Daggers Posted 15 August 2006 Share Posted 15 August 2006 I am afraid to say that performance gave me no confidence at all. Are there any Structural Engineers that can tell me what "Vibrating Feet Frequency" is? Interesting point, How come we can risk a possible 32,000 odd fans jumping up and down going crazy after a goal or a series of goals in quick succession and not be able to hold a pop concert when its going to be the same sort of scenario anyway? Maybe thats why the crowd are so quiet and the stewarding so strict on standing, we could send the place crashing to the floor if we over-do it I'm guessing he is refering to resonance - "when one object vibrating at the same natural frequency of a second object forces that second object into vibrational motion." The common example used is the Tacoma Narrows bridge disaster. I'm at a loss to understand how the 'feet' of music fans could trigger such a reaction in the stadium, although there is an argument that low level frequencies from the PA system might. I would love to hear from a structural engineer as well because I suspect this is far from the truth...or maybe we should write to Myth Busters? Link to comment Share on other sites More sharing options...
shen Posted 16 August 2006 Share Posted 16 August 2006 It's easy really at no time is there ever a standard beat in a footy match!! Even an easy clapping tune goes horribly wrong (some fans have no rythm!!). But at a concert you'll get thousands jumping 'in-time' with a beat. It's like a bridge, they can carry hundreds of tonnes of cars and lorries, but an army, of say 200 men, marching MUST break step because the rhytmical foot-falling might hit the 'resonant frequency' of the bridge and cause either massive swaing or a colapse!! Isn't it mostly theoretical though? I seem to remember a Myth Busters episode where they disproved that this could/would indeed happen... Link to comment Share on other sites More sharing options...
Shum Posted 16 August 2006 Share Posted 16 August 2006 Perhaps, but a combination of winning football and sensible ticket pricing also helped. There's no reason why we couldn't fill the ground again, if the conditions were right. We need to look at introducing those fans fixtures again. £10 adults, and £4/5 for kids, whether you are member or not! Get the fans in. A crowd of 18/19k is pretty piss poor in a 32k stadium. Link to comment Share on other sites More sharing options...
MONreborn Posted 16 August 2006 Share Posted 16 August 2006 We need to look at introducing those fans fixtures again. £10 adults, and £4/5 for kids, whether you are member or not! Get the fans in. A crowd of 18/19k is pretty piss poor in a 32k stadium. In 02/03 we had fans fixtures with prices of 5 quid for adults and 1 quid for kids. Just two or three of these games, well publicised in the Mercury, will give a crowd of 32k IMO So if there are 2 adults to each child, with 14 k season ticket holders the gate receipt for each game would be : 18 divided by 3 = 6 2 times 6 = 12 k adults 1 times 6 = 6 k kids 12,000 times 5 = 60,000 6,000 times 1 = £6,000 TOTAL RECEPITS = £66,000 In comparison to 4,000 supporters, with around 1,000 kids with an attendance of 18,000: kids prices on avearge =£5 ( 1,000*5= 5,000) adults prices on aeverage = ( 20 *3,000 = 60,000) TOTAL RECEIPTS = £65,000 So can we not afford to risk not having the full stadium on discounted prices just for two or three matches a season against the likes of colcchester, no disrespect. We will probably end up on the same income. And by the way, only 60k on matchday tickets as an income is also appalling IMO> Link to comment Share on other sites More sharing options...
Phube Posted 16 August 2006 Share Posted 16 August 2006 Isn't it mostly theoretical though? I seem to remember a Myth Busters episode where they disproved that this could/would indeed happen... You only have to look at the Millenium Bridge in London!! Under normal circumstances it was fine, but if a few people got in a rhythm the minute movement caused people to step in time (like walking in time to music) this caused a huge amount of sway - which although safe was not the best publicity!! In answer to the question above, and no I'm not a structual engineer but have got a physics degree, if 32,000 people do all jump in time with music it will set up a vibration through the stadium infrastructure (you only have to see what happens to fixed stadium cameras at ground when a team score to see the vibrations) and even if these vibrations aren't at THE 'resonant frequency' they can be at whole integer of frequencies (i.e. 2x, 3x etc.) different to cause a potential de-stablising wobble. Imagine i cracks appeared during a huge concert, the press would have a field day!! Not good publicity... If anyone is a structual engineer then please feel free to correct me, but this is what I believe would happen i can stand to be corrected if I'm wrong!! Link to comment Share on other sites More sharing options...
Knighton Matt Posted 16 August 2006 Share Posted 16 August 2006 You only have to look at the Millenium Bridge in London!! Under normal circumstances it was fine, but if a few people got in a rhythm the minute movement caused people to step in time (like walking in time to music) this caused a huge amount of sway - which although safe was not the best publicity!! In answer to the question above, and no I'm not a structual engineer but have got a physics degree, if 32,000 people do all jump in time with music it will set up a vibration through the stadium infrastructure (you only have to see what happens to fixed stadium cameras at ground when a team score to see the vibrations) and even if these vibrations aren't at THE 'resonant frequency' they can be at whole integer of frequencies (i.e. 2x, 3x etc.) different to cause a potential de-stablising wobble. Imagine i cracks appeared during a huge concert, the press would have a field day!! Not good publicity... If anyone is a structual engineer then please feel free to correct me, but this is what I believe would happen i can stand to be corrected if I'm wrong!! Link to comment Share on other sites More sharing options...
Alexikokopops Posted 16 August 2006 Share Posted 16 August 2006 I'm guessing he is refering to resonance - "when one object vibrating at the same natural frequency of a second object forces that second object into vibrational motion." The common example used is the Tacoma Narrows bridge disaster. I'm at a loss to understand how the 'feet' of music fans could trigger such a reaction in the stadium, although there is an argument that low level frequencies from the PA system might. I would love to hear from a structural engineer as well because I suspect this is far from the truth...or maybe we should write to Myth Busters? I did a project on that in Physics A-Level. Fact. Link to comment Share on other sites More sharing options...
Phube Posted 16 August 2006 Share Posted 16 August 2006 Imagine a standard sinusoidal wave. Well you can fit 2 waves of the same amplitude into the same space it would have 2 x the frequency. Therefore even if a low frequency vibration is fatal, then a higher frequency vibration which fits into the low frequency could be bad... Bare in mind I haven't done Physics for 6 years... so I could be rusty, but as I said thi is my understanding of resonant frequencies!! Link to comment Share on other sites More sharing options...
Foxes_Trust Posted 16 August 2006 Author Share Posted 16 August 2006 We need to look at introducing those fans fixtures again. £10 adults, and £4/5 for kids, whether you are member or not! Get the fans in. A crowd of 18/19k is pretty piss poor in a 32k stadium. U12's are £5 now anyway? U8's free So presume you mean the 12-16 age bracket? Link to comment Share on other sites More sharing options...
nhfox Posted 16 August 2006 Share Posted 16 August 2006 I'm guessing he is refering to resonance - "when one object vibrating at the same natural frequency of a second object forces that second object into vibrational motion." The common example used is the Tacoma Narrows bridge disaster. I'm at a loss to understand how the 'feet' of music fans could trigger such a reaction in the stadium, although there is an argument that low level frequencies from the PA system might. I would love to hear from a structural engineer as well because I suspect this is far from the truth...or maybe we should write to Myth Busters? If I were a structural engineer (I'm actually an engineer, but not a structural one), my concern would be when a band is playing a catchy song with a fairly consistent beat -- because fans may start jumping up and down rythmically. It is possible that if a song has a beat which matches the natural frequency, then the stadium could react accordingly. In this case, I don't think the stadium would start cracking straight away -- concrete has elastic properties to it, so it may start swaying first, similar to the Narrows Bridge. I was actually born in Tacoma, so you can imagine the pride I have in the old Tacoma Narrows Bridge. Link to comment Share on other sites More sharing options...
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