Roman: This is 99% Invisible. I’m Roman Mars.
The thing about being wrong is that before you know you’re wrong, it feels exactly like being right.
Kathryn Schulz: If we knew that we were wrong, we wouldn’t be wrong. Nobody’s committing intentionally to a false belief about the world. If they are, they’re not wrong. They’re deliberately lying.
Roman: Even during the construction of the original Tacoma Narrows Bridge, which was to become the third longest suspension bridge in the world, it seemed like something was wrong. At least in hindsight, it seems like it should have felt that way, but that’s not how being wrong works.
KS: If you grew up like I did, watching the Warner Brothers cartoons….
RM: This is Kathryn Schulz, author of Being Wrong: Adventures in the Margin of Error.
KS: The Sunday morning cartoon moment where the roadrunner is dashing off the cliff and the coyote is following him and of course, the roadrunner can fly and the coyote can’t…. And there’s this great moment where he’s run off the cliff, but he has not yet realized that there’s no solid ground underneath him. And the moment when we’re wrong about something but before we realized it is like that moment. We think that our belief is rock solid. We think we have all of the facts in the world bolstering us.
RM: We feel like our giant suspension bridge is not going to collapse….
KS: We have not yet looked down and realized that. Whoops, that’s not the case.
RM: I know that sounds crazy, but even during its construction the deck of the Tacoma Narrows Bridge would go up and down by several feet with the slightest breeze. Construction workers on the span chewed on lemon wedges to stop motion sickness, but construction continued because the bridge had been designed specifically to withstand winds up to 120 miles per hour. So, everyone thought everything would be fine. Well, almost everyone. The original Tacoma Narrows Bridge designed by Clark Eldridge was pretty conventional for a suspension bridge, but it was later modified by Leon Moisseiff to be slimmer more elegant. The most notable change was the 25-foot lattice of stiffening trusses underneath the bridge on the original drawings, were replaced with an 8-foot solid steel plate girders. The new solid girder along the side that Moisseiff designed made for a much lighter, slimmer and more flexible bridge. It also caught the wind like a sail, but they didn’t know that. Moisseiff’s design was also 2/3 the price of the original Eldridge design and that fact ultimately won the day. Eldridge and other state engineers were said to have protested but it didn’t matter. The original Tacoma Narrows Bridge opened to the public on July 1, 1940.
John Marr: From the day it opened, it was prone to having these oscillations, these longitudinal waves of the bridge deck.
RM: That’s our master disaster, John Marr.
JM: I write on various murders and disasters and other sundry topics.
RM: He used to publish a zine called Murder Can be Fun and these sundry topics. He wrote about the Tacoma Narrows Bridge years ago.
JM: The workers on the bridge had nicknamed it Galloping Gertie and that came quickly kind of became the bridges unofficial name.
Roman: Even light winds caused the roadway to ripple with longitudinal waves some 5 feet high.
John: The State of Washington was concerned about this, but not like, intensely. So, they were like looking at various things to reduce the motion. They tried some tie-down cables and installing a damper and various other things, none of which had worked.
Roman: But again the roadbed seemed like it could handle the waves just fine.
John: They were very confident in the structural integrity of the bridge.
Roman: The Bridge was as solid as the air underneath Wile E. Coyote’s feet. When you watch film of the waves traveling down the bridge, it is stunning. And the fact that the bridge stayed open at all really illustrates how local governments and changed since 1940. That thing would never stay open today! If you were sitting in a car on the bridge when the waves were going, the cars in front of you would bob up and then disappear completely from view.
John: Almost like a thrill ride, people actually drive specifically for the feeling of riding on this bouncing bridge.
Roman: The ride ended just four months later.
(Reporter): Dawn of a fatal day and the wind begins to speak with a roar that no man can fail to hear.
Roman: It was clear early on the morning of November 7 that the gale force winds were having a greater effect on the bridge than ever before.
JM: Previously, these sorts of waves on the bridge had been like a fairly transitory. You know, you’d bounce up for a couple minutes but this was just going on and on, so they thought this could be problematical. Although they had seen actually deeper waves on the bridge.
RM: But then the movement changed.
JM: Things just got worse.
RM: The Bridge began to twist violently along the center line.
JM: And that became like, extremely violent. One end of the bridge deck was up at a 45-degree angle.
Male 1: In a 40 mile an hour gale the center span weaves like a ribbon the swinging bridge that you wouldn’t believe possible as the bridge gyrates right like a nightmare high above the river. Twisting, turning, curling!
Roman: By this time everyone had gotten off. The blunt solid edge of the bridge disrupted the flow of the strong wind causing one part to twist up, while the other section twisted down. And it continued this torsional back and forth for over an hour. So there was plenty of time for spectators to come watch. Including the bridge’s original designer, Clark Eldridge. A local camera store owner name Barney Elliot arrived on the scene and took the now famous color film of the bridges relentless gyrations.
Male 2: No structure of steel and concrete can stand such a strain. Steel girders buckle and giant cables snap like puny threads! There it goes! Engineers are divided as to the cause of the disaster. Some claim it was the use of solid girders, others differ. But whatever the reason, Tacoma will rebuild! This time a bridge that will not provide a super thrill in the news
RM: Before the collapse, bridge aerodynamics and structural failure due to torsion had scarcely been considered. Or maybe those lessons have been lost in the rapid evolution of more and more slender and longer bridges. But the failure caused the study of bridge aerodynamics to take off, and any bridges that were on the drawing board in 1940 were redesigned with more conservative, deep open trust deck structures. The lead designer Leon Moisseiff and his solid steel eye beams received most of the blame for that disaster. He never designed another bridge again. Due in no small part of the fact that he died three years later.
JM: No one was killed on the bridge. A few people were very lucky to get away with their lives. Because I mean, just imagine, you’re on this bridge and it’s twisting it at 45-degree angle and you’re trying to walk off in a fairly stiff wind. The only casualty was a dog.
RM: A local newspaperman named Leonard Coatsworth drove his car just past the east tower when the twisting started.
JM: It got bouncing so hard. He couldn’t control his car anymore.
Roman: The tilting bridge threw his car into the side curb.
JM: And he had his daughter’s dog, a Cocker Spaniel named Tubby with him.
RM: Coatsworth gets out of his wrecked vehicle and gets thrown face down on the curb.
John: The dog’s completely freaked out. He couldn’t get the dog out.
Roman: He hears the concrete cracking beneath him.
John: And he barely makes it to safety.
Roman: An engineering professor studying the bridge name Farquharson ventured out to get Tubby right when the bridge was about to fall into the sound. But when he reached into the car, Tubby bit him. The dog was just too freaked out to leave the vehicle. There’s an amazing film of Farquharson stumbling back as best he could sticking to that middle yellow line as the bridge rocked wildly along its center axis.
John: So Tubby was the only casualty and the poor guy, said: “I’m gonna have to tell my daughter this.”
Roman: Coatsworth was quoted immediately after the collapse saying, “With a real tragedy, disaster and blasted dreams all around me, I believe that right at this minute what appalls me most is that within a few hours I must tell my daughter that her dog is dead, when I might have saved him.”
This next bit is a completely unrelated addendum that will serve as a valuable life lesson to any 99% Invisible fan. Here’s John Marr again.
John: Several years ago, I went to the Portland Zine symposium to do a seminar on research-based zines.
Roman: Research-based zines, like research-based blogs or podcasts, have always been a bit in the minority. Anyway.
John: It was held in this building called the Michael Smith Memorial Student Union Building on the Portland State University campus. Very first thing I did is I got in front of the class and said, “Okay, this panel is being held in the Michael Smith Memorial Student Union Building. Does anyone know who Michael Smith was?” No one did. Michael Smith was the captain of the Portland State University College Bowl team. The College Bowl was a televised trivia competition matching teams from various universities throughout the country. And he led Portland State University to the championship, which is this is an incredible accomplishment. They’re beating out schools like Harvard and Yale and this is Portland State, this is a state school. This is not the type of school you expect to win something like this. I’m sure the Ivy League people were horribly embarrassed, and it was quite a big deal at the time. He also was suffering from Cystic Fibrosis and he would die three years after this. So, everyone agreed this was a good story. They asked me, “How you find out about this?” There’s a plaque in front of the building. My slogan is, “Always read the plaque.”
Roman: 99% Invisible was produced this week by me, Roman Mars A special thanks to John Maher of Murder Can be Fun and Alan Bellows of the website Damn Interesting. We are a project of KALW 91.7 Local Public Radio in San Francisco and the American Institute of Architects in San Francisco. Support for 99% Invisible is provided in part by TinyLetter; Email for people with something to say. My boy Mazlo has something to say, what do you have the say Mazlo?
Mazlo: Today, we get to talk about is Robots in Iron Man suits and stuff.
Roman: Robots in Iron Man suits. I would subscribe to that newsletter. It’s free, easy, minimal, powerful, the simplest way to write an email newsletter online at tinyletter.com. This program is distributed by PRX, The Public Radio Exchange making public radio more public. Find out more at prx.org and while I’m talking about PRX, I have to tell you about another podcast they produce called How Sound by The Genius Rob Rosenthal. If you’re a person who loves radio and is also the type of person who listens to the director’s commentary on DVDs then How Sound is the show for you check it out at howsound.org.
My man Sam Greenspan took off for a while to launch the TED Radio Hour at NPR but he’ll be back. You’ll be back, Greenspan! You can find the show and like the show on Facebook. I would like it if you would like us a tweet @romanmars. You can always catch up with us online at 99%invisible.org.