Talk:Tacoma Narrows Bridge (1940)
|This is the talk page for discussing improvements to the Tacoma Narrows Bridge (1940) article.|
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- 1 Creation of this article
- 2 Bridge Length
- 3 Reliable source for Atom Man
- 4 I would rename article to Tacoma Narrows Bridge (original) (1940)
- 5 Galloping Gertie
- 6 Trivia
- 7 References in popular culture
- 8 Collapse image mirrored, replacement showing correct orientation found
- 9 Collapse; new information needs to be added, etc.
- 10 History of the Tacoma Narrows Bridge
- 11 The Collapse of the Entire Bridge ???"
- 12 Unexplained deletion of content
- 13 2009 - Russia - same design fail
- 14 Aeroelastic Fluttering vs. Resonance
- 15 Mechanism ?
- 16 Fluttering = Resonance
- 17 Resonance
- 18 Nice pics
- 19 Reversed Photo
Creation of this article
This article was created as a split from the Tacoma Narrows Bridge article as the result of a discussion on that talk page. Anyone considering a move or a merge of information in the Galloping Gertie article may want to review that previous split/keep discusion (July August 2008). - PennySpender1983 (talk) 05:07, 16 August 2008 (UTC)
The article states that the 1940 Tacoma Narrows Bridge length is 4,500 ft. At the end of the article it reads that the (now) Tacoma Westbound Bridge "is 5,979 feet (1822 m) long — 40 feet (12 m) longer than Galloping Gertie." There is a discrepancy between the compared lengths of the bridges. Can this be resolved to insure the integrity of the article?
- You're right, it's definitely comparing the two different structures. However, if the 1950 Tacoma Westbound Bridge "is 5,979 feet (1822 m) long — 40 feet (12 m) longer than Galloping Gertie." that would imply Galloping Gertie is about 5,939 feet (1810 m) in length. The article gives the length of Galloping Gertie as 5,000 feet (1524 m) leaving 939 feet (286 m) unaccounted for. 22.214.171.124 (talk) 15:48, 22 August 2008 (UTC)
- A little late here, but chiming in anyways. The "unaccounted" 939 feet is the length of both the east and west cable anchorages, and approach spans, combined. The side spans and main spans of both bridges both total 5,000 feet (1,100 feet and 2,800 feet respectively for both). However, the cable anchorages on the first bridge were shorter in length. Source: Bridging the Narrows by Joe Gotchy (1990)Srosenow 98 (talk) 11:21, 9 April 2009 (UTC)
- For Pete's Sake! You need to state these lengths: A) The overall lengths of the suspension bridges that are involved, excluding the length of all approach bridges, B) The lengths of the main spans of the bridges involved. This latter is the distance of the roadway between the two steel towers that hold it up. That's the span across the wide part of the water. For example, when giving the length of the Golden Gate Bridge, the length of the steel arch approach bridge on the north side (in Marin County) is not included.
- Then, when it comes to the length of the world's longest suspension bridge, for example, what counts is the length of the main span. That record was held by the Golden Gate Bridge from 1937 until about 1964, when the Verrazano Narrows Bridge in New York City was completed. In the meantime, the Mackinac Straits Bridge in Michigan was completed. Its main span, plus its two (unusually long) side suspension spans, gave a total length of longer than that of the Golden Gate Bridge. However the main span length was what counted.
- The record for the length of the main span has been exceeded several times since 1964, by various suspension bridges in England-Wales and in Japan. So, that record has not been held by the United States since sometime around 19126.96.36.199.222 (talk) 04:57, 17 November 2009 (UTC)
Reliable source for Atom Man
Actually, the given link only mentions the film referred to here obliquely, does not support the given statement. Unless there's a reliable source mentioning which bridge is shown, it's not sourced. Tedickey (talk) 11:16, 20 October 2008 (UTC)
- you are right, we need a more reliable reference. However, I doubt we can find one Diego Torquemada (talk) 13:06, 20 October 2008 (UTC)
I would rename article to Tacoma Narrows Bridge
It should be changed to reflect that the Galloping Gertie nickname was assigned to the bridge by its builders in the construction phase, not by area residents. It's also mentioned in Catastrophe to Triumph: Bridges of the Tacoma Narrows. (ISBN 0-87422-289-3) that the "Galloping Gertie" name was common in bridge construction, especially in bridges that reacted in winds as did the original Tacoma Narrows Bridge. Srosenow 98 (talk) 11:07, 14 May 2009 (UTC)
- The References in popular culture (trivia) section has been tagged as trivia since August 2008 and no one has found a way to relocate relevant items into appropriate sections. Probably because there are no appropriate sections to relocate the material into. Also some of the material is unsourced and has been tagged as citation needed since October 2008. If anyone wants to source the material and move it to an appropriate place than they are welcome to go there. Don't just replace it without adding appropriate citations and ensuring it is appropriate for the article. It is the responsibility of the person adding or readding the material to cite the material show it is relevant. A new name 2008 (talk) 23:15, 31 May 2009 (UTC)
References in popular culture
The Canadian rock group the Tragically Hip made a reference to the collapse of the bridge in its song "Vaccination Scar."
Footage of the bridge before and during the crash was used in Chapter 1 of the 1950 serial Atom Man vs. Superman. Leonard Coatsworth's car is seen in this footage and was worked into the script as being a car with a woman driver stranded inside.. Superman held the bridge steady long enough for a policeman to rescue the woman, and then the bridge collapsed after he flew away.
The bridge footage is also the basis for a Pioneer car stereo commercial
As I see it, that is the purpose of an encyclopedia is to understand the subject of the article. Can you explain why you feel this material belongs in this article and how it contributes to the understanding of this bridge? This information does not tell me anything about the bridge, it tells me about the Tragically Hip, Atom Man vs. Superman and a Pioneer car stereo advertisement. If this information is helpful to the understanding of those subjects then that is where this information belongs. If it can be shown that this information aids in the understanding of the Tacoma Narrows Bridge then it belongs here. A new name 2008 (talk) 13:30, 1 June 2009 (UTC)
- The problem I see with your logic, is that it seems to be a case of WP:IDONTLIKEIT. The Tacoma Narrows Bridge is the most famous bridge collapse historically speaking and that fact has earned its place in popular culture. Also, in the same token, if it appears in an episode of Superman, or appeared in a Pioneer car commercial, citations wouldn't be necessary since the videos themselves serve as reference. It should also be noted that the Pioneer car commercial in the mid-1990s was nominated for a Clio Award due to the use of the Barney Elliott/Harbine Monroe film of the bridge in its death throes. In my view, the deletion of this material is detrimental to the article since it was pretty evident it had a pretty powerful impact.
- Furthermore, the lyrics to Vaccination Scar can be referenced here at the official MTV website  and the reference for the Superman entry can be seen on the [IMDB entry's Trivia page]
- Also, how would one understand the cultural impact and understanding of the Tacoma Narrows Bridge in popular culture without this information present? As soon as I can, I'm re-inserting this information into the article.Srosenow 98 (talk) 00:11, 7 July 2009 (UTC)
Collapse image mirrored, replacement showing correct orientation found
I've taken the task of searching for a web-resolution screenshot of the same image seen here , and this is what I've located. This is exactly how the image appeared on the original color film, and is also exactly how the collapse was photographed by James Bashford. I think all we need to do is replace the poor-quality black and white with this one. Since I'm unsure on the steps necessary to replace a file on Commons (and here, likewise) to overwrite the black-and-white version, I won't continue, but I do believe we should replace the poor-quality black and white photo with this one.Srosenow 98 (talk) 11:54, 4 June 2009 (UTC)
- This doesn't show the whole bridge. I can see placing this image later in the article where it's talking about the collapse, though. - Denimadept (talk) 14:11, 4 June 2009 (UTC)
- The film footage at the moment of collapse (this image here) as well as the Bashford photo never showed the whole bridge in the first place, and no photos exist that show the whole bridge itself at the moment of collapse (with exception of a rare photo taken from near the west approach viaduct, and that photo suffers from light-leak). The point I was trying to make is that we should replace the black-and-white image of the collapse that's already in the article, with this one, for two reasons. One, is that it's taken from the same film (at the same moment), which was originally shot in color, and two, it shows the correct orientation of the image (not being flipped horizontally).Srosenow 98 (talk) 19:46, 4 June 2009 (UTC)
Collapse; new information needs to be added, etc.
Going back to this image here for a second, I'm going to illustrate a fact not stated in this article.
At the time the Tacoma Narrows Bridge collapsed, there was more than one car on the mainspan. These facts are per Catastrophe to Triumph: The Bridges of the Tacoma Narrows (Richard S. Hobbs (2006) WSU Press. (ISBN 0-87422-289-3). At just after 10AM November 7, a loaded log truck was driven across the west approach, and stopped on the main span of the bridge just east of Tower #4 (the main tower on the west side) due to the violent corkscrew torsional motion which began at 10:03AM. At the same time, a delivery van owned by Rapid Transfer Company started its trek from the Tacoma-side of the bridge headed towards Gig Harbor. The twisting motion caused the log truck and delivery truck to van to tip over. The log truck spilled its load all over the bridge (and also over the sides of it), and its driver got out and fled across the west side span. The occupants of the Rapid Transfer Company van, Walter Hagen and Ruby Jacox, both fled the scene as well and survived.
The image above illustrates the Rapid Transfer Company's van in its plunge to the Narrows, along with the initial 600-foot west section of the mainspan. The van can be seen in the image headed nose-first into the Narrows just ahead of the collapsing section of roadway.
I've re-uploaded the image in its original resolution from the original 16mm film, to illustrate this. In light of this, I suggest a partial or total rewrite of the collapse section of this article, or perhaps a fork of this article into another article titled Tacoma Narrows Bridge Collapse, that could have this information plus the sequence of events before, and on November 7, 1940 leading up to its collapse.
History of the Tacoma Narrows Bridge
Two of the eastern approach sections from the original bridge were re-used in 1944 for the suspension bridge over the Liard River at mile 496 on the Alaska Highway (aka the "Alcan"). Interestingly enough, this bridge was used as part of the study for the book "In the Wake of Tacoma". Rvuuld (talk) 23:28, 3 October 2009 (UTC)
The Collapse of the Entire Bridge ???"
It is stated several times in this article about the original Tacoma Narrows Bridge that the ENTIRE suspension bridge collapsed. It is also said that the ENTIRE bridge had to be reconstructed. These are not a true statements, and they needs to be corrected. So many people overlook the fact that the two tall steel towers of this bridge were undamaged and did not collapse. Furthermore, people disregard the foundations for the two towers for the bridge, which were constructed with the expenditure of a large amount of money and a huge amount of labor, probably using caissons. Blinding your eyes to these is actually a gross insult to the men who worked very hard to dig and install the foundations of the bridge.
The part of a bridge that includes its foundations and the vertical supports that rise from them, up to the bottom of the roadway structure, are called the "substructure" of the bridge, and what comes above this is called the "superstructure". What actually collapsed on the Tacoma Narrows Bridge was part of its superstructure, including all of its main-span roadway. After the collapse of the roadway in November 1940, all of the bridge's substructure was left intact (did not collapse), plus its two steel towers, plus the two suspension-bridge cables.
Elsewhere in this article, it is said that the two cables were removed and used as scrap iron that was used during World War II, when steel was in great demand for ships, tanks, etc. However, I have read elsewhere, years ago, (and you'll have to look up a source) that when the Tacoma Narrows Bridge was rebuilt, that it used the same foundations and towers that had been built for the first bridge. This makes one heck of a lot of engineering and economic sense! If you think to the contrary, you need to find out whatever happened to the original foundations and the steel towers, and why.
Also, I have never been a resident of the Tacoma area, but I did drive across the Tacoma Narrows suspension bridge in about 2003, and that bridge was clearly more than two lanes wide. It was at least four lanes wide, and it was set up as an expressway. Something needs to be written about how and why the two-lane bridge of 1940 became the four-lane bridge of 1950. I believe that this happened in the redesign and rebuilding of the bridge. By about 1947, they knew that they new bridge needed to be wider -- simply since the population of the Seattle-Tacoma-Bremerton area had exploded during WW II. Lots of people came from other parts of the country to work in the Boeing Aircraft plants and in the various shipyards that grew tremendously during WW II, especially to support the naval base at Bremerton. Hundreds of thousands of people moved there, and after the war was over, lots of them did not want to leave. The same thing happened in many places in California, but especially San Francisco-Oakland, Los Angeles-Burbank-Long Beach, and in San Diego County. Likewise in areas of Texas, Florida, Georgia, Virginia, etc.188.8.131.52 (talk) 05:42, 17 November 2009 (UTC)
- A couple of things. (1) Do not, ever, change another person's comments in any way, including grammar and spelling. (2) the towers were damaged in the collapse, so yes, the entire bridge had to be replaced. - Denimadept (talk) 06:47, 17 November 2009 (UTC)
- More, if you disagree, you're welcome to provide references. Others have done this. Otherwise, you might well be mis-remembering what you read "years ago". - Denimadept (talk) 06:50, 17 November 2009 (UTC)
- One last thing. I feel like I've been a bit hard on you, but I don't mean it to feel like that. What I intend is that you consider what you're writing carefully before you modify existing text. While WP:BOLD is the guideline, you've got to consider that this stuff, and especially this article about a famous engineering failure, has been gone over by many people over a period of years. To suddenly come up with a drastically different POV w/o references to back that position up, is going to be rejected w/o mercy. - Denimadept (talk) 06:56, 17 November 2009 (UTC)
Unexplained deletion of content
In the last day, both User:Upscayled and User:184.108.40.206 have been removing content from the article without much explanation. The version before the edits is here. The net effect of the edits is here.
In an edit comment, User:Upscayled claimed that the material removed was unsubstantiated. However, the diff shows that some of the material was reworded (e.g., "Moisseiff was able to justify stiffening the bridge with" was replaced with "Moisseiff argued for"). Further, the latest edits have confusing summaries: User:Upscayled did not revert User:220.127.116.11, nor did User:18.104.22.168 revert User:Upscayled --- the net effect is that both users are removing material, not reverting each other.
I'm still willing to assume good faith that these users are trying to improve the article. However, I would like a more detailed explanation of the edits here on the Talk page. —hike395 (talk) 07:24, 16 March 2010 (UTC)
- No response yet: I've reverted the changes, but I'm happy to discuss them. —hike395 (talk) 09:09, 17 March 2010 (UTC)
Sorry I'm new, not sure how this 'talk' thing works. Basically, the resonance hypothesis was disproved BEFORE the bridge even collapsed so there is no justification for its existence in this article! Cheers —Preceding unsigned comment added by 22.214.171.124 (talk) 20:55, 17 March 2010 (UTC)
- It's still worth including so no one will come around later and try to argue it. It's part of the history. - 126.96.36.199 (talk) 21:38, 17 March 2010 (UTC)
2009 - Russia - same design fail
The same design fail seems to be in a recently constructed bridge in Russia. http://www.youtube.com/watch?v=WEQrt_w7gN4 —Preceding unsigned comment added by 188.8.131.52 (talk) 21:53, 21 May 2010 (UTC)
- That does look like a similar failure mode. (looks) Well, that was easy to find: Volgograd Bridge. Looks like we don't have much information yet. - Denimadept (talk) 15:26, 22 May 2010 (UTC)
Aeroelastic Fluttering vs. Resonance
From the article:
In many physics textbooks, the event is presented as an example of elementary forced resonance with the wind providing an external periodic frequency that matched the natural structural frequency, even though its real cause of failure was aeroelastic flutter.
This movement inserts energy to the bridge during each cycle so that it neutralizes the natural damping of the structure; the composed system (bridge-fluid) therefore behaves as if it had an effective negative damping (or had positive feedback), leading to a exponentially growing response. In other words, the oscillations increase in amplitude with each cycle because the wind pumps in more energy than the flexing of the structure can dissipate, and finally drives the bridge toward failure due to excessive deflection and stress.
Resonance is the tendency of a system to oscillate at maximum amplitude at certain frequencies, known as the system's natural frequencies. At these frequencies, even small periodic driving forces can produce large amplitude vibrations, because the system stores vibrational energy.
First off, the footnote links to a 1991 article that makes no reference to any kind of "fluttering," aeroelastic or otherwise. is this a case of WP making some precatory, fiat-like conclusion -- "If I say so it shall be so!" ... ? Is aeroelastic fluttering any different from resonance? Is it even a legitimate theory? Is there really so much discord among textbooks?
Let's be clear: A physical event took place. It happened to be caught on film. Various theories have been put forth to explain the event, NONE OF WHICH can change the nature of what actually took place on that day. Guess what wikipedians, this is always the case for every theory of anything that has happened in the history of the universe. So when you say, "even though ... I really know ... what happened ... and my theory is the be all and end all," you might consider how fleeting is the glory of such theories. Dynasteria (talk) 12:16, 5 July 2010 (UTC)
- We require references. If the references say such and so, then that's what we include. If you have alternate references which say otherwise, you can add text which say something like "other sources say yadda yadda", and include those references. You can't just wave your hands and make it otherwise. - Denimadept (talk) 15:31, 5 July 2010 (UTC)
Would you please point out the references that support the aereolastic flutter theory? I'm not an engineer, nor do I pretend to know anything about the subject.Dynasteria (talk) 01:54, 6 July 2010 (UTC)
- If you want to learn about a modern method to estimate fluttering on bridges I would point you to:
Chen, X., Matsumoto, M. and Kareem. A. (2000), "Time Domain Flutter and Buffeting Response of Bridges", Journal of Engineering Mechanics, ASCE, Vol.126, No.1, pp.7-16. http://www.nd.edu/~nathaz/journals/(2000)Time_Domain_Flutter_and_Buffeting_Response_Analysis_of_Bridges.pdf
Chen, X., Matsumoto, M. and Kareem, A. (2000), "Aerodynamic Coupling Effects on the Flutter and Buffeting of Bridges", Journal of Engineering Mechanics, ASCE, Vol.126, No.1, pp.17-26. http://www.nd.edu/~nathaz/journals/(2000)Aerodynamic_Coupling_Effects_on_Flutter_and_Buffeting_of_Bridges.pdf
And the classic reference on the topic: Emil Simiu, Robert H. Scanlan Winds Effects on Structures: Fundamentals and Applications to Design http://www.amazon.de/Winds-Effects-Structures-Fundamentals-Applications/dp/0471121576/ref=sr_1_7?ie=UTF8&s=books-intl-de&qid=1278431785&sr=8-7
Those are some of the state-of-the-art references in order to learn about bridge fluttering. I did my master thesis on bridge aeroelasticity. I know what I am talking about. Diego Torquemada (talk) 16:01, 6 July 2010 (UTC)
- Start by reading the entire article. Then start through the references, with the first one. You can't argue unless you're already in possession of what's in the article. - Denimadept (talk) 02:11, 6 July 2010 (UTC)
You must be joking. Or else you are being malicious. I can't demonstrate what isn't there, while you can easily point to what you see. There is simply NO support or reference or citation offered for aereoelastic fluttering in the context of the Tacoma Narrows Bridge. Go ahead, prove me wrong and I will be forever grateful.Dynasteria (talk) 02:37, 6 July 2010 (UTC)
If no one refutes what I have to say here within a reasonable time period I will make some changes in the combative tone of the article. I have nothing against any supported theory, but I do not like it when an encyclopedia article casts aspersions on any number of scientists in favor proponents of a new theory. All that need be said here is: "Various theories have been put forth, among them etc. The most comprehensive appears to be X, while Y and Z do not take ABC into account."Dynasteria (talk) 02:52, 6 July 2010 (UTC)
- None of the above. It's right there in the first reference, as well as several of the others. - Denimadept (talk) 03:25, 6 July 2010 (UTC)
- Further, this wasn't studied only from the film. It was studied by model as well, and it was studied by many people before they built the replacement bridge. And by many people in the sixty years since then. - Denimadept (talk) 04:28, 6 July 2010 (UTC)
OK, thanks. I found a searchable version of the Billah/Scanlon article and the word "aeroelastic" is used 4 times, 1 of which is in the notes. "Flutter" is used a bunch of times. (So I admit I was wrong there.) "Aeroelastic flutter" is not used. Anyway, what I object to is the combative tone set up between resonance theory and aeroelastic theory. The implication is that the latter has conclusively and overwhelmingly replaced the former, all based on one article. Look at it this way, academicians are constantly defending their theories by putting down other people's theories. How did you get involved and why are you so partisan?Dynasteria (talk) 13:23, 6 July 2010 (UTC)
- I don't need to answer this, but I will. You've noticed this in one reference. I've seen it in several. There are many people watching this article besides me who will revert you if you try to change this based on your belief that the previous answer is correct. This has been studied for seventy years now by engineers from students to post-PhDs as I understand it, and the conclusive answer has been given in the article, as have the theories which were proven wrong beforehand. This is explained in the article. As far as I can tell, this is explained in the first reference, as well as being stated by others. If you have an issue with them, feel free contact the authors of the references involved. Or become an civil engineer and come to understand the data. I'm not one, so I just go by what the references tell me. - Denimadept (talk) 14:19, 6 July 2010 (UTC)
The topic is very good at propagating the confusion. See also Talk:Aeroelasticity#How_is_this_not_a_form_of_resonance.3F
Trying to add clarity, I added this to Kármán_vortex_street#See_also
- Aeroelastic Flutter - where the self-resonance of the solid object dominates, eg flapping to give +/- Lift (force) resulting from angle of attack
Fluttering = Resonance
The difficulty of deciding between Fluttering vs. Resonance is that fluttering is resonance, and resonance is fluttering. I have yet to see any definition that puts even a gnat's whisker between the two.
- "wind providing an external periodic frequency that matched the natural structural frequency"
No. The wind can provide a steady-state energy which can 'pump' the resonance - it doesn't need 'tuned gusts' !
A violinist doesn't have to wiggle the bow at 440 Hz to produce 'Middle A' (IIRC !) The length, tension and maybe mass (?) of the string determine the frequency. There is a non-constant, non-linear, Hysteresis in the coupling between bow and string. Stick-slip friction. Sliding friction is less than Static friction. When the bow first touches the string they move together, until the restoring force of the string overcomes the Friction, and the string slides back until it matches the speed of the bow again, when the rosin helps it stick, and the cycle starts again. See Hurdy-gurdy for a string driven by a constant-velocity wheel, removing the human factor.
It's like the Escapement of a clock or watch. Converts a steady source of energy to a resonant oscillation.
Likewise, the power supply for a Laser does not need to provide energy at the laser frequency - a CO2 laser can be driven by a Radio frequency source, a Nitrogen laser can be driven by a Direct current source and untuned Spark gap, a tunable visible Dye laser can be pumped by a fixed-wavelength laser etc
A leaf or branch dangling in a stream can resonate. Aspens trembling in the wind ...
It's pretty meaningless to tell us
- "For Reynolds Numbers greater than 1000, the Strouhal number is approximately equal to 0.21. In the case of the Tacoma Narrows, D was approximately 8 feet (2.4 m) and S was 0.20."
So what ? 0.20 = 0.21, near enough ? How 'approximately' - what are the Error-bars Uncertainties Tolerances ? Are they constant with respect to temperature, load, wind-speed, amplitude, air-pressure, humidity ? What is the mutual coupling coefficient of the (Vortex shedding or) Vortex-induced vibration and the bridge-in-still-air resonance ? What are the Q factor of the resonances ?
- See the discussion two sections up, and the article itself. - Denimadept (talk) 06:05, 17 December 2010 (UTC)
- That's what prompted me to write this ... duh !
- Came back after reading + viewing
- Surely damping is a cure for resonance, not aerodynamics ?
- It's as though you're arguing the sky is not blue, it's 'bright blue'. It is both.
- --184.108.40.206 (talk) 05:03, 10 June 2013 (UTC)
In the writing of this Wikipedia page, it is clear that a confusion has occurred, both with the intentions of an article used as a reference, and the implications of basic science. The article states that ‘In the case of the Tacoma Narrows Bridge, there was no resonance.’ This statement is reached on conclusion that 2πfs ≠ ω. This is true, however it only concludes that resonance was not caused by vortices in the von Kármán vortex street.
In the referred to material, Billah and Scanlon state in equation (5) that aerodynamic (“flutter”) coefficients are functions of K, where K relies on omega, the circular frequency of oscillation. Equation (3) shows how as an oscillator, the effects can be described as reliant on ‘omega-n’ which is the natural frequency.
This shows that aerodynamic flutter relies on the natural frequency of a system, so by extension we cannot single out resonance in conjunction with aerodynamic flutter. The two must be able to co-exist, and if they do, they affect each other. Therefore, putting it as a ‘vs.’ case is totally ridiculous. It is not ‘one phenomenon or the other’, it is ‘one phenomenon and possibly the other’. The question we are left with is ‘Did resonance occur?’
So did resonance occur? Well first of all, what is resonance? The article we seem to be using states resonance as being “whenever a system capable of oscillation is acted on by a periodic series of impulses having a frequency equal to or nearly equal to one of the natural frequencies of oscillation of the system, the system is set into oscillation with a relatively large amplitude.” A simpler explanation of resonance is ‘excitation frequency/natural frequency=1’. That is the technical definition used by vibration engineers. Basically, resonance did occur if the excitation was equal to the natural frequency.
Now, please don’t say ‘but there was no excitation’ for then there was no oscillation. The article used says “It was characterized as an aerodynamic self-excitation effect”. If the excitation caused by the aeroelasticity was equal to the natural frequency, then resonance did occur. I’ll leave it up to the article used throughout to tell you that there could be resonance: “Could this be called a resonant phenomenon? It would appear not to contradict the qualitative definition of resonance quoted earlier, if we now identify the source of the periodic impulses as self-induced, the wind supplying the power, and the motion supplying the power tapping mechanism.”
It's also worth noting that the purpose of the article referred to is to demonstrate the need for accuracy in writing textbooks, and the article's conclusion is that physics textbooks should 'offer the next generation of students subtler, more complex, and correct explanations'. The intention is not to disprove resonance in a particular case and it certainly does not do so. — Preceding unsigned comment added by 220.127.116.11 (talk) 01:45, 23 February 2012 (UTC)
In http://lib.washington.edu/specialcollections/collections/exhibits/tnb/aftermath there are some nice pics about the TN brigde. I have written them. I hope they will allow us to post some pics to the page.
The color film frame from the bridge collapse movie appears to be reversed. The still appears to have been taken to the left of the collapsing bridge, while the motion footage included on this page is taken from the right.2001:558:6011:B:5051:F65D:36F0:7127 (talk) 22:48, 3 September 2013 (UTC)
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