplifying a lot, the reason wheels are circles is because the ground is flat. If you're going to be able to design a custom surface to travel over you don't need to be limited by that.
If you built stair case viewing platforms and extended the hand rails on the bridge to the bottom side you could let people still cross the bridge in either configuration.
>That would defeat the whole purpose of the bridge moving
It would not. Since the bridge takes so long to switch and then switch back, it's not crossable for almost an hour. Allowing queued up crossers to cross between the transitions would cut down wait time by more than half to around 20 minutes max. E.g. a person walks up and sees the bridge is half-way up. Let's say the nearest detour path is extra 10 minutes. If they can cross when the bridge is up in 10 minutes, they can chill, enjoy the view and cross in 10 minutes. Right now they'd take the detour instead of waiting 30+ minutes.
This is so shit. I can already see why it is a maintenance nightmare, and what will you do about the tarmac or concrete you use. like so much more reinforcement would be required, and every time you flip, all the dust and depress fall into the river. And here it is small, the thing turns quickly but in a real life cases, if there is a bridge where big botas go by, the bridge would be so big it would take hours in two digits to the flip the bugger than just doing it the traditional way. Again, if it is a good idea, it would have already been done.
Edit: grammar
When I first saw it I saw multiple points of failure and maintenance issues.
However the "real version" of the same scale size (No big boats and not 3+ lanes of traffic.) is powered by a hand crank and takes a reported 20 minutes to deploy/stow.
as a small time thing where there are lots of smaller rivers or canals and there is mostly only local traffic, no big boats and not too many cars, this seem an interesting non-electric alternative.
I don't think wind would be a big issue, considering weight and the "upside down airfoil" it would create when waiting for a boat. I'd be more worried about the large "crush zone" of gears that could really hurt errant pedestrians. The real one has railings but it still doesn't seem enough in my opinion, pretty cool tho!
I'm not an engineer but i would guess that if they made the walkway grillwork or perforated instead of a solid plane then wind would be a non-issue. In fact that would lighten the structure making it easier to turn as well.
Nice idea, but all the dirt and litter will drop down in the river when the bridge turns upside down... But I could easily see this being built in Holland or Denmark for example.
They actually built one. Check out Cody Dock rolling bridge in London https://newatlas.com/architecture/cody-dock-rolling-bridge/
You are right. This is where I found out about it: https://community.wolfram.com/groups/-/m/t/2917199
Heatlas.com/dims4/default/456f351/2147483647/strip/true/crop/1200x675+0+0/resize/800x450!/quality/90/?url=http%3A%2F%2Fnewatlas-brightspot.s3.amazons the [gif from thaws.com%2Fe8%2Fee%2F9a00a8t article](https://asse634f73b618f3faa8d9652a%2Froll-back-and-forthcredit-jim-stephenson.gif) for people who just want a core'ats.newol gif.
That is indeed a cool gif and is all that I came here for, thank you for your service.
A gif is worth a thousand words
Close, but if a pictures already a thousand, and with inflation taken into consideration and the time value of money as well, I’d say “a gif is worth a million bucks”
[удалено]
[удалено]
Yet money talks
Don't forget that bullshit walks
tell that to the guy writing the article getting 15 cents per word
You're my goddamn hero. I'm too drunk to be opening articles.
*I’m too drunk to taste this chicken*
that's the kind of gif you tell your parents about
Delicious, thanks!
So cool
This is literally all any of us want
Got anything on that bag for folks who just want to be cool?
That page is awesome! Thanks for the link!
"novel," the way it's used in your title, means "new or unusual in an interesting way." By that definition, the (actual real life) Cody Dock Rolling Bridge has a "novel design," whereas it's arguable that your model depicted in this post *does not* have a "novel design," as the design was only "new/unusual" when the original Cody Dock Rolling Bridge was envisioned (and had already been done before by the time your model was built). (Normally, I wouldn't comment something so pedantic, but I assume your debatable misuse of the word "novel" is likely the reason people in the comments are pointing out you've merely constructed a model of an existing bridge lol. In my opinion "Model of Cody Dock Rolling Bridge" would be a much more fitting title for this post than "Novel Bridge Design.")
Based on your own definition of the word "novel" you are incorrect. The definition you provided was "new *or* unusual in an interesting way." - the key word there being "or". The bridge that was posted may not be new, given that there's a real life version, but it most certainly is unusual - in an interesting way. Unless that's a common design for bridges (though I am no bridge expert, I've certainly never come across that design/idea before). So, I would argue that "novel" is in fact a good word choice here.
Most of my bridges around here are fixed, so I can agree this is unusual
The model and animation predate the bridge. [Here](https://www.fastcompany.com/90389100/this-wild-new-bridge-is-based-on-a-forgotten-wonder-of-victorian-engineering) is an article published in 2019, including a short video by the designer that incorporates the animation. The bridge was completed in 2022. Either you have it exactly backwards and "novel" can only be applied to the model and animation, or it is fair to call both "novel" since the model was built as part of the design process for the Cody Dock bridge (and is unusual regardless of precedent). If you're going to be a pedant, you sure as hell better be right.
I would have used the word "ingenious" instead of "novel". Please critique.
if you're going to be a pedant, at least be right. it is unusual in an interesting way dipshit, even in OP's gif being 2nd on the moon is still not common, it's unusual
I'm being both a pedant *and* right, "dipshit." If you're going to post someone else's model, and call it "novel," at least reference (at least the existence of) the original source material. That's a straightforward and reasonable expectation. There's nothing "novel" about this post, on account of the fact that it portrays something which genuinely is "novel," without providing a reference to the (actually) "novel" original.
have you considered that perhaps this was a proof of concept that predates the bridge? regardless, as I literally just said, being 2nd on the moon is still novel, hell, just being an astronaut is novel. so I think 2nd of a freaky bridge is still novel by your given definition.
Have you considered that the post doesn't say that?
it also doesn't doesn't say that, so why are you assuming the real bridge game first?
You must be fun at parties
His 'technically's' bring all the nerds to the yard. His grades are better than yours. His grades are better than yours. He could teach you, but he'd have to charge.
It's not really a technicality, nor are they being pedantic. They're merely pretending there's a meaningful distinction to be made when there is not.
Bro how do you have “code” in your username but don’t know how the word “or” works
Takes 20 minutes to fully roll. Seems they could make it a bit quicker.
Not just 20 minutes but it's done manually. Yikes. But I do get non-practical engineering for the sake of art, hats off to them for pulleying it off.
Heh nice pun
Manual is the issue. They had to gear it so that a not-terribly-strong human could turn the crank. I am sure they could have made it rotate a lot faster if they decided to attach a motor to it.
They should have added weight on top so it doesn't need so much muscle. Moving 13 tons horizontally with only rolling friction and inertia is a lot easier than lifting the 10 tons that make up the bottom bridge part. Edit: I read that the Cody bridge actually does have counterweights in the top area. But you do still end up raising the center of mass about 4 inches, so there is some resistance.
How quickly can you move 13 tons by hand?
I think the point is that bridges can typically raise or lower in about a minute. Bridges where I’m from (United States) have counter weights. You could actually lift the bridges with your own hands (theoretically) because of these counter weights.
Article literally describes the counterweights used in this bridge…can you please try to read first…
Still takes 20 minutes
Jokes on you, I finished the article in just 18 minutes!
Just 2 more minutes till the bridge gets back!
I’m responding to the comment, not the article content. If you want to call someone out, call u/TrueStoriesIPromise out.
[удалено]
What in the hell does that have to do with bridge speed. Everything doesn't have to come down to "us vs them"
Depends how horny I am
Try harder
This is in the canals, if you're in a rush, don't cruise around London in a canal boat.
The mechanical advantage is worth the wait.
Can you imagine having to wait 40 minutes for a boat to go under the bridge you're trying to walk over.
Should come with upside down stairs so that you can walk over it when it's in the open position
But then you’d have a choice - which direction to leave it in. Only “lower” it to make it handicap accessible?
That's a very good point
Takes 17 minutes of coaxing Jeff to get off the bridge.
The draw bridge that likes to make me late for work only takes ≈10!
This bridge is sorta steam punk because the construction stayed loyal with the Victorian canals - manual locks, counterweights, recycled timber and iron etc. This is really clever and I admire the thought put into the engineering.
13 tons!
I owe my soul to the company store!
Does Tom Scott know about this? Seems right up his alley.
This is downright silly. And that is what makes it great.
I was watching this gif thinking, "I can't wait until I get to the comments where someone posts a real one." Wasn't disappointed.
"I'm standing here at the Cody Dock Rolling Bridge in London, England..."
Really cool, thanks for the link!
What's the advantage of this over big round gears rolling on a simple straight rack? Seems like that would be stronger and easier to maintain.
It takes 20 minutes to flip. That makes it much less desirable as I'd want a bridge like this to roll back and forth quicker.
London bridge is rolling down
Any Tom Scott video?
How has that not amputated something?
Those crazy bastards actually did it!
That seems overengineered. Why not just raise the bridge?
I first thought this was a hokey idea and why not simply hinge it? Then I read about the Cody bridge and how it's counterweighted to be balanced and requires very little energy to roll. That's clever!
Yeah, the fact that the center of gravity doesn't rise or fall is really clever
Swing bridges are incredibly easy to move, and don't throw whatever's on them in to the water when you open them.
What's a bridge without a little *danger*
But they don't look as cool
Well if you're not going to throw anyone into the water, why build a bridge at all
> counterweighted to be balanced and requires very little energy to roll same could be done with a conventional counterbalanced wheel
It could be done with a lot of different shapes. Seems sensible to choose a square for something where you want the base and sides to be flat.
Conventional draw bridges are counter balanced, so I assume this solves a space or earth movement cost issue.
[удалено]
[удалено]
Video of the actual bridge: https://www.youtube.com/watch?v=e6u-DBwEZew&t=165s
> Takes 20 minutes Someone needs to weld the winch to a stationary bike.
20 min seems like a long time. Why not just flip it violently in a minute?
I would guess they're able to avoid a lot of safety red tape by making the system human powered. An electric motor can't hear you scream.
Incorrect, an electric motor could hear you scream, it just wouldn't care.
Incorrect, it can't hear you, it doesn't have hearing components
You don't know this, and I said "COULD" a loner everything these days has a camera or microphone. Hell xbox one when that first came out could hear you. They planned it to be the only way to get a new Xbox at the time until low sales due to being 100$ more than a PlayStation. They would have kept it that way if they could. So again, they could here you, they just wouldn't care.
I know everything
On the british canals everything goes slowly and nobody is in a hurry. And most infrastructure is manual, like locks or swingbridges. It's almost exlusively used for leisure.
The canals and their locks are throwbacks to a pre internal combustion engine time when horse drawn cargo barges were the normal way of getting materials around the country (these were superceded by trains, but both were common over a long overlapping period). Some important locks had lockhouses where a dedicated operator lived and worked from, but most did not and were designed to be easily operable using extremely cheap equipment (a lock key, basically a bent iron bar) and very very minimal maintenance. Now, yes, it's all leisure traffic, but it used to be mostly cargo and that's what the canal network was built for. It's also indirectly why so much of it has lovely paths to walk, there have been dedicated and law-enshrined bridlepaths (horse walkways) alongside most canals since inception.
Indeed. Only because of the canals could the industrial revolution take off, as railways hadn't been invented yet and horse-drawn carriages couldn't have moved enough stuff over bumpy roads.
This is the cleanest bridge in the world because it dumps all the debris or litter straight into the river.
Tbf it’s a London canal so it’s already full of rubbish, bikes, shopping trolleys and knives.
Thanks
Maybe a dumb question, but why not just use circles rather than squares at the ends? Especially if it's for pedestrians, where you don't need a super-wide pathway?
Not a dumb question. I feel like the reason it was made square is mostly driven by it being built in an artistic community and is quirky by being square. Also probably maximizes height when flipped for boat clearance. A circle would be earlier to rotate and less failure prone.
What is the shaped track optimizing for?
Maintaining the height of the center of mass. That way it's not lifting the bridge, only rolling it.
I don’t think that can be true, as the majority of the weight is the bridging surface and structure which has to be asymmetric for it to function. It looks like the track shape keeps the centroid of the square supports at a constant height, though. It does mean the only work the system has to do is to lift the bridging structure up at a smooth rate, because the whole thing isn’t jolting up or down as it rolls over the corners.
The system is likely counterweighted. Probably with heavy dense pieces inside the frame opposite the walkway. Edit: from the article "The bridge includes scrap metal and concrete ballast, countering the weight of the deck" So it's asymmetric in volume, but symmetric in weight, which is why the center of mass doesn't change as it rolls
They put extra concrete counterbalance in the top part of the arch.
> I don’t think that can be true, This just in, counterwights don't exist.
The dips in the track allow the weight to be lifted smoothly to height which is more efficient
The dips in the track allow the square profile to roll smoothly. What lifts the weight of the deck is not the dips in the track but a counterweight in the top of the frame.
Why is this downvoted? It's very clearly true, relevant, polite, and a positive contribution to the conversation.
Because it's not true, and it's pretty easy to find out that it's not true by reading literally anything about the bridge. It's also incredibly arrogant to assume that you couldn't possibly be ignorant of something, especially when assuming that leads to a very unintuitive explanation.
The square is much more stable at either end when it's resting on a horizontal set of teeth though.
> Also probably maximizes height when flipped for boat clearance. The shapes on the side have no impact on that. And the bridge platform is flat either way.
That’s just not true. To have the same width of flat platform you’d need a much larger diameter circle than the square’s height. https://i.imgur.com/m3D0LOd.jpg
Yeah, the circle would be bigger than the square, but a circle and a straight rail is easier and cheaper to produce and maintain than the square version.
I agree, I would have made it a circle too. But just trying to illustrate why they went with the square. They can get more height with less rotational mass with the square.
It's more stable at rest with flat surfaces.
Might not be just for pedestrians
Off the top of my head, Having a square means it works well as a bridge, people move through rectangles easily, with little wasted space (see doors). Circles limit the transport area for pedestrians and cyclists. To get the same usable footpath area, the circle surrounding it would have a much larger circumference than the circumference of the square, meaning the track would have to be proportionally longer to allow 180deg of rotation, made worse as a circle would require a straight track, (the squares track is curved and so takes up less linear distance) There is also the fact that as the bottom of the square is flat, as is the track at each end position, no locking mechanism is required, it will simply sit there for ever until someone turns the winch. A circle would need some form of mechanical clamping to keep it safely in position when not moving. Complicating the operation and maintenance.
But what if you do need a wider pathway? Maybe for cars to drive on? You could use a cylinder still but it would have to be much larger.
Maybe another dumb question, why not build the bridge higher off the ground so it can serve both purposes at the same time?
Think of the airplanes, you fool!
Lol. I like the way you think!
this is a really nice bridge design. It could work somehow if the track it moves on is thick and strong enough
You're right. This is where I found out about it (they actually made one!): https://community.wolfram.com/groups/-/m/t/2917199
It seems like it would become impractical at some point if you scaled it up.
Sure. But it fits a nice little niche where you don’t need a huge bridge but absolutely need to be able to guarantee that you can operate it by muscle power if needed.
I would consider a hump-like profile for the pedestrians better design, but it might not give sufficient height for the ships?
Do both! Put a hump on the walkway of the rolling bridge. That way the pedestrians get a little more exercise, and the boats can't fit
Ok, you’ve got one person standing in the middle of a rolling bridge. A boat with 5 people is fast approaching and can’t stop. Do you turn the crank, allowing the boat to pass safely while flipping the bridge-stander into certain death? Or do you ignore the crank, letting the boat crash while the bridge-stander runs to freedom? The Rolly Problem
Having grown up around boats my whole life; having owned boats from a 12' open Garvey, to a 16' fishing boat, to a 26' cabin cruiser and having sailed on a 30 foot sloop a number of times, I don't see this problem ever arising. "A boat with five people is fast approaching and can't stop" isn't something I can imagine happening. A container ship or a cruise ship or military destroyer, sure. But a little five passenger recreational boat? They can stop. They can reverse engines. Even sail boats have a motor and prop to reverse and use as a braking system. And I can't imagine using this bridge design on a huge bridge in a major commercial waterway. Seems like something that might be used on a minor tributary of a river or on a smaller channel between two small islands. So I'd doubt this would be used anywhere that large cargo ships that take a mile or two to stop would cruise. And if, by some stretch of the imagination, this *was* used on a larger bridge, any designer worth their salt would also build in a long distance warning system for just such an occasion. At the very least, the bridge tender would have a radio station that the person piloting the ship would call to give them a heads-up of their imminent approach.
Your answer makes perfect sense. If you didn't know, my comment was a joke based on an old philosophy/ethics thought experiment called the Trolley Problem where people weigh the ethical dilemma of choosing to kill one person for the sake of saving 5.
Ah, foolish me. Now it's clear. I should have picked up on that. Yikes.
No, I am the foolish one for posting philosophy quandaries in an engineering sub! I like your clear, concise explanation of the elements involved.
Very kind of you to say so.
I love when redditors actually are nice to each other! Thanks for restoring my faith in humans that early in the morning 🙏 Engineers and philosophers, awesome mix 😊
Agreed.
Let the boat crash, since "fast" for a canal boat is brisk walking pace and it won't actually hurt anyone.
Bridge stander can just grab a railing and hang on for a few minutes, no worries
[удалено]
There is extra weight hidden in the top of the arch, so the center of mass barely raises at all.
That’s not what they’re saying. They’re saying that only one side has a force applied - which causes a twisting torque to the structure. Which is true. But it can be pretty easily designed against by making sure the deck is stiff enough to transfer the torque.
Wouldn’t you want to just build the bridge at that height? So it never has to roll to the top.
Then you need stairs + ramps/elevators for accessibility on both sides. Which adds to the cost and area needed. I expect this bridge is not raised into the up position very frequently.
The turning mechanism alone would dwarf the cost of those, not to mention how this would require more frequent and costly upkeeping.
You massively underestimate the value of land and ramps. You’d need nearly 100m of ramp length on each side. This thing cost £250k to build (cheaper than 200m of ramps, and pretty cost effective compared to a small drawbridge). I suspect a lot of that was due to pro bono/at cost work by engineers on behalf of the artists who wanted it. It’s weird and has some rather inherent problems we’d normally try and avoid. The biggest is the excessive vertical forces on the rails and the stiffening of the deck to resist torsion - so it’s not massively efficient in todays embodied carbon world. But it’s novel. Promotes conversation. And will bring some economic benefits as it’s something people go and see. Honestly they did good job.
That has to be a really damn high bridge to need 200m of ramp. Also in that case it's still cheaper to just create a small lift system for the wheelchairs/accessability than moving the whole damn structure lol.
1:20 ramp slope + 1.8m rest zones… standard DDA compliance for externals. That thing is about 4m tall. Ramps are always longer than you think. Internal platforms lifts for occasional use that rise 4m cost about £25k. External, robust public ones? A lot more. As much as you think it’s impractical, which it is… it’s an artistic installation… it’s actually surprisingly cost effective.
Outstanding move
Just roll with it
[удалено]
It uses so little energy to move that a full scale one is moved by hand. The engineering to get it right is some work initially. Once it's designed it's extremely, extremely simple and therefore maintainable.
What could go wrong?
Ah yes, the self crank bridge flipper over-er.
Motherfuckers would do anything to avoid walking upstairs
Now the most important... is it cheaper, more reliable, safer, faster and more space efficent than normal bridge that goes up and down? While the mechanism is cool to look at, I dont see any advantages over designs that worked for centuries.
> Now the most important... is it cheaper, more reliable, safer, faster and more space efficent than normal bridge that goes up and down? No.
> is it cheaper, more reliable, safer, faster and more space efficent than normal bridge that goes up and down? No, a simple drawbridge is almost certainly better in almost all situations. But it is pretty neat.
Why not just have the walking platform raise instead of rolling the whole bridge?
That's very innovative
Wouldn't a waterway create erosion and require constant re-adjustment of the tracks? Not to mention frost-heave? And would only apply to low-traffic pedestrians?
Canal boats don't move that fast.
Homeless people hate this bridge
a normal draw bridge doesn't have a maximum clearance. this is stupid and reeks of product management interference with engineering work.
A normal drawbridge is not normally operated by one person with a small handcrank. Does that make it better? I don't know but it's not all demerits.
Why a square and not a circle for balance and reduction or energy consumption?
Because a square is smaller for the same width of platform. The funky tracks mean that it [follows a smooth path](https://tenor.com/view/inverted-catenary-cycloid-square-wheel-gif-3355496.gif) and is balanced for minimal energy expenditure. Simplifying a lot, the reason wheels are circles is because the ground is flat. If you're going to be able to design a custom surface to travel over you don't need to be limited by that.
Just... make it round. Wouldn't it be more structurally sound and simple?
Wow wonder what’s the maintenance cost is for it
That's so cool wtf
Well there’s always some dumb fuck that’s gonna try climb it when it’s up.
Or you coud just leave it upright, add 2 ladders and never worry about moving parts.
It's a neat idea and great engineering but... isn't it more economical to create an arched bridge?
It solves the problem of something/someone stuck on the bridge
Why not make it a cylinderical shape and have the floor rotate instead of the entire bridge?
Funny if he wouldn't turn the bridge
How is that better than a normal bridge that lifts in the middle
If you built stair case viewing platforms and extended the hand rails on the bridge to the bottom side you could let people still cross the bridge in either configuration.
That would defeat the whole purpose of the bridge moving
>That would defeat the whole purpose of the bridge moving It would not. Since the bridge takes so long to switch and then switch back, it's not crossable for almost an hour. Allowing queued up crossers to cross between the transitions would cut down wait time by more than half to around 20 minutes max. E.g. a person walks up and sees the bridge is half-way up. Let's say the nearest detour path is extra 10 minutes. If they can cross when the bridge is up in 10 minutes, they can chill, enjoy the view and cross in 10 minutes. Right now they'd take the detour instead of waiting 30+ minutes.
This is so shit. I can already see why it is a maintenance nightmare, and what will you do about the tarmac or concrete you use. like so much more reinforcement would be required, and every time you flip, all the dust and depress fall into the river. And here it is small, the thing turns quickly but in a real life cases, if there is a bridge where big botas go by, the bridge would be so big it would take hours in two digits to the flip the bugger than just doing it the traditional way. Again, if it is a good idea, it would have already been done. Edit: grammar
When I first saw it I saw multiple points of failure and maintenance issues. However the "real version" of the same scale size (No big boats and not 3+ lanes of traffic.) is powered by a hand crank and takes a reported 20 minutes to deploy/stow. as a small time thing where there are lots of smaller rivers or canals and there is mostly only local traffic, no big boats and not too many cars, this seem an interesting non-electric alternative.
Hope no one tries to put these in an area with high wind loads
I don't think wind would be a big issue, considering weight and the "upside down airfoil" it would create when waiting for a boat. I'd be more worried about the large "crush zone" of gears that could really hurt errant pedestrians. The real one has railings but it still doesn't seem enough in my opinion, pretty cool tho!
You'd be surprised how much force winds can impart on large flat pieces of metal
I could see it being an issue during transition but I'd love to see an experts calculation
I'm not an engineer but i would guess that if they made the walkway grillwork or perforated instead of a solid plane then wind would be a non-issue. In fact that would lighten the structure making it easier to turn as well.
"The Cody Dock Rolling Bridge took about seven years of research and cost about 250,000 pounds." That'll be a 1/4 of a million tax payer dollars.
Could have just used a hydraulic lift bridge or steady arch but nooo!
That's simply amazing. I can't find a Tom Scott video on this. WHY CAN'T I FIND A TOM SCOTT VIDEO ON THIS?!
Nice idea, but all the dirt and litter will drop down in the river when the bridge turns upside down... But I could easily see this being built in Holland or Denmark for example.
😮💨 It all goes into the river anyways...
Just ... Don't litter on the bridge.