Behold, the power of Tae Bo.

[Minvaren]

Link

Seventeen people performing a vigorous Tae Bo workout caused tremors that forced the evacuation of a South Korean skyscraper earlier this month, the building's owners say.

Prime Group, owner of the 39-story TechnoMart commercial-residential high-rise in Seoul, said 17 middle-aged people were working out to the pop song "The Power" by Snap on July 5 when their movements set the upper floors of the tower shaking for 10 minutes, according to a report from the Korea JoongAng Daily.

Bit surprised that it wasn't "Humpty Dance," but hey, whatever works...   

[Hawkbit]

Last words:  "Aaahhh this skyscraper is going to collapse.  It's gettin'... it's gettin'... it's gettin' kinda hectic."

It wasn't the Tae Bo, it was The Power. 

[Strazos]

I don't buy that story - who still does Tae Bo? 

[Chimpy]

Bit surprised that it wasn't "Humpty Dance," but hey, whatever works...  

The Humpty Dance wouldn't work because no two people will do it the same.

[Sky]

Wouldn't a harmonic resonance from the music be more likely?

[Cyrrex]

Bit surprised that it wasn't "Humpty Dance," but hey, whatever works...  

The Humpty Dance wouldn't work because no two people will do it the same.

Well played, that had me rolling 

[Murgos]

Wouldn't a harmonic resonance from the music be more likely?

Than a harmonic resonance from people moving in unison?  Not necessarily.

[Morat20]

Back to my favorite physics anecdote that I've never had officially verified -- Roman legionaires used to break step when crossing bridges, to avoid that exact problem. :)

[Murgos]

Back to my favorite physics anecdote that I've never had officially verified -- Roman legionaires used to break step when crossing bridges, to avoid that exact problem. :)

Break Step March is still a command in modern day drill.

[Merusk]

Mythbusters tried to disprove that one, but I have great issues with their contraption and methods used on that particular myth.

Tesla did HR tests, didn't he?  I seem to recall that.  This building, though, I'm just going to go with shitty construction. 

[Morat20]

Mythbusters tried to disprove that one, but I have great issues with their contraption and methods used on that particular myth.

Tesla did HR tests, didn't he?  I seem to recall that.  This building, though, I'm just going to go with shitty construction. 

It's difficult to disprove. It's certainly physically possible -- resonance effects in bridges are well known (that Narrows bridge that collapsed under wind gusts is a famous example) -- the difficulty is since not all bridges are the same, and will thus be more susceptable to different resonances.

So Romans marching across a bridge can collapse it if they're walking in perfect time. If the bridge is the proper size and construction. The odds of any given bridge collapsing are probably low, but without enough legions crossing enough bridges, some are going to fall.

[Chimpy]

Well played, that had me rolling 

Did I ruin the image and the style you're used to?

 

[NowhereMan]

The London Millenium Bridge suffered from harmonic resonance simply from enough people happening to walk in step, which caused the bridge to wobble enough to cause more people to fall into the same step, which made  the problem worse. Until they closed the bridge and fixed it.

I also know Albert bridge up near Battersea Park has (or had, they're renovating it) a sign telling troops crossing it to break step.

[Fordel]

Back to my favorite physics anecdote that I've never had officially verified -- Roman legionaires used to break step when crossing bridges, to avoid that exact problem. :)

Break Step March is still a command in modern day drill.

Yea, I remember as a little boy my father explaining that to me, when he was in the army, you would do that on bridges just for that reason. He used to also do that to tease me, since as a wee lad I would try to match his footsteps