The Tacoma Narrows Bridge Collapse

On July 1, 1940, the Tacoma Narrows Bridge at Puget Sound in the state of Washington was completed and opened to traffic. From the day of its opening the bridge began to experience oscillations. Strange as it may seem, traffic on the bridge increased tremendously as a result of its novel behavior. Starting at about 7:00 on the morning of November 7, 1940, the bridge began undulating persistently for three hours. Segments of the span were heaving periodically up and down as much as three feet. At about 10:00a.m., something seemed to snap and the bridge began oscillating wildly. At one moment, one edge of the roadway was twenty-eight feet higher than the other; the next moment it was twenty-eight feet lower than the other edge. At 10:30 a.m. the bridge began cracking, and finally, at 11:10 a.m. the entire bridge came crashing down. Fortunately, only one car was on the bridge at the time of its failure. It belonged to a newspaper reporter who had to abandon the car and its sole remaining occupant, a pet dog, when the bridge began its violent twisting motion. The reporter reached safety, torn and bleeding, by crawling on hands and knees, desperately clutching the curb of the bridge. His dog went down with the car and the span - the only life lost in the disaster. 

There were many humorous and ironic incidents associated with the collapse of the Tacoma Bridge. When the bridge began heaving violently, the authorities notified Professor F. B. Farquharson of the University of Washington. Professor Farquharson had conducted numerous tests on a simulated model of the bridge and had assured everyone of its stability. The professor was the last man on the bridge. Even when the span was tilting more than twenty-eight feet up and down, he was making scientific observations with little or no anticipation of the imminent collapse of the bridge. When the motion increased in violence, he made his way to safety by scientifically following the yellow line in the middle of the roadway. The professor was one of the most surprised men when the span crashed into the water. 

One of the insurance policies covering the bridge had been written by a local travel agent who had pocketed the premium and had neglected to report the policy, in the amount of $800,000, to his company. When he later received his prison sentence, he ironically pointed out that his embezzlement would never have been discovered if the bridge had only remained up for another week, at which time the bridge officials had planned to cancel all of the policies. 

A large sign near the bridge approach advertised a local bank with the slogan "as safe as the Tacoma Bridge". Immediately following the collapse of the bridge, several representatives of the bank rushed out to remove the billboard.

Published courtesy of Professor Paul Goody, University of Oklahoma math department





An Eyewitness Account

of the demise of the Tacoma Narrows Bridge,

given by a Tacoma newspaper editor, Leonard Coatsworth

Just as I drove past the towers, the bridge began to sway violently from side to side. Before I realized it, the tilt became so violent that I lost control of the car... I jammed on the brakes and got out, only to be thrown onto my face against the curb. Around me I could hear concrete cracking. I started to get my dog Tubby, but was thrown again before I could reach the car. The car itself began to slide from side to side of the roadway. On hands and knees most of the time, I crawled 500 yards or more to the towers... My breath was coming in gasps; my knees were raw and bleeding, my hands bruised and swollen from gripping the concrete curb... Toward the last, I risked rising to my feet and running a few yards at a time... Safely back at the toll plaza, I saw the bridge in its final collapse and saw my car plunge into the Narrows."





A story of the

Tacoma Narrows Bridge

by Terry Grant

The second Narrows Bridge had to wait until the end of World War II to be built. Approximately four years were spent solving the problems that caused the failure of the first bridge. Financing the second bridge was also a problem, because many peacetime projects were being started and competition for available funds was keen. The Pierce County Commissioners agreed to underwrite $1,500,000 with a guarantee fund. This helped to sell the bonds and $14,000,000 was available for the new bridge.

The engineers were able to use the old piers as they were, except for the pedestals supporting the legs. These were raised eighteen feet to reduce the amount of salt spray that had caused the original towers to rust. The old pedestals were replaced anyway, as the legs of the new towers were 60 feet apart rather than the original 50 feet. This actually distributed the load borne by the piers more evenly.

Other parts of the original bridge which were utilized were the old anchorages for the cables. These were enlarged and somewhat redesigned, but about 65% was salvageable. Also most of the western approach was retained. This effected savings of more than three million dollars in the reconstruction price.

The new bridge was built of newer, lighter materials. . The new bridge has four lanes for traffic and two sidewalks. Even with two additional lanes, the superstructure weighs only 1.6 times as much as the old two-lane bridge. Between the lanes and sidewalks is a grillwork, through which the wind can be dissipated. The side trusses are 33 feet wide, but they are lattice type, not solid steel. The railing is grillwork, which allows the passengers to enjoy the view as well as the breezes to continue on their way. There are several sets of hydraulic jacks set at strategic places to absorb shocks and make it almost impossible for the bridge to oscillate.

The new bridge was completed in 29 months and was opened to the public by Governor Langlie on October 14, 1950. It was rather sad to watch the ferries head up the Sound after their last trip. Riding ferries can be fun. It gives you a chance to make friends of toll collectors and fellow commuters.

The new bridge was an instant success. First day tolls amounted to $11,541.39. This record stood until a Sunday in August, 1964. Tolls were removed thirteen years ahead of schedule, in October 1965. The first person to go through toll-free was a truck driver, jubilant over the $7.00 he saved. Governor Evans presided at the ceremony celebrating the removal of the tolls. Average bridge traffic during 1964 was 8,000 vehicles per day. (It was predicted when the bridge was built in 1950 that it might reach 5,800 by 1977.) In July, 1966, an average day's vehicles came to 17,665. By 1970 the July average had reached 24,326, and in 1974 it was 28,897.

If Harold Ickes, Roosevelt's Secretary of the Interior, were to pause and look across the Narrows today, he would see the answer to his question of 1938, "Who would want to build a bridge to that wilderness?"

SOURCES: Tacoma News Tribune, November-December, 1940
Brochure on the original bridge written by National Youth Administration
Brochure on the second bridge by Washington Toll Bridge Authority
Miscellaneous clippings furnished by the Toll Bridge Authority
Personal recollections of former Toll Collector Bill Leith





On The Virtues Of The Right Equipment

Kerry Bingham had been drinking with several friends when one of them said they knew a person who had bungee-jumped from the Middle of the Tacoma Narrows Bridge. The conversation grew more heated and at least 10 men trooped along the walkway of the bridge at 4:30 a.m. Upon arrival at the midpoint of the bridge they discovered that no one had brought bungee rope. Bingham, who had continued drinking, volunteered and pointed out that a coil of lineman's cable lay nearby. One end of the cable was secured around Bingham's leg and the other end was tied to the bridge. His fall lasted 40 feet before the cable tightened and pulled his foot off at the ankle. He miraculously survived his fall into the frigid waters of the Tacoma Narrows and Puget Sound and was rescued by two nearby fishermen. "All I can say," said Bingham, "Is that God was watching out for me on that night. There's just no other explanation for it." Bingham's severed foot was never located.

Bungee Jumper, 1997 Darwin Awards Nominee, Confirmed True by Darwin (13 July 1997, Virginia) Eric A. Barcia, a 22-year-old Reston, VA resident, was found dead yesterday after he used bungee cords to jump off a 70-foot railroad trestle, police said.

The fast food worker taped a number of bungee cords together and strapped one end around his foot. Barcia had the foresight to anchor the other end to the trestle at Lake Accotink Park, and he even remembered to measure the length of the bungee cords to make sure that they were a few feet short of the 70 foot drop. He proceeded to fall headfirst from the trestle, and hit the pavement 70 feet below several seconds later.

Fairfax County police said "The stretched length of the cord that he had assembled was greater than the distance between the trestle and the ground." Perhaps the deceased fast food worker should have stuck to the line, "Do you want fries with that?"

From the Darwin Awards



 

The Tacoma Narrows Bridge Incident

by Christopher Lansdown

As background, there was a bridge built over the Tacoma narrows, which is to the best of my knowledge an area of water (the Puget Sound, specifically) which is reasonably narrow and is located in Washington state in the US. A bridge was built over these narrows which had the unfortunately property of being of the right proportions to resonate with the wind. The resonation was so bad (or good) that the oscillations were too great for the support structures of the bridge and the bridge eventually collapsed. This was in the 1940s, bridge design has gotten much better, partially as a result of this. (This story is also a pretty standard explanation of resonance in physics class.)

The part of the story that I'm interested in is the part about the reporter who drove onto the bridge when everyone suspected (rightly) that it was about to collapse. The basics of the story are this:

  1. The reporter heard that the bridge was going through its undulations much stronger than it ever had previously.

  2. The reporter decides that he's going to go check it out.

  3. The reporter grabs his daughter's pet dog and sticks him in the car.

  4. The reporter drives to the bridge.

  5. Despite warnings not do, the reporter drives out onto the bridge.

  6. The reporter stops partway out (nearly half-way), then gets out of his car.

  7. The reporter is thrown to the ground. He then crawls to the outside of the bridge, where the undulations are at there worst (sections of the bridge were doing partial rotations about the length of the bridge as well as bobbing up and down, so the partial rotations had the worst effect towards the edges).

  8. He manages to crawl off of the bridge on his hands and knees and shortly afterwards the bridge collapses, destroying his car and killing his daughter's dog.

Ok, now let's examine these step by step:

  1. The reporter heard that the bridge was going through its undulations much stronger than it ever had previously.

    This is pretty reasonable. It is a reporters job to explore news so that they can describe it to others, so it's natural for this reporter to be told about an event.

  2. The reporter decides that he's going to go check it out.

    Again, this is a natural action for a reporter. Nothing is at all strange about a reporter deciding to actually visit the scene of a news event.

  3. The reporter grabs his daughter's pet dog and sticks him in the car.

    Ok, this is where things start to get strange. Why on earth would one bring a dog on a reporting trip? It's not like the guy was going on an overnight trip and couldn't ask a friend or neighbour to feed the dog. I assume that this dog wasn't a specially trained "new dog" since it was actually his daughter's pet. As far as I can tell he simply decided that his reporting didn't have enough cocker spaniels in it. Even so, doesn't it break some sort of etiquette to go taking other people's pets on trips without asking? I know that I would be annoyed at my father if he grabbed one of my pets and ran off to a collapsing bridge without asking me first.

  4. The reporter drives to the bridge.

    Again, this is another reasonable thing to do. When you're going somewhere close, driving is as good a way as any.

  5. Despite warnings not do, the reporter drives out onto the bridge.

    Now we're back to the unexplainably stupid actions. The bridge is waving up and down so badly that parts of it are disappearing from view. It's waving worse than ever. Does this really sound like a good way to spend one's evening?

    Ok, let's assume that going out onto the bridge is a good idea. Why on earth should he drive out? The best case scenario is that he drives back and uses up gasoline needlessly. The worst case (which did happen) was that he lost the car. Frankly, the benefits don't seem to outweigh the risks. Cars are expensive.

    Then there's always the question of the dog. Even if we assume that driving out was a good idea, and further assume that doing so in his car was a good idea, would it have been that inconvenient to have tethered his dog somewhere safe? I know that animals weren't considered as important back then, but still, everyone knew that being in bridge collapses leaves dogs in a state that tends to make their little-girl owners cry. (Incidentally, this is the best reason for the development of the aibo - this way those who would abuse their dogs can get aibos instead. This way when they beat them the aibo won't mind and when the forget to feed their aibo it won't even notice. If only there were aibos back then so that he could have left his daughter's aibo on the bridge rather than her dog!)

  6. The reporter stops partway out (nearly half-way), then gets out of his car.

    Just one question: doesn't this guy know how to shift his car into reverse?

  7. The reporter is thrown to the ground. He then crawls to the outside of the bridge, where the undulations are at there worst (sections of the bridge were doing partial rotations about the length of the bridge as well as bobbing up and down, so the partial rotations had the worst effect towards the edges).

    Alright, he's scared, it's a dangerous situation, etc. It's pretty obvious that the edges of the bridge are moving more violently than the inside. Isn't it human nature to crawl towards the least violent part of the bridge?

  8. He manages to crawl off of the bridge on his hands and knees and shortly afterwards the bridge collapses, destroying his car and killing his daughter's dog.

    At least this guy got out safely. How he managed it, considering the number of really dumb things he did previously, I don't know, but this at least was a good thing.

I think that the lesson that we all learned from this was: if you don't plan to treat your pets well, buy a robotic version instead. Currently you can buy robotic fish, birds, and dogs. I'm sure that cats will be on the way soon. Please, if you have impulses to go into dangerous situations carrying other people's pets (or even your own), go to Wal-Mart and buy a robotic version of the same to take with you. I'm sure that if you don't have enough money to afford a robotic version, God will forgive you for stealing it. Just don't bring the real one.


5:23 PM on February 21, 2001.
All works on this site by Christopher Lansdown are placed in the public domain.








 

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Revised: September 24, 2003 10:22:04 AM .