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SYSK Selects: Bridges: Nature Abhors Them

2021-02-27 | 🔗

From prehistoric logs across streams to the 102-mile Kunshan Grand Bridge, nature works ceaselessly to take down spans. In this classic episode, learn about the fascinating ins and outs of bridge design and building and the mind-boggling challenges structural engineers face.

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With no fees or minimums on checking and savings accounts banking with capital. One is like the easiest decision in the history of decisions, unlike choosing to listen to another episode of your favorite broadcast and with their top rated app. You can deposit checks in two for money anytime anywhere, making capital one and even easier decision. That's banking, re imagined. What's in your wallet term supply capital, one in a member at the icy hello, ass, white, Ass K, Pham its Josh and for this week's stuff you should know, selects I'd chosen bridges. Nature abhors them, which we released back in June of two thousand fifteen and it's a pretty good one. It's got a lotta engineering, believe it or not, but it's not like the eye lazy kind. It's like the almighty This is amazingly fascinating kind. I hope you feel that way at least and I'll bet you will so enjoy bridges nature
pours them. Starting now welcome to stop. You should know a production of Iheart Radio walk into the bargain Josh clogged with Charles the reach a bright with Jerry rolling with me just Clark. Instead, we should know Dietrich, Josh Clark, I'd say you never introduce yourself a mini than did it twice three three times Oh yeah, you always introduce real, but you never singer lessening extra No, I say I'm just Clark every time I should listen that they. Sometimes that explains the is overlooked in your eyes, whenever we start
Birds do yeah that your enter I like em. Maybe we can like a scam drummer. On top of that, we have that kind of a man we're doing listener. Meal is little better deemed earlier. The walesa sketch out it is more of a shovel sketch, like put Bob I bet you should get Hodgman diskette for you some time ago, but he's gonna get a lot of boot, reduce goldmine when he scan Jes hands. Now it's not exactly Manhattan transfer level. He's media, yeah, yeah, so again, bridges, yeah, now that we're gonna hear from some folks, because there are bridge enthusiasts yeah, which I think is kind of
There are members like modern marvels of engineering and actually there, some ancient marvels of engineering to. As far as through that, you say that they are yet there. If you basically, I was talking to our power Adam the architect of the bridge builder. Now he's a building building or a building designer I've actually knows how to build the bill. Is he does knows how to tell people how to Beth Avenant Adam cancelling a hammer. He was saying, Madame DE basically those structural engineers who design bridges are two straight up geniuses. I'm sure IKEA requires a basically genius to factor in all the stuff if anyone can design a building in four walls and bunch floors right, but a roof on it bridge so different,
aren't walls really there can be bridges, Madison County, they had walls, oh yeah, I have all. I was going to mention the bridges of Medicine County yeah. I love those that that be a beam bridge. I guess there what they are a truss right, atop dress was the doktor S, come through truss yeah through dress and an below that if it were but low, be a deck trust, but I don't know if they catch the trusted more. This, like a house on top of the bridge, I bet they're structural support, their gas NATO's meant mainly just to keep the rain offer you when you cross the bridge existent actual. Thank you for crossing the bridge. I thought it was just to draw an lackey. Tourists knew were wanted to add their picture made another famous bridge, the one that the headless horseman couldn't crossing the legend sleepy hollow.
oh yeah, and when that abridge sure trolls of under bridges that drawbridges are pretty cool heresy maxim overdrive the beginning of that movie it's been many many years I saw again babies. I saw it again very recently, like this year immediately, it may be better. There was before it holds up as a crappy movies, so yeah yeah a whole soundtrack. His ac Deasey, by the way, you should love all sound tried, do love there. You remember that and didn't Stephen King direct that yet, which he doesn't do much right now they may be, is only one is definitely first interesting, but there's a great drop. It drawbridge seen in there. I did some one jump. It jumped the span as it raised. No, I think their car feller the truck Phelan Elk and cause usually the drawbridge Siena's like I can make. It know this one was Europe,
doomed here behind the theme gotcha and let me also recommend Budapest for bridges. You mean I went over the past couple of years ago, what they're like twenty years ago? Okay, so yeah no bridges are amazing. Then I think, like five, because it an extra two sides Buddha impassioned right and each one is totally different, like it just a completely different design, yeah and they're, just all gorgeous yeah, Let's start with a bunch of bridge recommendations on going to recommend the city of Pittsburgh. Oh yeah, we base our aim there in usages gorgeous those beautiful bridges that you can see from the baseball stadium. and the river. Those one were slightly a toilet, a commercial trying right here. I stayed in the hotel in just a sob penny. Now chicken saga right just like a quarter
but he could see the baseball say to him out you're out a window near, and I saw some bridges to you: walk across the bridge to get their right released, weeded what us, neither bridges, Brow, Brooklyn Bridge churn gone gay bridge. Yes, it like the famous ones, are barely even worth mentioning yeah, but the Brooklyn Bridges for your money. It's which is free. It's a pretty great thing to do the walk across at its core. Its dispute with I've never done that they should do it. Even the Geico Lizard did it and I haven't like guys like Australian or something, but maybe we should just animate you have you walk across it? One more thing. If you want to know more about the Brooklyn Bridge, I dont her, which, when we talked about it, but there is a really cool documentary about the Brooklyn Bridge in its building up, I can burns. Oh, I believe it son Netflix, at the check that out there like can burns in Brooklyn Bridges
Are you ready, yeah man? So bridges have been around for a very long time. This the goal is by Robert Lamb and another dude, nay Michael Morrissey. Together heavily, they were locked away in a closet for like a couple of months, while they work this out together,
I hate that one of the first ones to turn my ancient bridges that they mention, and here the arc de GO bridge in ancient Greece. Did you see that thing no drilling eat? I mean that it still stands at three thousand year old Bridge and is just kind of cool to think about. You know ancient civilizations and ancient times people said well. I want to get over there right and I'm here yet, and so let's build something to do that. I need some new walk on or drive my card over its at simple. I saw that I saw the world's oldest bridge that still in use is in Turkey over the Miller S River, a belief from eight fifty BC, Dino down Sir, how its constructed it is easy to see how it is a single stone, slab arch. No, it is a stone slab single arch.
That makes it very basic yeah, but the arch, its super old, but it's still in use today earlier, because whoever figured it out came upon this very elegant solution to a lot of problems that abridge poses because, as you were saying when, when you come on like a river or creek or something you say, I'm on this side and I need to be on the other side. So I need something to walk across and it's a basic solution, but the further and further you get the more more problems like his bridge builders, say most span MO problems yeah. I guess what we should have said as I want to walk across and live. I want I walked all the way across that right. I don't want to fall down that want to get halfway across and have it snap right so over the years as people have come upon problems. Where are you
are going to build a bridge that well snapping and kill you. They have come up with solutions to prevent that from happening, but that's pretty much. The pursuit of bridge building is coming up with wasted. a bridge from collapsing yet and a lot of trial and error the ears and a lot of real significant disasters. In fact, there's a time magazine slide, show called worst bridge collapses in past one hundred years, and it's got all these photos of key bridges and little descriptions and the number of fatalities and everything, but am it's? It's really interesting all these different bridges of collapsed and failed for all these different reasons: law and after each one. It's very sad, of course, but after each one someone goes o. While we should do this for the next one right. We should not forget that bolt next time, while this that could be human error to that's happy, I'm sure, are
So should we start off with the bats media? Be eighty s beams, arches, tresses and suspensions are the main components of structural components of a bridge. Three simple boom. That's it! That's all! You need to construct your own rights and with it As for things, you can make almost any kind of bridge organ cover mainly beam averages, arch bridges, trust bridges, suspension, bridges and then they supercool, looking cable stayed bridge is supercool Kampala. My favorite, looking bridge in the world that I came across a richer, researching, misses a cable stayed bridge the one that's in the article, oh yeah, they built, like you, click sales gorgeous the big triangles rising up its lovely yet, but it they look. A little more modern to me, their own tat that classic architectural, like the Brooklyn Bridge, does you're like the tower
London yeah? I think that's why I like it here. You, like the modern look here, your mind, guy, I'm supermodel our eye point out in the article, which is very key. What you talked about the span of the bridge is the distance between the supports and that's where that's where it all goes down. Basically, yes, that's gotta be strong there. Those are something that every single bridge has as a spam and at least one support most likely to yet and there's different the reason that there are different types of bridges, because different bridge designs that that bats designs. What is it beams, arches, trusses and suspension? They provide stability for very in span lengths. Yes, I like a beam if you have like a fifty foot span, just put a like A very long walk over over
spanning there you go. There's you breathe you. How did you get further along, you have more more problems supporting that span, so you need different types of solutions in the different length of span, calls usually for a specific type of bridge design, yeah and generally it it'll thing. There's a lot of overlap, of course, but being bridges tend to be the shortest followed by arch bridges and then suspension bridge is right and I think those on the cable stayed bridges is kind of a suspension bridge that counts. Yes, like him come a variation of late, they can be
belong as well, not quite as long as suspension bridge is, though, from what I understand unless the suspension bridge affords the longest span. Ok, to get a big long span its suspension time here and there also super expensive. Yes, suspension bridge is because all the bridge pillars know that you can log span that you're trying to cross you Polly gets in deep pockets and they're gonna milk you for earlier. Every penny, like you, need a suspension bridge, I'm your get yet aright. So let's talk about there a lot of different forces. It can act. on a bridge to make it not a stable will cover a few, the other ones later, but the main too here early on our attention and compression and the very easy way to think about these two things is tension is like if you you and I are pulling a rope yarn one in it, I'm on the other. We can pull that sucker, tight and
I'm gonna fall over due to your massive strength. I'm pretty huge bucks There will be some tension in that rope yet tenant, between us. Is the FDA fall down here and I'd start laughing. There would be tensions. Your attention is the lengthening of something yet compression is the shortening of something like a spring collapsed, So it's easy to visualize when you talkin like springs and ropes, and that kind of thing, but if you're talking about just a single deck of a bridge which you think of as one piece it's tough to it, it starts to get tough to visualize it.
Until you realize that you have to look at like a bridge deck roadway on the bridge year as really having a top and bottom yes and forces, while the compression acts in the downward motion on the top and the tension ex from underneath coming up on the bottom right. So the bottom of the bridge, underneath it of the deck is, is going to be spread out under the force of tension were on top, where the. being pushed down compressed. That's compression, Yannick kind of in a weird way, work together, even though that sort of opposite things there definitely related.
and what will happen as if these, if, if you are a very good bridge builder buckling will occur when its compressed on the top and snapping can occur on the bottom. When tension is at work, that's right now seems very confusing, but if you just do as like, but your hand outlook, right and so or if you take and pushed down in your hands on your hand, right aims in shit like that you're, like that, the the thing becomes very, very evident when you look at Cambridge, the most basic form of a bridge check if you dropped a log of a river in this. This thing of this article use the example of like taking a pair of milk crates and holding like a two by four across them right. Let's do that but like a bowling ball on a bowling, ball stand, so it doesn't role around me I'll, be out on top
the on top right in the middle of the year to buy for which makes up your beam bridge Deng right, you're gonna, see that it be rose, and what you're seeing is that on the top is being compressed on the bottom. Its being m test right in what you just done is at a load to that bridge and there's two kinds allows the start out: there's a dead load which is the weight of the bridge and all of its material combined, yeah and then there's alive load, witches say like the cars and the people in the trains and everything that that add the extra weight while they're moving across it. Everything and, as you add, this extra load, first of all, the bridge is already dealing with its dead load. You got that up! That's job number one fur bridge like if you had a three hundred foot to buy for and tumult creates, is gonna sag. it'll, just naturally right and it might even break, and there have been bridges that have been built that where the guy for it
The carry the one or whatever and they couldn't stand up under their own weight in collapse from their own way. They collapse from the dead load. So job number one of the bridges to support its own weight. Job numbered one point: one is to support all of the live load, the traffic that goes across it as well that right and the two that you're gonna. Do this to counteract tension in compression, are dissipation and transference force yeah transferring the forces with dissipation. You spread, out that force equally spread out over a wide area and with transfer
and you move the area of weakness to an area of strength right which pretty simple, yet they're kind of tough to distinguish. Sometimes you know me, but, for example like at the best example of dissipation is the arch which will talk about how that works in a second year, but suspension bridges are best at transferring the tension in russian forces that right. So, if you're it. If you're talking about a Bainbridge that most basic kind, the other thing they're gonna do to make it stronger of courses use back in the old days. He is worth Then later iron and then steel right be some concrete mix. Ten, but the size of the beam is going to be really important, like the height of the beam is important. Cuz, the the top is going to experience stress. The bottom is going to experience stress in the middle, not as much
so good, IBM right, a guitar IBM is what you want and I didn't realize it. That's why I beams or made like I beheaded. Really, there is maybe garlic sent to the centre of like the decker, the Beemer, whatever any kind of being is going to experience. The least amount of compression attention is really the top or the bottom here, so you don't put quite as much material into the centre. The beam as you do, the top and bottom to prevent heckling and snapping. That's right. So the beam bridge, you're gonna, add, what's called a truss to make it stronger This will talk about trusses more, but it's basically triangulated strength and you'll see. Thus, if you ve ever seen like a the train bridge. Like you, you see a truss on top or the like in areas where they get alot of snow roof supports. Who frequently be true, yeah, and that's it through dress. On top, we already said, and if its underneath then
is the deck trusts right and you cannot both but usually like with the railroads you'll, see like that top truss not seems a trestle different right. It's like a roller coaster. In a sort of this break, We talk more about transport is nice. you know me undies believes that on these aren't just what you put under your clothes, they believe and these are the most important layer yeah that later should filling a second skin but better which allows you to feel like That's right and I gotta tell ya building your collection of soft as all get out. Undies has never been easier because they ve created a membership. We get a pair of your favorite undies, delivered every single month
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the regional film, my mom taught me how to write funds. My dad Tommy play the piano and I still make music and my brothers bedroom, but I'm the back of the sick visa every somewhere. You guys, I'm nobody had gone away like me. When I tell you I wish the world would have worry streaming, possibly Apple tv plus rated. I didn't
so Chuck, no joke tresses are one of my favorite things. Now it's pretty need. After doing some research into I'm, like I love trusses, your Truscott yeah, it's because they're so elegant in simple, there elegantly simple, basically it so. I saw this really great explanation where I was Unmake magazine and I think it's called like. I ask make. How do trust his work pretty straightforward and it basically had like I'm really gave a great graphic of. Taking part using popsicle sticks right. Ok, let's say you make a square out. Popsicle stakes in you join the the popsicle sticks together at the corners, where the ends all meet yet little elmers paste, maybe makes sense, seems pretty, is supportive right, but
when you press down on any one of those joints which is worth the loads going to be centred redistributed, most member that ends it did this square. the shift to the side known so never rhombus well ramesses, apparently less structurally sound, then a square. Yes, why? You very rarely see ramesses in architecture right right. With a triangle when you press down at any one of the joints, it distributes that compression retention directly through the center of the bean dear. So the triangle stay totally rigid, and when you add the more triangles you add the more support you had so they're like basically legs as far as a shape goes the superconductor of transferring or distributing compression or tension.
Yeah, that's good when you put it and that's why, when you'd see that that trainer trestle on that has a truss on top and got all those beautiful diagonal pieces of metal right and it's not just for four looks even though it is cool, No one of the other great things about a trust is that their you know it's like just the three steel beams or three whatever aluminum beams, they're, just three pieces of metal usually fixed together, and that's that's the other key that I left out. They were, they have to be connected at the ends equally distributed from each right. So let's say you'd you draw hold the terrific one side of the trust to another one under the trust to another and that the other and has to be equally far away right. Do you see what I'm saying yeah they wouldn't be a God drove out alone. Wherever sir anyway, you have to add that the place where the tress side,
join together, has to be on the UN's yet and then, but one of the thing that it allows for is for wind blowing it is a sure. That's a huge point about tresses they're, not solid in that their they don't they dont prudent, put up a lot of resistance to when they How to float through, which is really kind of what you want will see when you're building bridges yeah, I think he's in the covered bridges- have is more of a lattice type thing on the side right. Yes, it's not solid, as it would be dumb a covered bridge,
yeah. I guess so. I thought the walls regionally like a lattice, so when could better now than they had it, that roof and like a ladder sea side is there. I am maybe there's all kinds near. I think those are just to keep the reign of oh yeah, that's what you said earlier and keep shooting down the year. The theory of suggestions have anyway, just as rock, I guess his worm trying to say. Yes, there's your t, shirt, trusses rock so are we urge is. Do we say that they frequently used trusses to support beam bridges, yeah, ok, arches! Now, when we say the bridge is an arch bridge, the deck is not some big hill that you drive over the deck is flat the arches underneath right now, and you can have a say
Arch, if your Spanish, along or you can have a big one with like six or eight arches, although I've seen, I think there are like short arch bridges that actually do go up and down. Oh sure, you know like a fairly in their natural Marge bridges like rock formations out like that. That's why they're still standing there is some there's there's a bridge that forms like a perfect circle. Like when, when you see reflected in the water, just looks like a circle. Nita many arch bridges are pretty cool to their no trusses, but they're beautiful, in their own way? Mr said arches, obviously semicircular, unlike you said, if it meets the water, reflects nicely Foley Circular wholly circle and the entire form is gonna, divert wait onto what are called abutments, and this is what takes on the pressure it's like I mean if it's just a single urge. Those abutments are probably gonna, be part of the earth.
on one side or the other yeah and the whole point of a button is when you press them. An arch or when you know, gravity pushes down on it or its compressed. That force goes downward and it makes the sides of the arch go out yet those abutments press inward, so that the force of compression discos straight down through the arch circle, the semicircle here the earth her into the ground or whatever yen, and it's the arch that what I thought was interesting. It's really! how about fighting that compression. There isn't a lot of attention that comes into play with an arch bridge. I think the tension is grows more and more possible when the degree of the arc or arch grows. Okay. so that could come into play it can. But for the most part, when you're building and arts, you have to worry about compression more than tension, gotcha,
so there's stylistic early and artistically design wise. There are all kinds of arches baroque, arches renaissance arches, a roman arches, they were the Romans built. You know, arch bridges that are still standing today. Have you been rum yeah man is too slow. you're walking along and over simulator Latin there's, like a two thousand. You're old aqueduct here in fifteen hundred year old arch to sit in their yeah. I remember the first time on Wednesday Europe coming back and be sort of like bombed out. You know as we walk along in is burger. King in this house is two hundred years old. She gonna Rome. I know my houses like eighty years old and it seemed super old
nothing. I roman standards now, but you know little drafty in those thousand Euro apartments yet, but it's so, neither because I mean like there's so much old, surviving stuff here that not all of its even meant to be preserved, some of its just like just there. It's not like a part of a Parker and historic exhibit. It's just part of the city yeah yeah. I have heard the other tourist complaining about how dirty Romas and Moses I come on. It's it's an honor on part, it's been around for a long time. He had a two year and also don't be stupid, and this look around you like their complaining in front of a two thousand years, fountain idle notice. That was particularly dirty. I mean it wasn't any more dirty than like New York or in any other big city hiring, but the
the thing with the arch, though very stable, once you get it built, but the building process area is tricky because until you connect those two ends. That's what gives it its strength. So until that happens, dicey area some scaffolding, yet in they used to build woods, Gulf scaffolds and supports to hold the thing in the wood building. and now they used suspension cables like I think the biggest arch bridge on the planet is West Virginia New River Gorge Bridge, and that thing is unbelievable, it really is in what's cause when you look at it it just. It uses the cliff calls on the walls of the gorge as the abutments beautiful stuff super strong, and that's where I worked with. We gonna talk about energy base. Jumping, I know that's the fact that ties these two punk area where they have Bridge day talk about elegantly.
Simple so suspension bridges for my money are: where tat I think they deserve their own episode. Pre, I'm pretty much there that complex like this is just the briefest overview of bridges in general, but especially with suspension bridge. Is it feels like there so much going on with those things I agree, I mean Kingbirds did like an eight hour long documentary on the Brooklyn Bridge alone. The industry is a deep diver, really is their overview, guys with a giant helmet, take overs giant Erika it s a pretty big aired. Our aid suspension bridge is we mention, of course, Golden Gate Bridge and the Brooklyn bridge. This is when you have your DEC, your roadway suspended by cables between can be. a number of them, but to at least two tall towers,
there- are supporting all this weight and compression is pushing down trailing up to those cables and transferring all that compression threw off those lovely cables right, so I mean another way to look at. It is exactly what it sounds like it's. The bridge is suspended from cables right, If you really start looking into what it's doing, it's not just holding these things up, what's what's going, is there is a transfer of that natural compression of the deck up through the lines up through the cables uptown up to the tower which, like you said, send him down to the earth right, so the the towers that hold the bridge up are, at the same time distributing or dissipating the forces of
Russian that are trying to pull the bridge down into the water below it. Yes, in the attention you also have to deal with as well, and apparently you deal with that using another part of the structure of suspension, bridges, which are called anchorages yeah. Now, that's just what the towers connected to the base right now, no harm. So it's like gum anchorages is like the abutments. Essentially, yes, a thoroughly left and right there, like a suspension bridge is abutments where that, as you get closer to the middle of the bridges that, where the towers Aria, but on the very end like say where the roadway hits the bridge, you can have a massive piece of work. Fucker massive piece of concrete and those are the anchorages and you have horizontal cables. They distribute the compression from the bottom of the bridge to the anchorages in those days
as for those into the earth yeah- and you might also, depending on the size of your suspension bridge, have to have that below deck trust as well to help stiffen the deck. And you know if you have it. Four thousand foot bridge you're gonna have all kinds of trusses in decks. cables, and I think it finally figured out what it is about bridges that I love is that the the market The structural design that it needs to be strong, also happens to be beautiful. You know what I mean, like the way the cables are arranged. It's not like there like this looks great like well. It has to be like this right, but it also happens to be very striking a grace Jones. You know me yeah, that's absolutely so so suspension bridge is your favorite. Her,
I like him, a good have so much going on yeah like trusses, because they're so elegantly, simple and they're, just tough as nails, there's a bridge for everyone. I think there really is the cable stayed bridge and we should say that suspension bridges when you think of a suspension bridge, probably probably think of the Golden Gate Bridge or something like that right classic suspension bridge to towers, to anchorages, less suspension, cables to suspension bridge anything. Well them they're, probably pretty new wrong suspension. Judges have been found in various forms for hundreds of years, at least, and apparently the were masters at building rope, suspension bridge is out of woven grass, crazy man, yeah fifteen hundreds. They discovered the Spanish Conquistadores
stumbled upon these were like what in the world is going on here right, because the smart Europeans then figure this out for another like few hundred years after that, that's right, the the Inca still have one of these bridges intact Spain's ninety feet and they re make it every year as part of a three day. Festival. Really nice, which is why it still test case Ass woven grass drawbridge didn't last all that long Missis. Early, even though why, when its fresh new strong near as an expiration date right using but apparently is will learn all bridges, Heaven expiration date through our. I we'll take a break then, with that tease and talk about the cable stay bridge and then might die on a bridge Wendy support for
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like you from the unexpected right. So we're onto your favorite, my friend, the super sleek modern, looking cable stayed bridge which is actually actually chile has been around since world war to a beer, but the idea, which is a modern. The idea came from a dude named fast, ran chick gammon and he was a kid.
very of Kepler Ambrosch. He and he basically came up with the first designed for a cable, stayed bridge back in the sixteenth century. So what was the nuts and bolts of this thing? So? Basically, it is a rather than to towers, like a suspension bridge uses a cable stay, produces one tower well my eyes on him more than one but ok, but for a particular span of bridge here, there's one tower towers that one's span Riah. So it's basically, you can't use it for his long of a spanish suspension bridge right. But if you have a slightly shorter span and you dont one spend quite ass, much money and you dont want as many wires up there in everything you can go as the cable stay bridge You have one usually tower holding up all the cable in the cables can either all connect to one point which is called
a radio pattern, yeah right. So it's like all these different cables are connecting on the bridge deck at different points yeah, but they're all connecting at about a single point on the tower again architecturally lovely, very neat, look and yes and then another way that you can do. It is an appeal, well pattern, so their connected at different points on the deck and connected different points on the tower, and that's the case with the Erasmus bridge, which I think is the most beautiful bridge in the world's in HOLLAND. Our welded in surprise, me. I mean look at that thing like that pal area. Something else fear I wish you guys could see. This Are they can look it up? It doesn't look like very dutch, though no. It looks very much like the New HOLLAND. I guess you're New Amsterdam, I'm just picturing like HOLLAND, I think of you know wooden windmills. How am I to loosen stuff
sure yeah. This is modern Hollingford. It looks like some. Nobody, unlike Sidney will they have great bridge to they do maybe that's what I'm thinking living Brit. All you ve done what those was asking to say. Another design for cable stay bridge looks a lot like a sailboat yeah with them the the tower staining straight up and on each side, cables going down at a diagonal from it to make it look like a sailboat, sale, right and mast and again for structural integrity, more than anything right living bridges. Sure why? Yes, we should say cable stayed bridges. Are they can't be as long as suspension bridges, but they can be pretty long like up too close to three thousand feet but, as I say and like, if you ever a shorter span, an you dont want to use
many materials and hence you spend as much money. Cable, stay bridges, great alternate, yeah. I wonder when cities, I wonder what the considerations are like money. What you are Guess money first inform money. What you'd probably is best for the the land, but also bet that architecture comes into play like how it looks in the city scape. Don't you think yeah, like give usually see you have some sort of will accept several designs. competing designs and then probably like in Atlanta case, with the Seventeenth Street Bridge Gaza, the cheapest one, as it falls down under traffic later, like a couple years later, did happen, yeah win like tooth two years ago, really yeah man, it was a big deal. Luckily it happen it like foreign them wearing a five in the morning, but like when you walking on the bridge. You know the side stuff here, one whole sigh
fell over on the suddenly, I find it under the connect irregular yeah. I can remember that yeah, but it's an ugly bridge to begin with three million dude. If you're listening the guy who design it. I'm sorry, I don't mean to insult your work, but I do but do better aid. That is, the city could have done better. I think yeah, but again I think when it came down to you, I'm sure was all of these are beautiful, but we're just gonna spend the money on this one right or whoever get the biggest kickback. However, that came from land to be cynical. Living bridges out. If you get a northern India to thee here we go the MEG Eliah region? I think those get close enough. They have something pretty remarkable and they are called living bridges
and what they did was it so rainy there that all of their natural bridges were having a hard time staying intact because of all the moisture from monsoon season air- and that's in, I can't have a natural bridge with much water, so they said why don't we take these tree routes and grow them the ground and span a river over the course of a year. in years and years and then basically planet on the other side into the ground, and this is now a natural tree route bridge guys, like giant living bonds. I figured they retraining react ago, a certain way in that they would take a tree felled tree and split in half an hour.
That is the guide right. It's like the structure so that they were building in arch, but they were making an arch like sort of a temporary bridge exactly and they let the roots grow along that and like they would plan these things. I really do plan these things out over the course of like a decade yeah and I get the impression it's the whole town's responsibilities. At least some people in towns responsibility to make sure that You see a route stern and go down in the wrong place. You pick it up and put it back on that fell log. That's guiding it across the the way yeah it's pretty much like it requires patience. Obviously, but it also. I imagined it Today, someone wants downlands like looking good, yes and then just walked away again pets. The bridge says: keep growing or walk across in ten years. Buddy and apparently things can last up to fifty years are the largest one that they have up to a hundred feet
Which is thirty metres for our friends in India. Crazy Anna can bear the weight of fifty people unless up to five hundred years, not fifty the citizen with ice at fifty as fifty people. Well, it's crazy. Like a you, gotta, Google. These things the very pretty very pretty it looks very dark crystal e out, yet only I mean, but they're not unsettling at all, like the dark crystal which, by the way, if you ever in Atlanta, sometimes people say I am counting Lana dear. What should I do go to the centre for puppetry arts agreed and just look at their free exhibit, which includes a full size? Skaggsy, it's terrifying, yeah they have out. We ve talked about this before they have em an otter, What is more, I hear me that was pretty pretty magnets Manila. for I M in order to meet you to their due and actually ass. I was just
museum of the moving image in Queens AOI. I saw you post something about that. They have a madman exhibit right now, it's pretty neat bow was pretty cool they. I was not there in time for the gym Hansen, when they're they're putting that in place, I think for Linux coming scamming, let's get to him well. They're ups go back and we went to the yoke of honor exhibit at Mama arson. She something else, did she's got a pretty cool mind yeah. She had she had this wine display and it was titled three spoons and it was just for spoons in a row. It was had three love that stuff here:
so I recommend. That is why I am not a fan of her music that I actually got turn under music in the listening room, they're gonna band, it's crazy! It is weird stuff I kind of like it. I mean she's. Definitely one of the most like original thinkers out there and she'd been at it for awhile, and a lot of stuff went back to the sixties like the early sixties here and talk about weathering criticism and still to speak, like screw, you near yoga ANA care. What you say well, she was exam. aid to recently murmured Palmer, current came I yes, I like it was not yoga honour that broke up the Beatles. Our saying that took em like fifty years to come out and say it yeah she's like what it kill you you ve told me privately many times, but will press release to you are so we talked about compression and tension being the two main forces. There are quite a few other forces, dozens even
and act on a bridge in a negative way in the scariest one. For my money is torsion, If you ve ever seen the video very famous video of the bridge and what is it the Tacoma thick to come a narrow spread, the common areas bridge when it looks like a wet noodle twisting in the wind air was nineteen forty, its nuts. They have like footage of this whole thing. Just undergone this destruction that kept this going on and on- and I am finally the bridges comes down here. The craziest part is when you're watching at you just think our man look at that thing. It's nuts and thank others, no one on it, You see, I can t working on it and a car Yan guy ran. There is a door there's one car in there and there is a dog trapped in the car and then some guy ran and got the doll I waded. Yes, pretty great hero stuff. Sure then later on, I don't have it the same guy in another guy you're, just to completely new guys, they're, just walking along it. This is after a horse.
Has fallen into the river. He added the section there walking on still swaying were there the only way from them, but a brave step back from the bridge man. So that's torsion at work. Yeah, that's a big problem. The designers is spent in bridges face because you have a deck, that's being old from its being held aloft by cables right, it's not like fixed to anything below it. Necessarily yeah? I mean that being suspended so just like on like a rope bridge or something like that. It's ways very easily right yet towers or strong. But it's not. You know directly connected to those towers right. So if you have a swaying bridge in between them right it and the thing is swaying back and forth, but if
One side starts to sway over the other side and all of a sudden, you haven't opposing circular force and that's torsion and that can basically rip the bridge in into which is sheer yeah. Well, that's the other awful thing that can happen. It consumes snap. Well, not snap, a guess, but breaking the two parts yeah. Well I mean snapping is the result of compression. Yes, shearing would be what it's called technically exact words to the the same span of bridge has the two opposing forces acting on it at once in opposite directions, and it goes. It may set terrible sound if you want to combat torsion many ways to do this year. You're probably gonna have a debt truss goin on to help out saves the day. Tat trust save the day. You're gonna have you gonna. Do wind tunnel tests if it's a modern bridge beforehand,
Well, you're gonna make a model and do tests and see like out his wind effect this bridge, and what do we need to do? But the thing is with the with the two common arrows bridge in particular, they did tests. They had that thing rated at withstanding Windsor, two hundred and twenty miles an hour, but the winds that day that brought it down we're only forty miles an hour and firm on time, they're like what happened and somebody did you notice was. It was mechanical residence. It was yet did the deck. Truss was not sufficient for this. And that was part of it in the way that the wind hid it right, an angle caused the final thing, Wiki dimension residents, which is a sort of its vibration. Basically, the gets out a hand, so residence to me, I think, deserves its own podcast too near awesome.
thing every especially anything that we build from an airplane to a bridge to watch her it. It has a certain frequency where it will really pick up force really absorb force in I'll run through right. So let's say that your brain has a residence. That's all I get a frequency of ten, that's probably totally ridiculous number that I just say bullets say it's a tent right and I must say that, Incomes added at forty miles an hour at just the right angle, and it makes its way at a frequency of nine will that bridges gonna beat it's gonna sit there and sway, not a big problem If that win hits it at just the right angle at just the right speed is in it, swaying at eleven, it still not quite a problem, but if it gets it just right and it started swaying it too
all of a sudden those ways are going to become more and more pronounced because all that energy is flowing through at its maximum potential that edits freest flow, because it's hitting the bridge at its natural resonance right, yeah, that's what caused the Tacoma narrows Bridge take to come down because once said things starts going, there's no coming back from it. We could see it happening, it's gets worse and were exactly in that's that's because it hinted at just the right frequency here. They like in it in the article which I think is pretty down to earth of a snowball rowing downhill exactly does keeps getting worse and worse and the you can't stop it's a, but isn't that bizarre You a bridge has a natural residents, unnatural frequency, exert a link. I would assume that would vibrate
It did not occur to me at all, and I was talking to Adam about this too, and I was like so I saw they building Seiners bridge designers. They will fine tune structure so that it resonates at a frequency that it's probably never going to encounter from an earthquake or from wins or whatever yeah. I'm like. How do you do that? And apparently it comes down to the bill. Materials you use these Epps. You used the structure, The way you join those shapes together, and you can basically say I'm giving this building a frequency of one five right, whereas I know all of the wind in the area ground movement from an earthquake is gonna, make it vibrated a frequency of seven, so it'll be fine. Yeah, one way like you said they can do. That is by not having like one way short the sections right of the deck. Let's say
In that way, the vibration, when you have these overlapping plates and smaller sections, it's gonna, create and friction to disrupt their frequency right. It old change, the frequency that the brass moving it, but I mean not just bridges to you- have to take this in taken due account like airplanes right sure you, you can't use engines on aeroplanes that create vibrations, IDA frequency, that's at the NASH, natural residents of the airplane body. Yes, airplane bodies, gonna come apart just from turning the engines on your kitchen Hutchinson, the airplane wing, starting the flap harder and harder right by apparently the the more common thing. When you have a disaster, a catastrophe from a residence, a mechanical residents problem. It's like one boy. Does I can't take it anymore and stops, and then that leads to a cascade of failures. They ultimately has the bridge coming down interest. I think that's fastening! I had no idea that you have to worry about frequencies in vibration
the main idea, ITALY, while the bridges you ve built of collapse, they collapse pretty well. If you there, heard. The old figure down like a french boxer mean sounding But I was a glass Joe reference member him from my Thyssen's punch up no word of honor. He says he was french glass Joe. I gotcha glass jar and he went down Dislike Sagoth Taylor so easy well, which was it a second potatoes reference by? He was both you and delicate sack of french potatoes. Yes, french fries right. My bridges go down like a french boxer, but Class Joe, the french boxer went down like a sack of potatoes, gotcha air go. My bridge is go down like a sack of data. If you ve ever heard, the old wives tale that, like an army marching across a bridge in step, can cause enough vibration to take down that bridge. It's true that could have
yet. So in any event, I am at the right frequency right yet more time. That's they will break step. In other words, there rhythm is, and all the same, to avoid that scenario, and there was a bridge disaster. I saw that Time Magazine slide, show where that is, and there were there, a pair of sky, walk bridges inside the higher Regency Kansas City, hotel, in the lobby they're just like raised bridges, church going through the lobby and they collapsed in nineteen eighty one and killed like a bunch of people, because thirty something people, people marching dancing their dancing on the on the sky, walk and you think up to today or yesterday when I started researching this right, like I just thought: that's weight or pressure, something like verbose dancing it didn't. It never occurred to me that the river had something that really add always heard that Europe far more,
France and I am naturally fuel engineering. My for another is just always heard that, like you know, even a bunch of kittens walking across could cause that in that the reason they said kittens of courses, so it has nothing to do with wait right, cause kittens knowing nothing and consequently, I think liner, Richie to change the name that song caused the accident. I think you're. Really it was a low, oh, what a feelin when you're dancing on the sky walk and he had to change it the ceiling at almost like that's weird, it's gonna ceiling, but it rhymes there's like here, but nobody ever died from dancing on the ceiling I guess the final thing we should mention is that whether obviously will play a big impact where they talked about wind, but
the years that the materials they use in the design is gone and to take account things like wind and what some damage? No, I think the freeze thought cycles huge, yeah, alt, sure, salt exposure, if it's gone over like salty body of water near makes sense. There's a lot of things that are trying to bring a bridge down. Nature abhors a bridge basically as much as a vacuum, a gown which got there's probably around six hundred and thirty thousand bridges in the. U s alone, because there are six hundred and seventeen thousand nine hundred and thirty five in two thousand to say this and they Adam they were adding a man about a thousand a year may be nine hundred a year, assist the? U S, the world's longest bridge complete, in two thousand ten, the DEN Yang Coon Sean Bridge. I think I've seen pictures of that. It serves as a railway bridge.
for the Beijing in Shanghai Railway. It's a hundred and two mile long bridge, that's nutty over water, I'm a big fan of its of cities with that multiple water bridges. While the Twilight Pittsburgh Pittsburgh Portland, Budapest, yeah big fan Atlantic does we produce, but it's not like. I used to go to them. The chatter who'd you river legs, Nobody goes into Chattahoochee INA. What sure I got. One more thing I want to shout to PBS is build it big website near which is like beyond Ninetys as far as websites go, but it was exe. worryingly helpful and understanding the forces that organ bridges, different types of bridges, different, specific bridges, great website and thanks to Adam, I guess you get some information from them. Examined. Was he ended? Talking you about her? Was he had on the? and go on. My car just shut up and watch intimidation,
he was. He was then to talking about it efficacity with ear, and I actually have to shout out to you may take. As I told you, we are building bridges. They were talking about bridges. She sent me a bunch of stuff on popsicle bridges. Apparently there's a a indigo go for the world's strongest or Canada is strongest popsicle, bridge they're, trying to build that means for, and they have like, starts six Green already for our popsicle sticks for them, since everybody gets shouted out to all over the place in this one higher. That's nice stuff ban. If you want to know more about bridges, you can type that word into. The search bar has to work stack and since I said, search bar it's time for listener, mail I'm gonna call this a couple of street gang responses read over the next couple of years.
here is one I had to write in about your street gangs. Upso does it was interesting pertains to my job. Short version is that I worked for hospital base programme. We see every gunshot wound victim in stab established victim becomes threw out about forty five hundred a year in about two None of those our gang involved are you guys mention how you found the number of gangs to be hard to believe, but I think you may be thinking with street gangs as one entity that has strict borders and lots of people My experience, larger gangs will sometimes incorporate smaller gangs. Sometimes larger gangs will split often many many smaller groups people go in and out of gangs and are sometimes affiliated with more than one. Currently we have about Seventy in our city alone, a substantial amount of those have less than twenty members, like many gangs super gang such projects. According to this paper on street gangs in Boston, eighteen percent of the gangs in the city have less than ten members.
Thirty. Four percent have tend to nineteen members, so I, while the numbers you gave seem shockingly high, they also seem to be in step with the current climate that is from area in what city did she say? You know, I don't see that dumping. She said those Boston or she does reference Boston or Thanks Le Marianna. We appreciate their email and you keep on coming one. In a more about gangs, I had the impression the whole time that, like one way or another. We were officially your unofficially misinformed, maybe and also let us know, who's the coolest famous person you ve ever met. You can tweet to us. It s fire escape. I guess you can join us on Facebook that council established you can put it in an email to stuff. Podcast has the force tat come and as always, Ernest that are home on the web stuff. You should know step. You should know
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Transcript generated on 2021-03-07.