Well There‘s Your Problem - Episode 71: Florida International University Pedestrian Bridge Collapse

Episode Date: June 9, 2021

bridge fall down go boom Slides: https://youtu.be/W8-ImMaRVNM Our Patreon: https://www.patreon.com/wtyppod​ Our Merch: https://www.solidaritysuperstore.com/wtypp we are working on international shipping Send us stuff! our address: Well There's Your Podcasting Company PO Box 40178 Philadelphia, PA 19106 YOU ALREADY SENT US ANTHRAX so please don't bother in the future thanks

Oh, crap. I duplicated it. That's the opposite of what I want to do. Oh boy. That's great. Meanwhile, I noticed that my GoPanther's fun screen name has been shortened to simply GoPant. GoPant? GoPant? Like a dog. Yeah. Like me right now, I'm so fucking sweaty.

Have you tried like getting really loud air conditioning and like moving it directly adjacent to the microphone? Shut up. I have central air now. Very nice. Congratulations. The podcast gets slightly successful and you manage to get like central air. I also have central air at the moment on account of I only have one air conditioner in a house running and it's big enough that it, you know, cools the whole place.

You're welcome. Thank you, Liam. Okay. What are we here for? What are we here for? We're here to do a podcast. So let's do that. Okay. Fine. I see here some interesting lime green fire trucks. Oh yes. We have to do the introductions though.

Hello and welcome to Well There's Your Problem, a podcast about engineering disasters with slides. I'm Justin Rosniak and I am a person who is talking right now. My pronouns are he and him. Okay. I am Alice Caldwell Kelly. I am the person who is speaking now and my pronouns are she and her. God damn right. I took a bite.

I know. Hold on. I'll do bits to like cover for you. Not good. Not good. I'm Liam Anderson. My pronouns are he and him. Now back to mute for five minutes so I can finish my dinner.

Okay. What are you eating, Liam? Nachos. Nice. Delicious. They're delicious. Thanks, Corinne. It's like not really a podcast friendly food though.

No. No, it isn't. It's probably pretty friendly for listening to podcasts. Yeah. If you listener at home have some nachos, go ahead and eat some nachos. But don't record your own podcast while trying to eat nachos. Otherwise, you'll have to like do the mute button dance that Liam is currently managing. Yes.

So what do you see on the screen in front of you? It's a bridge, but most of it is on the ground. Hmm. Doesn't seem very useful. It's not supposed to be like that. Wow. Today, we're going to talk about the Florida International University pedestrian bridge collapse from back in 2018.

We're getting more current with these. Yes. Well, the NTSB released the report, which I then skimmed over. So you could do the episode. It's the things like 120 pages and I only had like today to work on this. But before we do that, we have to do the goddamn news. News. Okay.

A boy is yeething himself. I was about to say Jeff Bezos is about to go into outer space because he wants to get as far away from Earth as possible when he's not CEO of Amazon, which I guess is he's about to become not CEO of Amazon. He's going to like skim the edge of space. Also, he's taking his brother up there, which is okay. And they're going to like do a flight to the edge of space and then come back down again. I mean, I it just always seemed to me like like it's surprising.

We have the world's richest man. World's consistently richest man. As opposed to Elon Musk, who is occasionally the world's richest man. And yet the Blue Origin spacecraft is so much crappier than what Elon Musk does. It's weird. I don't know. It's like it looks very like low rent. Like I'm going to use a in fact, I think it's the same font as we use for the goddamn news

on my space capsule. You can tell by the leg of the are it's different. Yeah, I didn't know maybe maybe because I know nothing about this. Maybe this is like some incredibly expensive font that like you pay thousands and thousands to use and like gets lots of design awards and looks almost identical to the font that we use for the goddamn news. I do like it is midlife crisis as opposed to a normal thing like buying a Corvette or a 9-11 is to go to space.

He said that the space was like the only thing he could think to spend his money on, which is fucking great. Just cool guy stuff. Dude, just like that's the thing is like when Bill Gates is like, well, when you talk about raising the tax rate to, you know, whatever 50 percent, I get kind of nervous. Like, what are you? What are you possibly spending the money on? You're spending it on fucking farmland.

Like, no, it's ours now, Bill. Well, he's also spending it on space, just horizontal space. And no, I guess we can't say about his associations with Appstein. Yeah, he's spending it on divorce lawyers from the land. He's getting divorced because he hung out with Jeffrey Appstein too much. Yeah. Which as far as reasons to be getting divorced go. That's a good one.

Yeah, I'd probably divorce someone who hung out with Jeffrey Appstein. I would take, you know, half of their billions and billions of dollars of wealth. Yeah, she's not getting shit. Well, they didn't have a prenup, which is going to be going to be. Yeah, she's going to get a lot of money. Yeah. Also, Melinda Gates, if if you're listening to this DM me. Yeah, I have a lot of watches I want to buy.

Also, I guess DM me. Yeah. I'm not selfish. We could have like a polycule thing going on. Nevermind. Nevermind. That's too many things to balance. No, we got to keep this podcast a professional relationship.

I mean, come on. I don't want to wind up in a Cincinnati DSA situation. Yeah, but you used to live together like professionally. Right. It was like a Bert and Ernie situation, you know? Yes. Yes. Yes.

But we always kept it professional, especially at 3 a.m. Just flinging beer cans off the back deck. Yes. I hope he crashes. I hope he crashes too. It'd be pretty funny. Oh, so we could. Oh, so we could say I hope he crashes.

But when I do not threatening him, I'm not going to do anything to ensure that outcome. We're hoping for force majeure here. We're hoping an active God. A studious acts of God's love, if you will. Yes. Fucks up this this incredibly bold, incredibly divorced man with too much money and his and his spacecraft for dipshits. If this guy doesn't crash and the flat earth steam rocket guy does,

you know, there's no justice in this world. I like that you're still, feels like you're still holding out hope that there might be justice in this world. Yeah, we haven't crushed that one out of Justin. Yeah, we got to we got to make moves on that. Put your citizens is a mom hat. Put your citizens is a mom hat. Citizens have put your citizens is mom hat.

Well, it's no good, Liam. I don't want to sell a hat now. It's like put your cynicism on hat. It's better than the discourse had. We don't talk about the discourse hat. I don't want to get cancelled again. Um, anyway, so I only put one news in because I thought we should just start recording. Yeah, we were an hour behind.

Yes. So all right. All right. So I thought a good place to start this podcast would be to ask what is a cable stayed bridge? It's a bridge deck held up like quote cable stays anchored into towers. Yeah, it's different from a suspension bridge. Cable stays require less anchorage, but a stiffer deck. Not deck to resist compressive load.

I two require a stupid deck to regroup. Cable stayed bridges look more futuristic and aesthetic that's suspension bridges. And yeah, way to go bras. And as such, they are in demand from clients who want that sort of aesthetic, i.e. morons. Yes. So Liam just read all the notes. Yeah. Okay, I had a podcast. Thanks, everybody. Hopefully we'll see you next one in the common areas episode. Cable stayed bridges are sort of like the modern aesthetic thing,

even though they've been around since like the 19th, the 18th. Yeah. We talked about it on the kind of travel episode, right? Like that's half the shit he makes is like a funky asymmetrical cable stayed bridge. Yes. So like they're very much in demand by certain people who want sort of a modern, like aesthetic to whatever piece of infrastructure they're building. So like here's a here's a local one. This is the Christian to Crescent segment of the Skookle River Trail, which is currently out for bid.

I don't like it sort of looks tragic. It looks like I know it's supposed to look like it looks fucked up on purpose. This only exists because the local gas company wants to maintain access to a dock that they never use. But they could use it. Yeah. And this is the future holds. This is one of those situations where you wonder, okay, is this span really being spanned most efficiently with this cable stay structure as opposed to, I don't know, have a deeper concrete girder, you know, it's, you know, a one old guy with a ferry and then be cool.

You just like ring him and he like sails across. Oh, that'd be pretty fun. Well, it's not even a cross. It's just downriver. This is right next to the shore. What the fuck do you need a bridge to maintain access to the dock for the gas company? Okay, fine. But so you but you need this like grotesquely overdone bridge to do that.

Yes. Okay. I mean, fuck it. If you're just going to do like infrastructure stuff and spend a lot of money by going into the Z-axis, why not do a tunnel, just a bike tunnel? Oh, that'd be that would be complicated. But you know, what are the effects of this is, you know, there's a very long design phase for this bike trail.

And it's been out for it. It's been we've been waiting for this thing for about six years now. You know, and it's I don't know. It's costing like 50, 60 million dollars, something like that. Some crazy amount of money. And you know, I don't I don't know whether you need a sort of signature span like this when a deeper girder could have done just as well. But on the other hand, you want the aesthetic, aesthetic, aesthetic, aesthetic.

You can take this to its logical extreme. This is the Bolt Bridge in Melbourne, Australia. It has these two towers, right? But it's it's a simple cantilever span. The towers are just there for the aesthetic. Stupid aesthetic. I mean, that's like I want to build a couple of towers on this bridge. Yes.

Which at least you could. It's more honest. Yeah. And you could monetize it by making it an observation tower. I guess so, yeah. There's two blinking red lights on top. Maybe for $50 extra, you can turn the lights on and off. Maybe it's more like rude and morse code.

Stare into the light. I don't think the pilots would like that. Maybe they'll maybe make the light RGB. Gamer Bridge. I hate the Gamer Bridge so fucking much. Never make a Gamer Bridge. Make a Gamer Bridge. No, if you're not pluses, you'll make a Gamer Bridge.

Oh, it's like hooked into a fucking Alienware case at one end. There's just a guy playing fucking PUBG and it's pulsing. I can see it in my mind's eye and I hate it. You should see what my computer looks like when it's operating. But it's not because my 30, 70 is out for RMA. There's RGB on my soundboard that I use to do the drops. And I hate it so much. I want some nice.

I want like, can we bring wood grain back? Can we bring like wood grain and analog switches and stuff back? My buddy has a PC case made out of wood. All right. And maybe some brushed aluminum. So it's really nice. It's made out of wood by a company in the UK. It's a mini ITX build.

If anybody wants to like re-case a GoXLR soundboard in wood grain, get at me because I would like maybe have some like reel to reels going on it. Speaking of tacky RGB, we have to talk about Miami. Oh God. The Godfather of it. Yes. So Miami is located at the mouth of the Miami River at Biscayne Bay.

It was named for the Miami tribe whose, or Miami right, whose territory is surrounded Lake Okeechobee from where the Miami River flows. This woman named Julia Tuttle from Cleveland, Ohio, owned 640 acres in South Florida next to the river and persuaded with the aid of a failed orange crop in North Florida, she persuaded a certified crazy guy named Henry Flagler to run the Florida East Coast Railroad down there in 1895. This is the only time a land purchase in Florida has ever gone right.

Yes. Oh yeah. This is not a Lee High Acres situation. I should also say, depending on how long this podcast lasts and how climate change goes, at time of recording, Miami is a sissy in Southern Florida. They're going to figure something out. They're going to just wind up abandoning the first story of every building. So Miami has got some really good art deco architecture.

It's full of a bunch of Cuban refugees who moved in during that Cuban revolution. A lot of them are rich. Some of them are not. Not a lot in the way of manufacturing or heavy industry. They got a little bit, a little teeny tiny container port, but it's always been about tourism and the city sort of expanded into this infinite radial plane called the Everglades, right? So it's got lots of single family houses, lots of sprawl, lots of golf courses, lots of big roads.

Fun fact, despite its glamorous reputation, it has the fourth highest poverty rate of any American city. That's crazy how that works. Yes. Right after Detroit, Cleveland and Cincinnati. Oh, where are we? Good question. Oh, we're categorized as a major city and we're the poorest, right? I think, no, because if Miami is definitely a major city.

Yeah, I hadn't heard of it until today. Just like my what? The other fun thing about Miami is, of course, what I was alluding to just now, which is that it is built on extremely porous limestone in a swamp. It is at like zero feet above sea level. And even as we speak, they have to run giant pumps to try and keep the water out of people's basements.

Miami, we're not as bad as New Orleans yet. Yeah, yet. One fucking degree of arc to the right. And it would have been Miami instead of New Orleans. Well, I mean, the difference being that New Orleans seems to be able to handle flooding a little bit better. Well, that's because after the pumps, they put it in 2005. Because they have those fucking pumps.

That and also New Orleans isn't like it's an older city. It wasn't built as a monument to man's hubris. This is true. Have you been to Bourbon Street? I respectfully disagree with you. Hubris in regard to alcohol, maybe with regard to flooding, not so much. You all want a 42 ounce smoothie that contains nothing, but strawberry puree and ever clear.

That'll be four dollars. Yeah. You want one of those hand grenade things and throw up in an aggressive four to six hours? I did not throw up. Corinne threw up. But I didn't. We're all very proud of you. Yes.

Thank you. You should be. So one of the things in Miami, as it grew, was they needed a big university, which was the Florida International University. We should stop for a second here and talk about the University of Miami, which as far as I know, it is not public. And it's in Coral Gables. In case you're wondering, if you've heard of the University of Miami,

it's not public. I don't know. I think parts of it are in Miami, but I'm not totally certain. Not to be confused with Miami University, which is in Ohio. And so this is the public one. It's part of the state university system. Why is it Florida International University anyway? What's international about it?

It was formerly on Spanish territory. No, it's Florida Gulf Coast that had the Sweet 16 run back in 2015. I mean, everyone was charmed with this small school. Everyone was charmed by Earl Roberts. And then it turned out this weird Ein Rand worshiping ghoul was their chancellor. And they got all sorts of shady, shady funding for all sorts of shady places. As far as I know, if I use clean to fame is that they had, is it Lane Kiffin?

There may have been FAU, but you can't stop the Lane train, who's not the coach of Ole Miss. I know nothing about the school, really. Go Panthers. Oh, right. FAU is the owls. This is the thing. Water has too many schools.

Me and Liam, our only knowledge of colleges that we did not personally go to, sports. Yeah. Yes. As it should be. Oh, I was going to say, don't sound so sad about it, Ross. So Florida International University was founded in 1972 on the site of the former Ta Miami airport alongside the Ta Miami Trail. I don't know how to pronounce that correctly because I don't live in Miami.

They still have the like control tower from the airport. Yes. Which is cool. It's a little bit like their president was like, no, we're not demolishing this. We're going to keep this aircraft control tower in the middle of our campus. It had very rapid growth over the next couple of decades. When it opened, it had an enrollment of 5,667,

and today it has 58,000 students. Yeah, it's either the first or second largest university by enrollment, like on one specific campus. Oh, OK, because it's the fourth largest public university in the USA. Yeah, but I think Texas A&M has the most kids on one campus, but a lot of those include the whole system. And then like UCF is up there and FIU now. It has about a million colleges with a billion degrees, the endowment's $200 million.

And of course, they're still expanding and they decided one place they needed to expand was to build new student housing north of the Ta Miami Trail, right? Yeah, because we've got to suck money out of kids. I mean, that's like, we did a whole episode about this about colleges. That's good. Basically, they're sort of the real estate funds that incidentally give you a degree in dentistry or whatever. Yes.

So they need more real estate because that's what real estate speculators do. Yes. Look at this beautiful cityscape. I know, right? I love the urbanism of suburban Miami. I love, I love to like sprint across eight lanes of traffic at three in the morning. One, two, three, four, five, six, seven, eight, nine, nine lanes of traffic. Hope you're sober for this.

So that the Ta Miami Trail is what some people kind of awkwardly call a stroad, right? Not a street. It's not a road. It tries to do both. That's such a fucking Florida thing, a South Florida thing to be like, it's called like Orange Grove Trail and it's 57 lanes of traffic. Yes. Bumper to bumper.

Yep. But it's both an arterial highway and a local street trying to serve local traffic. And it does neither very well. And it also creates a very dangerous environment for drivers and pedestrians. It's very expensive to maintain and requires a lot of enforcement of traffic laws, right? We've talked about those four-way intersections that just kill people. Yes. Yeah.

There's a similar road that runs through St. Joe's campus in Philadelphia. And a girl was hit by a car doing something like 55 walking back from class and she was she was not killed, but it was not. No, it was not pretty. Certainly. Yeah. Where I went to school, Temple University, where I spent the majority of my school years, had streets running through it.

And people would gun it at like 35 through this college campus. These are one-way streets. We didn't have anything like the Champs-Elysees here. But I just, I can't imagine trying to go to class hungover at fucking like 7.30 AM and just getting the absolutely railed by a car doing 7 day. Hey, it'd be more like, just kill me. Just fucking do it. Just fucking send it, please.

Trying to get into like the exam. I don't want to be here. But really, you've got to think how bad do I want this communications degree? Yes. Right. So, you know, this this route has no public transportation to speak of. And this stretch has inconsistent sidewalks. Not ideal for any kind of pedestrian activity,

least of all perpetually drunk 19 year olds trying to get home, right? So. Well, if the students want to like exist in a city, why don't they pull up their bootstraps and learn to drive? Yeah, learn to drive drunk. Just drive drunk. Yeah, more drunk driving. Drunk driving will be safer than trying to cross this intersection on foot.

Honestly. So, Florida International University realized in order to put student housing north of Tom Miami Trail, they needed a pedestrian bridge, right? So, one of the things about pedestrian bridges over Becher roads is they are a last ditch effort to solve a problem and they don't really work that well, right? Tell me about it. Glasgow has a couple over the freeway that goes through the center of town, another of our great urban planning decisions.

So, if you want to get from where I live in the west end of Glasgow to the center of Glasgow, you have to walk across a kind of precarious looking like pedestrian overpass over, you know, four lanes of 70 mile an hour traffic, which fucking rocks. Oh, good. Well, thanks. I even hated Penn's Bridge. I was only over five lanes. Catch me walking directly in the middle of that bridge.

And once I'm out in the clear like span, I'm fucking, I'm running. I don't give a shit. Yeah. Yeah. I mean, I don't run, but yes. So, these bridges are inconvenient for pedestrians, right? They're very inconvenient for disabled people. If you're in a wheelchair or something like that,

you know, especially if designers are using convoluted ramps instead of elevators. So, it's kind of Trava again. Here's a nice, here's a nice example. This is in seven corners, which is a big stupid commercial area in Northern Virginia. Say I'm a wheelchair user. I'm trying to go this way and I want to cross the street to go this way and then continue up the road, right? Yeah.

You got to go up and down to perfect cigarettes and then across four lanes of traffic. Well, no, because there's stairs here, which is relatively convenient, but I'm in the wheelchair. So I have to go all the way down to the horizon, come all the way up the ramp, then go across the bridge, then go all the way down the other ramp out of frame, and then go up. And I probably added like a mile of wheelcharing to get over this bridge. No, thank you.

That's ridiculous. So, you know, a better solution is to have roads that are safe enough for people to walk across that you don't need these big structures. The other thing is if you're an able-bodied pedestrian, a lot of people try and ignore these things, just try and cross the road because it's much more convenient, right? They're usually not very well integrated into a pedestrian transportation system, like, you know, there's not like, it's usually an afterthought, right? Yeah.

Hey, it's still better than the pedestrian underpass, which is urbanist for you will be robbed here. I understand they somehow make that work in like Moscow. I know the Soviet Union was really big on those. Bear police. Bear police. Yeah. Oh, Lieutenant Stephen.

All cops are bastards, except for possibly Lieutenant Stephen. So, you know, unless you're doing like a full Likubizia style separation of pedestrian traffic and automobile traffic, you should not ever need these outside of some specialized applications, like, I don't know, hospitals or something like that, right? These pedestrian overpasses are bad. Just make the roads smaller and slower, you know. But FIU didn't have any influence over the construction of massive stupid roads next to its properties.

So pedestrian bridge it is, right? And they decided we're going to make it fancy. We're going to have a statement bridge, right? Red boy. This is this is another problem with the American University. Too much money. Yes. Not that you'd know for anything that like they spend money on students for, but like

for statement shit like this, like, we're going to get, you know, Calatrava to do the new medical school or whatever. Too much money. All right. So here's the design of the bridge. Now, Florida International University wanted this cool ass bridge to demonstrate their superiority in the field of structural engineering. Since, you know, they're a major research school.

They also wanted to do something called accelerated bridge construction, because I think the accelerated bridge construction Institute was on campus, right? Basically accelerated bridge construction is you prefab the bridge off site and you install it over a weekend or so to minimize disruption to traffic, right? That's such a fucking clickbait ass means of architecture to be like it's so designed to get the kind of headlines is the same kind of headlines. It's like China built 50 hospitals in one day or whatever. Yeah.

And it's like, well, okay, cool. But what are you, what are you sacrificing in order to do that? And in this case, it's, I don't know, just a lot of stuff, it seems. Well, I would say that the accelerated bridge construction in and of itself, it was not the problem here, right? The bigger problem was the design of the whole thing and what they decided to do was in order to show they're a high tech modern university, we're going to build everyone's favorite kind of bridge, which is a fake cable stayed bridge.

Right? My favorite point is like fake cable stayed bridge. Yes. Rule 34, no. So all these, all these cable stays are fake. They're just steel pipes. Good. So it's like a truss bridge for the bunch of shit on top of it.

It's a truss bridge with shit on top of it. But the trusses are organized in such a way that they meet the cable stays. So you can see that the it's very inconsistent in the triangles. Well, that's annoying as hell. Yeah. So it's so that you could like have this like through line, which looks cool. Yes. And then there's only one line of truss here through the middle, but you could if you if

you're starting with it, like if it's a truss bridge with a bunch of ornamental shit on the top, why have you made the truss bad in order to conform with the ornament instead of making the truss properly and then making the ornament conform with the truss? What we've done is applied Victorian ideas about ornament to modern architecture. Oh, yeah, I'm sorry guys. I shouldn't have done that ornament. It's like it's like what they say function follows function follows form. Yes.

So, you know, so this is that there's a single truss down the middle. There's a walkway on the bottom. There's a roof on top. This whole thing acts as sort of an I beam, right? But the web is a truss and the floor and ceiling are the flanges of the beam. And another thing they decided was they were going to build it out of concrete for some reason. Looks cool. Couldn't get render right.

I guess so. Well, they had a special kind of concrete they used called self-cleaning concrete. So it's going to stay all like all gleaming and white. I guess you can't you can't use to like the other big thing for this which is like glass and steel because like it's too transparently dangerous to have drunk seniors on a bridge made entirely of glass in a city where when it rains it just fucking swamps everything. Everything's a swimming pool in Miami. Yeah.

We've just made a slip and slide for drunk college students. But also it's above like 10 lanes of traffic. Well, I would say you could quite easily build the truss out of steel, right? But they didn't do that. They decided instead to use something called post tension concrete, right? Oh boy. This this did not work. Well, Jesus.

Oh, we've accidentally made a goth slide. Goth concrete. Yes. All right. So self-cleaning, self-heating concrete. All right. So our basic idea. Okay.

So what's concrete, right? You have it's when you put some rocks and some sand in a thing and you mix it around and then you spread it. It's cement and other shit. Yes. Very good. I just forget what the other shit is. It's very, very, very bad intention.

Sand. You can mitigate this through reinforcement, which is adding steel bars to the concrete. And that's, you know, pretty involved to get in here right now. But another method to make it better in tension is either pre-stressing or post-tensioning, right? Hmm. So what we're saying here is that the concrete, you can put a lot of stuff on it. You can put a little weight on it and it's fine. But if you try and pull on it, it just pulls apart.

Yes. And that includes if you, let's say you have a some kind of vertical force on a concrete beam, you know, while the top is in compression, the bottom's in tension. So it breaks really easily, right? One way you mitigate this is you either pre-stress the concrete, which means, you know, you take a steel rod, you stretch it out, you cast the concrete around the stretched out steel rod, and then you'll let it go, right? And suddenly it's the concrete beams in compression, right?

Without you having to do anything else. So you can add load on top of it without it breaking, right? This is one option. The other option, which is more often used now as post-tensioning, right? So you cast the concrete with a hole in it, right? You run some threaded rods through the concrete, through the holes, right? And you put some big washers and nuts on the end and you tighten them up, right? And that compresses the beam, right?

Again, allowing you to add load on the top without worrying about it, you know, breaking, right? Just snapping in half. So you can use concrete more flexibly in an area where it used to be very difficult, you know, for stuff like, you know, long floor splans, big, long concrete beams, stuff like that, right? Because then it's like, what you've essentially made here is a truss of rebar with a concrete shroud around each piece of rebar, right?

Sort of? The, well, okay, so the way it's usually used is not the way it's used in the bridge we're about to look at, right? Because usually it's, you know, again, I got this, I fucked this slide up, you know, you're just trying to add compression to the beam in such a way that it can take extra tension. You're playing God with the forces. Okay, got it. But this is usually used for forces which are perpendicular to the direction of post-tensioning,

right? Which it means that for a truss, let's say, it's not ideal, right? Now, generally speaking, trusses, you know, they follow some set patterns with set angles. They made a wood or iron or steel, you know, at some point they were supplanted by simple girders once it was easier to roll big pieces of steel. They're never made of concrete, right? Because the forces are axial in the truss, right? They go along the length of the truss.

Now, we've all played those bridge construction games. Yes. Where you start out, at least if you're anything like me, you start out by going, okay, well, I know, I know how to make a bridge, you do a nice symmetrical truss. And then the little truck drives across the nice symmetrical truss, and then one piece is just like, whoop, don't like that, breaks, and the whole thing comes down, yeah. Well, that just means that your design has no redundancy. So, you know, one of the things is concrete, bad attention,

and every member in the truss is, you know, generally, rule of thumb is, you know, they're either an axial compression or axial tension. I mean, there's some more advanced analysis about shear forces, but those aren't the main forces, right? And concrete is bad attention, so you just shouldn't use it in the truss. Um, theoretically, one thing you could do is use a post tension concrete member in the truss, right? Which would mean that if I had a member that was in compression,

right, I would then add post tensioning to it, which was equal to the force, and then more, more than that as well in order to make that work, right? It just seems to me like a very stupid way to do it. Go Panthers. Which is why, to my knowledge, no one has ever built a concrete truss bridge until Florida International University tried to do it. So, no one has ever built a concrete truss bridge successfully? Yes.

And for a good reason, apparently. There are some truss bridges out there which have regular steel members encased in concrete, you know, for like, just for like weathering and that sort of thing, just protection. Oh yeah, but no one's done it. Or even just because you want to make it look like that. Like that seems like a responsible way of going like, right, I wouldn't do the whole thing out of concrete. If you can make it look like it's made out of concrete.

Yeah. Without, you know, which was like the whole, yeah. That seems to have been the emphasis for them to do it in concrete in the first place was we want it to look nice. Well, if you, if you want to do that, then just put some steel in there and then put concrete over it, right? Nobody will know. Yeah.

There's an FIU guy going, but I'll know. Yeah, but I'll know. So, all right, the design of this bridge, right? As we mentioned before, fake cable stay. It goes over. That's rough looking. Goes over the trail, goes over the canal, right? FIU bid this as a design build project, right?

So the same firm that designs the bridge builds the bridge, which is opposed to the more traditional design bid build, where one firm designs the bridge and another firm builds it, right? So they wound up with a consortium of FIG bridge engineers that's FIGG. They're at a Tallahassee and a construction management firm called Munilla. And then because this bridge was so new and unique, an additional engineering firm had to be retained for peer review of all the calculations to make sure.

Maybe you should have just encased it in concrete. To make sure it was all sane and sensible. This was a firm called Lewis Berger. I'll be right back. I have to use the bathroom. Okay. Yeah, I actually worked for Lewis Berger and I just told them at the time, make everything more rigid.

I'm really sorry, guys. I think I fucked up somewhere. I was about to say, well, concrete is pretty rigid. Yeah. I don't, I'm struggling to see how this could go wrong. Concrete trust, that'll be fine. Yeah. Yeah, concrete, concrete is strong, right?

Trust is a strong, concrete strong. Therefore, concrete trust is very strong. Very good. Very strong. Plus, plus it's got the ornaments on the top, the fake cable stays that'll give it moral reinforcement. This is true, yes. Whenever the trust is gonna fail, it can look up at the cable stays and think, oh, I've got this thing holding me up, even though it isn't really.

And it'll give it a psychosomatic effect. I heard that there was a justification for this cable stay structurally, which is that it would increase the resonant frequency of the structure, and therefore, it would be better able to resist vibrations from pedestrians. Always like a perennial problem with college students. They're always marching in step over bridges. You got to put up the signs telling them to break step. Otherwise, the FIUs like ROTC division is just going to collapse this by themselves.

I am back. What I miss. Well, the FIU marching step everywhere. Yes. The what? The university that we're talking about. The Florida Internet, the School of the Americas or whatever. So one of the things about construction is you actually have to build the thing, right?

And people get angry if you don't part. Yeah, people get angry. People sue you if you don't do that. The biggest part of construction is building the thing. As a result, it's a good idea to run calculations, build the finished structure and for various phases in the construction project. Now, this bridge was going to be built in several phases. First, they were going to cast the piers and the abutments at each end.

Then the long span of the bridge here was going to be fabricated off-site. Right. And they were going to place it in position using a pair of big, stupid, transporter doohickeys, right? Yeah, it's like the it's like a truck, but the bed lifts up. Yes. And then the smaller portion was going to be fabricated afterwards and then placed in a position in a similar fashion.

And, you know, this is all the minimized disruption to traffic on the trail, right? Of course. Of course. Yeah, I mean, obviously can't. Whatever. You live in Miami. Nothing is going to stop you from sitting in your car in like... Bumper to bumper traffic on the shots all day, right?

250,000 degree heat at the fucking center of Earth's yellow sun. With your like Starbucks sort of simply vaporizing around you. Yeah, because I think seven years is 7000 percent humidity. By the bright side, I'd love to vape my vanilla latte. I love to live in South Florida, wind down my window, blast the cloud of like super cool, vape frappuccino and killer horsefly with it. It's a terrible place. Florida was a mistake.

This is part of like a big American pathology about refusing to close any road for any reason ever. Oh, dude, I know. And then construction happens in these shitty irregular stages. And it's just like, I would much rather you just close the road down and inconvenience me for less time. Yes. Then this weird slow marching. You say that.

You say that. But then you'll get the British psychosis, which is you close roads when you need to. And, you know, you do research, you do repairs and stuff as you need to. But then everybody becomes absolutely psychotic at you, especially if they cannot see you working at that very moment. Hell has no fury like a British person driving past a work site where they can see no work happening. Yes, I've seen Top Gear.

No, they do that here, too, Alice. Clarkson always getting furious. Oh, protect the workers that aren't here. All right. Anyway. Anyway. Anyway. Anyway.

So. Wow, it just keeps getting idiot, sir. Yes. So here we go. We're looking at the bridge. Okay. So the idea here is member three, three, five. Um, seven and eight and 10 are designed to be permanently post-tensioned, right?

The other members are not except for, I got to switch colors now. Member two and member 11, which are temporarily post-tensioned while the bridge is being moved. Because it's being supported, I think, like here and here while it's being moved. So these would temporarily be in tension, even though they would normally be in compression, right? Yeah, I think there was some fuckery about exactly where they could place the bridge transporters.

So like they only had to close one lane of traffic. Just close the whole fucking road and do a good job as opposed to whatever the fuck this is. So of interest here is node 1112, which is over here, right? This is what we're going to talk most about. So this is, the nodes are the joints between the members at each node. There's something called a cold joint, right? And the cold joint is when you cast concrete onto concrete, which has previously been casted, right?

So here, here, here, here, here, here, so on and so forth, right? Ideally, what you do when you cast concrete onto previously casted concrete is you rough the area up in order to... You take it out in the alley. You take it out in the alley. You kick it, heart it's feelings a little bit. Yeah. That way, there's a better joint between the two concretes, right? This was somehow lost in translation during this particular bridge assembly.

Yeah, they took it out in the alley to rough it up and three guys like broke toes trying to kick this concrete. Yeah. Can you imagine that incident report? I tried to rough it up, but the bridge should hurt me and said my wife didn't love me anymore. That's why my kids don't talk to me. Boss, this bridge is tough. Yeah. You got Tony in the back crying like a little girl, boss. Now, so the full bridge would include more, more crap over here.

Another member that butts into node 1112, right? But this was going to come in later, right? And because of that, because you didn't have the forces from that other section of bridge, this bridge experienced different loading conditions, right? So, all right. The incident has sort of occurred in agonizing slow motion over several days. Oh, what a nice change of pace for us. Yes. So, on March 10th, 2018, the first section of the bridge was lifted into place, right?

Now, owing to the fact, again, the bridge transporter held the bridge from central points. The outer two members, 11 and two, were post-tensioned to a much higher force than they necessarily would have been otherwise, right? 280 kips and a kip is a thousand pounds force, right? So, 280,000 pounds force. Yeah. Me trying to squeeze into my like size 16 jeans. I feel you. I feel you. So, after the bridge was put in place, these two members were detensioned, right? And engineers immediately noticed a whole bunch of cracking started occur near node 1112.

Like basically instantaneously? Yeah. Cool. In addition to some cracking that had occurred earlier in February, while the thing was still being cast just on site. I like the ruler stuck in the crack for scale. Oh, holy shit. Yeah. That tells a story, doesn't it?

Yes. Well, I mean, some cracking is normal in concrete, right? And context clues can be used to determine whether it's of concern or not. But the cracking in node 11 slash 12 was the kind which was concerning. You know, it was about 45 times wider than a crack of no concern, according to the NTSB. I was going to say, a general rule of thumb seems to me to be that if you can stick a ruler into it, like a meter stick into it. And it goes down three inches. Yeah, that's kind of a problem.

Especially if the bridge is brand new. So there's a couple of issues with this node. Just design-wise, you might notice that there is a drainage pipe that goes right through it. So you have extra stress on the concrete right around that, right? Oh, good. Um, furthermore, I keep those clean lines. Yeah. God.

And then a lot of the rebar in here that was holding it in place to prevent shear forces was completely bypassed by a lot of the cracking. So that wasn't doing shit. Great. Great. What do you saw? Rebarant. Yeah.

So what you're seeing here is you have, it says here, interface shear cracking. This is because this member in the cold joint aren't meshing well together. It's not doing much because the cold joint wasn't roughened up. Another thing you're getting here is flexural cracking. This is from member 12 being pushed northwards, right? Because again, this member is not resisting shear at all. So this guy's getting pushed north. You have punching shear cracking, which is also from all this stuff moving north

at a very slow rate of speed, right? So, you know, the engineers at FIG realized this was a bad situation, but they also thought, well, we could probably fix this later, right? So we just need to get it in a sort of stable condition and then we can start to fix it, right? So their solution was, what if we bring the bridge back to the previous condition where it was fine, right? Oh, put the transporters underneath it.

No. No, I can't do that. That's a lane closure. Oh, my God. Instead, we're going to re-tension member 11, right? Uh-huh. Right. We're going to put an additional, since there's two tensioning rods,

an additional, I think, 520,000 pounds force on it. That'll probably do it, right? Uh-huh. Oh, God. And the engineers at FIG were not very concerned. There's some transcripts that were in the original report here. They were like, you know, so on. My many, we do not see this as a safety issue emails.

We're raising a lot of questions, which are answered by my many, we do not see this as a safety issue emails. Again, we have evaluated this further and confirmed that this is not a safety issue. You'll quit being cowards. Get on that bridge. FIG has further evaluated and confirmed that the cracks encountered on the diaphragm do not pose a safety issue and or concern. Okay.

Safety issue and or concern is a fucking great. That's a good lawyer speak. Yeah. There is no safety concern relative to the observed cracks in minor spalls. Uh-huh. Uh-huh. If I recall correctly, there was a meeting that was held where some inspectors and explained slowly and patiently to the engineer a record that,

yeah, these cracks look a lot worse in person, right? But I guess the engineer didn't want to drive all the way down from Tallahassee to look for himself. Okay. One of the things here is that retensioning this, the post tensioning to, you know, it's full, full strength was not something that was on the plans, not something anyone had done any calculations for. And as a result, what they were supposed to do was submit that for peer review, right?

Yeah. Or the other firm. Uh, and, but since the engineer record thought, well, this is just returning it to a previous condition, he didn't think he had to do that. So he didn't do that, right? Yeah. What do you want approval for hitting Control Z? There's no sanity check for a kind of bridge that had never been done before that was already

showing crack it. Cool. Yes. Great. Yeah. All right. So. That's terrific.

Let's, let's sort of look at our sanity check here. I think this is something which is relatively intuitive as to why this would make the problem worse and not better. So your problem is your node, right, is being driven by a force which is axial to the main concrete member, right? That force has two, two components, a horizontal and a vertical, right? And because this is at a very shallow angle, the horizontal dominates, right? So.

How erotic. Yes. And that's why we see a member 12 getting pushed outwards and sharing. Yes. So the idea is we return it to a previous condition by increasing the force on the post tensioning rods, right? Which results in more compression, which results in some more clamping force, which is good. And a lot more shear force.

I have restored this table to its previously unset condition by sweeping the table cloth out from underneath it. Yes. Yeah. So the, the post tensioning here is, is not, not, not helping you in any fashion. But again, big considered this to be no big deal, right? So they go ahead and do the post tensioning on the morning of March 15th, around nine o'clock in the morning.

And I believe during their last meeting about the cracks that day, it fell down. Oh, that's crazy. Oh, that works. Yes. So yeah, 147 p.m. The whole damn thing collapsed. Holy shit. Yeah. Whole thing went down.

It was all captured on video. It took about two seconds. One worker was killed, five workers were injured. They were all on the top of the bridge, I think, right, right in this box where they're blacked out. And then eight vehicles under the bridge were crushed. And that left two dead, or five dead, two seriously injured. Well, the good news is that a full, a collapsed bridge doesn't block any traffic lanes. Yeah, we've got, we've got a full route closure here.

Yeah, well, you know, you can't, you can't risk it. You know, some, some woman vaping a vanilla bean frappuccino out of her Range Rover might get upset. Also, the fact that all of the like structural members have big FIU raps on them. Yes. Yeah. That's, that's, that's awkward. That's pretty grim. So yeah, it's like being being crushed to death by a gigantic GoPanther sign.

But it's pretty awkward if you were an alumnus of the university. Yeah. You donated a bunch of money to them, like an idiot. Don't donate money to the universities. Never give, yeah, see the job the lady ran about giving your alma mater money. Yeah, donate money to us. Yes, subscribe to our Patreon. Yes.

Yeah, so the thing. We will also bug you, but not for like alumnus reunion, uh, letters. So some blew out at the node, right? And member 11 was suddenly budding into nothing. So you had a fracture up in node 1110 and the deck fractured at the next node, right? And then this whole section, which was otherwise structurally sound, suddenly rotated down into the road and yeah, fuck shit up. Not good.

So there was an investigation after this, which obviously just concluded. It revealed some interesting facts, like that the peer review firm was not qualified to peer review this kind of bridge. They just, they didn't know how to do it. I mean, no one knew how to do it. No one knew how to do it though, right? No one knew how to do it, but there were firms qualified to peer review a bridge that no one knew how to do.

And this was not one of them. I see. Okay. Understood. NTSB eventually concluded the main problem was underdesigned members, right? You know, you sort of basic back of the envelope calculations. Basic trust theory indicated that forces were much, much higher than what FIGG had calculated and designed for.

I think something like 46% higher at node 1112 and then 93% higher at 1011. The thing is, it's not like Florida International University had a school of architecture or an institute of bridge design that had a bunch of people who could do those calculations. So you had to outsource it to these guys FIGG. Yes, you just have to outsource everything constantly all the time. And you know, the problems were exacerbated by a number of other factors like the construction errors and the engineers did load combinations which were not appropriate. But had those been corrected, it still would have fallen down, right?

So yeah, it was a big, big stupid thing. And the FIGG engineering firm has disputed a lot of the report and have been trying to argue that if the cold joint were properly roughened up, none of this would have happened. I don't think so. I don't think so either. Yeah, I disagree. But I feel like the main problem here is that they just decided to build the stupidest bridge

possible for no reason. Right, just building boring stuff Jesus Christ. Just build boring, build boring, build boring. Building a boring company. Boring little things. No, no. But like this, like, we're obviously not against exciting architecture. We spent, like a whole thing talking about the Ruggerata Familia.

But the point is that when you're in stuff that's like meant to be utilitarian, whether that's like bridges or nuclear reactors or whatever, don't do it in such a way that the function follows the form, you know? My big argument is don't design cities in such a way that you need pedestrian bridges. Don't design anything, fucking. Yeah. Rising was a mistake. Right, it was a mistake.

It turned to a field. Yeah. You guys are plowing. This shit never happened when you were plowing. You got to go back to stuff that has one set of plans and takes 400 years to finish. Yes. Not even Anne Prim, but like Anne Goff. Yeah, I'm a medievalist, but a political medievalist.

For more, see our last episode on medieval warfare. That's right. Goff concrete, but like differently. Yes. Well, you didn't have concrete. The cracks, when you step on the cracks, they just play the cure for you. This concrete is cracked like my soul. If you had built this with flying buttresses, it would have been fine.

Well, that's the thing, right? If they had built the, even if they had built the towers first, right, that they were going to do last because they had the most time to do them, because they didn't have to close any roads to do it, that would have worked like a flying buttress, right? The tower? Yeah. No, it's just like a pipe.

Oh, no, it's just been a pipe. But it doesn't actually support anything. Okay. Can you cut this last bit out so I sound smart? No. So I think what we've learned from this is don't build a big, big bridge. No, don't build a big, big bridge. Don't build Miami.

Don't build a university. Ornament is, in fact, a crime. Yeah, yeah, that's right. Well, we've got- There's your problem. We have a segment on this podcast called Safety Third. This is already an encouraging image. This image has been pre-John Maddened for me.

Ah, okay. Hello, WTYP crew. Hello. I work at a municipal water utility and wanted to tell the tale of when my co-worker shook hands with danger a few months ago. This is going to be another Kronenberg body horror story. I don't think so.

Probably. Our utility uses water primarily from springs and deep wells, as well as filtering creek water when demand is higher during the summer. Thank you, suburban lawns. Abolished gulf. Yes, abolished lawns. We only operate 24 hours a day when we're running our filtration plant and use a call system the rest of the year

for emergencies that happen during the eight hours of night when nobody is working. The story begins when my co-worker was called out in the middle of the night to one of our deep wells. The chlorine detection system at the well had triggered an alarm after it had detected gas in the pump house. However, my co-worker didn't notice anything out of the ordinary

with the chlorine gas cylinders upon arriving, but did notice the well was pumping without any resulting water flow. So he shut off the well and waited for the chlorine alarm to clear so the problem could be fixed in the morning by people who weren't getting overtime, which we try to do when there isn't a pressing need for the water.

Waiting did not help to clear the detector, however, and after an hour and a half of waiting, my co-worker decided it was time for action. He had already inspected the separate room where the gas cylinders were, including using ammonia to check for any trace of chlorine around the cylinders in that separate room. Also during that time,

the sink in the room had been running with nothing more than the average amount of chlorine in the system. The next step taken was to slightly open the ball valve seen in the attached picture. Not sure which one that is. Not sure that matters. Yeah, and you can still see the aftermath months later. Not only did water come out of the pipe,

but so did a cloud of chlorine gas. The door is behind you from where the picture was taken while my co-worker was in between the pipe and the wall in the picture. Oh boy. Luckily, he started running quick enough that he managed to get out before he breathed in any of the gas, but that didn't stop some of it from rolling out of the building.

The next day was spent figuring out what the hell happened. I don't know. Like a chlorine alarm goes off. He doesn't even get it like a respirator or anything. Well, I would imagine a better option than getting a respirator would be to leave the building. No, that's true. Nature's respirator.

Nature's respirator. Just get away. Yeah, just get upwind. You can leave. I saw a thing of genuinely, it was national security stuff, how to best protect yourself in the event of a chemical weapons attack, like a terrorist one, a thing which has not happened outside of Japan, to my knowledge.

And it was literally, you just go outside and go upwind of it. Just leave. Yeah, I mean, it worked for some people in Bhopal. Yeah. Do you know where upwind of you is right now? You should find out. Stop the video, find out. After making sure everything was off and aired out,

the department took apart the operating control valve in the left of the picture. That's this guy. Big valve. The valve is basically the on-off switch for the well, where a rubber bladder slash gasket inside either blocks the exiting pipe, or it doesn't. It couldn't open properly because a sizeable piece of metal

had gotten stuck inside the valve. The valve is programmed to get about half open, and it could only manage a quarter. We think the metal was something from the well drilling process, and the drillers had figured out it was heavy enough that it would stay down in the well, which turns out to have been a bad assumption. So it was like a thing of drill bit or something.

Yeah, not sure. Because this valve couldn't open properly, while the pump was running, system pressure was too much for the well to overcome, so the water on the other side of the valve just stayed in place. Now, that part of the pipe also happens to be where we add chemicals to the water, which is hydrofluorosilic acid and chlorine gas.

Regulations require us to make sure tap water has a chlorine and fluoride residual, and since the well is going straight into the distribution system, we have to add those chemicals there. Yeah, of course, they don't need to do that now. The vaccinations are becoming mandatory. This is true, yes. You can see the HFS tank in the background,

or the line at least, it gets added to the water through a vacuum that the pump creates when water is being pumped into the system. Since there was no movement in the water, there was no vacuum adding the chemical. While some wells use the same concept to add the chlorine gas, this well has a pump that you can see in the picture. That's this guy.

Oh, boy. That chemical pump was running the entire time the well house pump was before the alarm was triggered. Oh, boy. Wait, wait, wait, wait. So when the guy comes into the chlorine pump, tell me the first thing he does is turn off the chlorine pump. No, maybe.

I don't know if that would have mattered. All right, so to the best of our knowledge, the alarm was triggered through the stagnant water in the pipe, getting so chlorinated that even the water in the waste drain on the floor was becoming saturated with chlorine. The floor drain in the main room of the building is connected with the floor drain in the chlorine room. It was wafting from that second floor drain to the gas detector,

which is the first alarm given to us that anything was wrong that night. By the time the gas could be detectable from that second floor drain, it had become super saturated in the pipe where the chemical was being added and is why an entire cloud came rolling along with the water. Jesus. Because the distribution system was using its pressure to push back on this water, the chlorine didn't travel in that direction where the sink is plumbed and why that didn't have any odor when it was running for over an hour.

So, oh boy. What did we learn? What did we learn? There's a new well alarm that's been programmed, so if there's a low flow, it gets shut off within half an hour instead of two hours later. It's also clear that chlorine gas is dangerous. Didn't know that one. But I guess we didn't learn that from the World War a century ago.

It's probably not going to be phased out anytime soon. Now this is cheaper than the alternatives, and this incident was only a near miss. Comforting. Somebody should probably refurbish that floor. I mean, it's better that the floor looks like that than somebody's fucking alveoli. That's a reminder. What even are the alternatives to chlorine? Do you use one of the noble gases or something?

I don't think that would. I mean, the purpose of chlorine is to kill microbes. I imagine to be something else that's also toxic. Silver? Yeah, probably turn everyone blue. Yeah, is there a downside? That's a good point. You could use, you could just start pumping the water supply full of,

what's the word, antibacterial stuff. You know, antibiotics, that's the word I'm looking for. Copper. We make the pipes out of copper. No, the whole thing, just pump copper through it. Pump copper through it. Yeah, just, it has to flow over like a couple of ingots of copper in a matrix. Nickel, I think.

I can't remember. With the World Asia Problem crew giving entire town heavy metal poison. Post in the comments what kind of metals you want us to pump into your town's water supply. Yeah, we do like instead of live shows, we do like a local event where we come to your town's water facility and we just pump metals. Spin the wheel of metals and metalloids. Oh, you get. Antimony.

Good luck. Yes. Maybe some, maybe some shit, what are all the rare earths that just explode on contact like a whole like a cesium. Sodium. Yeah. Well, that was safety third. Shake hands for danger.

I got through that quicker than I expected. Yeah. Yeah. That was a good episode. Thanks everybody. Next episode will be on the Tacoma Narrows bridge disaster. That's why I say that like it's a question. It's not a question.

Our next episode will be on the Tacoma Narrows bridge disaster. No, it's a statement of fact. It will be on the Tacoma Narrows bridge disaster. Oh, okay. When's Franklin 12? I need listen commercials. When are the international shipping on the shirts? Commercials.

Give me. Go listen to Lions led by donkeys. Go listen to Kiljays Bond. Go listen to Trash Future. Can I lay down now please? Yes, go. Okay. Bye everybody.

Bye. Bye.