London Millenium Bridge Opening

"Nice" lateral vibrations like on Tacoma Bridge

[@jasstan180]

Came here to see what my physics teacher was talking about

[@arcl8518]

me too

[@arleneagunias-daantos5521]

lmao for me it's my dt teacher

[@zayasi4410]

Came here to do my homework :(

[@orangestudio1711]

Damn our teacher must have came from the same place

[@scenzonhain3815]

Same lol

[@harmonicresonanceproject]

I was there that week when it opened - it was not so busy when we went so not swaying too badly, but everyone was talking about it. Happy days though, back in 2000.

[@carschmn]

The people on the wobbly bridge look like they are having a dance party.

[@vipulprakash1987]

The design, the diagnosis of the pedestrian induced vibration problem and the remedy are all defective. 1. The Design is defective as an unstable transverse configuration was chosen. If you consider the transverse X-section of the bridge deck, you will find that the gravity load on the footpath and the two equilibriating reactions from the inclined ties between the deck and suspension ropes are collinear, and the three meet at a point below the deck. In the very first course of structural analysis, usually called Engineering Mechanics or Statics, we are taught that a 2D structure, such as a Beam, supported by 3 reactions will be unstable if the 3 reactions are either parallel or collinear. In this case there are two reactions along the line joining the deck with the suspension cables on either side and the gravity load vector passing vertically through the deck center. The three force vectors are collinear through a point below the deck and lying on the vertical through the deck center. About this point the deck can rotate without any resistance. This wobbly motion is what actually happened. 2. The diagnosis of the problem is wrong on even more accounts. Suspension bridges are typically even more flexible with very long periods of vibration. They do not exhibit pedestrian induced vibrations. Truss bridges as well as Beam bridges on the other hand are very stiff with very short periods of vibration. They also do not exhibit pedestrian induced vibrations. For economic reasons the sag of the suspension cables in suspension bridges is kept large, usually Span/10 and only vertical sag is provided. In this case a very shallow inclined sag of span/60 was provided. This not only made the bridge uneconomical but 6 times more stiffer than a usual suspension bridge with a sag of span/10. This increased stiffness reduced the period of vibration by 2.5 times, and made it coincide with the period of pedestrian footfalls. 3. The remedy for the mis-diagnosed problem costed about 25% of its initial cost. It involved installation of a large number of damping devices that would involve frequent maintenance. There are thousands of bridges of all types designed by run-of-the-mill structural engineers that continue to function well. In most of them neither wind-induced nor pedestrian-induced vibrations have been considered in design. In fact most of the existing bridges were designed manually with the help of slide rule or calculators - - the structural analysis computer programs were non-existent. The designers then knew their structures more intimately. The existence of Modern structural analysis and design computer software disengages the designer from analysis and design and is the cause of the problem.

[@chris2145]

TLDNR and i speak for everyone

[@thespacejedi]

@@chris2145 its TLDR

[@SobrietyandSolace]

Ok I have no idea how they fucked this up so catastrophically because as a total layperson who knows nothing about bridges or engineering your comment makes sense to me, so surely someone who studies this shit for a living would have had the foresight.

[@IamChandEvil]

Dubstep bridge with low natural frequency wobbles

[@trinhang7510]

Even though they know the bridge was moving, they kept walking and standing there.

[@MrFindlaya]

Does anyone know where this footage comes from? I want to get access to a higher quality version of it.

[@Platypi007]

You didn't actually pay attention to the video... They discovered that many bridges exhibit this kind of motion when a lot of people walk over them at the same time. It isn't the bridge design--it's a function of people responding the the movement of the bridge amplifying the effect. It's resonance.

[@rensseak]

I think all the people taught to get in sync with bridge just for easyer walk on it. But with that it got more worse.

[@set921]

No. They closed it for 2 years and fixed it. Most bridges don't resonate this severely.

[@jimmydcricket5893]

160 people isn't that many.

[@abbyosborn413]

@@jimmydcricket5893 there was 250+ people on that bridge that day

[@JangoFett220]

Now I understand why Craig Charles referred to this bridge while describing Bridge Ball on Takeshi’s Castle

[@SobrietyandSolace]

Bumped into him at Comicon a few years back

[@shazf18]

This is the same bridge in Harry Potter that the death eaters bring down

[@moneymule8209]

and somehow normal people still have no idea magic exists....

[@Davvg]

read another book

[@carolwhittle833]

RIP Tony. God bless, Carol

[@ThomasGabrielsen]

Stephen Fry @ 2:19

[@Undamen]

London bridges swaying around

[@GOTTshua]

Frequency of our hearts, aligned for good, would be a blessing.

[@jamie9926]

Anyone here from Humble Pi?

[@schwarzerritter5724]

SciShow.

[@peggyperl]

Very interesting!

[@major600]

Fascinating...and kind of funny.

[@IronMan-qi3yg]

RIP Tony

[@imapaine-diaz4451]

They should have realized that any large group of persons walking together tend to very soon match their stride to follow the pace of the group. if they don't, they soon start tripping over each others feet. this produces the same effect as a marching troop of soldiers and for the same reason.

[@bagoh4]

Reminds me of Goomba's from the live action movie swaying side to side.

[@rexster63]

Unfortunately they still dont get it, the on or off wobble is a phase transition, the people walking in synch did it because the wobble made them synch. Read Strogatz book Synch.

[@djbeninatl]

At 3:00, the ppl look like a bunch of penguins.

[@GulshanVerma]

ok

[@MatSallehBoleh]

I love Pat Dallard, master of understatement at 00:44. "It was, erm, very disappointing". Don't you mean "we shat bricks"?

[@johneastmond9092]

Some folks (I'm sure) think that's a dumb question. It's not! The structure has enough mass that the stationary momentum would keep things stable w/ the number of people who would be on the bridge at once on a typical day. The fix is quite elegant! Can you see the change?

[@Gofaqyaselves]

Who knew the G-force generated by thousands of people could warp a big ass bridge like that. Trippy

[@sparlexna]

The "giggidy giggidy" bridge would be a nice name :)

[@andrewstearns1444]

Anyone here from ECE 504?

[@AnwarMuhammad709]

Who there in 2020 November

[@set921]

The marching in unison myth has been disproven.

[@pianojamboree6001]

Differential Equations brought me here :(

[@plutoh28]

same.

[@noahloos2476]

Unterricht 2020

[@HarkyOfficial]

@45pudding haha so am I and my lecturer told us to watch this video!

[@scilabo]

@dnahk2483 not to mention Structural Engineers!

[@mwhiten100]

Alexandria Bridge, Ottawa at 4:50

[@zennynequin1405]

Anybody that has been on a ship knows this...They messed up

[@xman4un]

Does one want a bridge to react that way???

[@theallie7577]

They said people were hanging on to the bridge cuz it was moving so much Disappointed.......

[@IanBPPK]

What questions to ask......

[@TopGearrules]

Why didnt they just keep it like that!

[@JuicerMcGooserr]

Bridge

[@adammineris]

Do a AMA?

[@abdelhamidahajjam2517]

Mines 2016 :')

[@lucasthelisson7372]

Dedicace a damien dupré

[@johneastmond9092]

How do you NOT know about pedestrian lateral loads?! Any video of people walking shows side-to-side motion in they're upper bodies. (That sideways motion requires lateral loading) People on ice demonstrate need for lateral containment. (Feet kick out to side) How many ways can you think of someone accidentally doing the splits? What about the ways you have slid?

[@Seanmcdhuibhne]

Why not call it The Diddy Bridge or The Drunken Bridge

[@jamestoyn9755]

in what year did the bridge open.

[@bullman86]

@merederem not that my mum

[@skyline_drones]

@dnahk2483 more Civil Engineering than Mechanical but ok :)

[@carmusen]

It was the Death Eaters!

[@AccatagliatoIt]

il Millenium Bridge, il ponte pedonale sul Tamigi, inaugurato il 10 giugno 2000 è stato chiuso dopo 2 giorni a causa delle forti oscillazioni laterali dovute alla risonanza indotta dal passaggio dei pedoni. Per limitare le oscillazioni forzate del ponte sono stati inseriti smorzatori che dissipano l'energia trasmessa in modo inconsapevole dai pedoni

[@AccatagliatoIt]

Il Millenium Bridge è un ponte pedonale sul Tamigi nel cuore di Londra. Si tratta di un ponte lungo 325 m, diviso in tre sezioni, la cui caratteristica principale è che le funi di sospensione, anziché essere poste sopra il piano stradale, come accade nella maggior parte dei ponti sospesi, sono poste ai lati, dando a chi lo attraversa un maggiore senso di . Il ponte è stato progettato per sopportare il passaggio, in condizioni di lavoro ordinario, di 5000 persone simultaneamente. Il ponte è stato aperto nel giugno del 2000, e il problema che ha portato alla sua chiusura due giorni dopo si è manifestato proprio nel giorno dell'inaugurazione. Dopo che il ponte si era riempito di pedoni che camminavano nelle due direzioni, si è instaurata una oscillazione laterale che, induceva i passanti a modificare la propria andatura fino a camminare tutti all'unisono. Pur non rivelandosi distruttiva, l'oscillazione spostava il piano del ponte da destra a sinistra per 7 cm, e rendeva necessario ad un numero significativo di persone di reggersi alla balaustra per mantenere l'equilibrio.

[@lourdescolomes8686]

Quién llegó aquí por instagram.com/tercosmicqu...?

[@Foxy.Tea.]

Bruh

[@arleneagunias-daantos5521]

who else is here because their teacher sent them here.

[@gwydion5348]

phteven

[@bekjanomirzak224]

Is there anybody else who is watching this after reading section of IELTS?

[@Pwells1]

Curse you Bellatrix!

[@thegombie]

stupid biased video. Rope bridges have existed for ages, and we all know what happens when you sway on them.

[@hellopellos]

upvote me for le reddit xD!

[@whythelongface4149]

Really shitty waste of money. 'Galloping Gertie' no2.

[@Spudst3r]

What a poorly engineered bridge. You don't want bridges to shake!

[@lihinilemon9597]

It is science If you have learned physics you would understand It happened because the frequency of the force became equal to the natural frequency It is under simple harmonic motion

[@parryhotter8788]

bruh

[@ifandafyddwilliams5270]

phteven