How Pedestrians Can Bust a Bridge

[Dibbons]

Interesting science video:

 

[Photon440]

The ancient Romans knew this, their soldiers would stop marching and go into random step when crossing bridges.

 

[cr8crshr]

It creates a Resonant Frequency of the bridge which causes the bridge to vibrate harmonically. Think of the Tacoma Narrows Bridge when it began swaying harmonically because the winds through the Narrows cased the bridge to sway and vibrate until it collapsed. It was also a result of faulty construct but the main cause was the Resonant Frequency...cr8crshr/Bill

 

[Cojohnso1]

It creates a Resonant Frequency of the bridge which causes the bridge to vibrate harmonically. Think of the Tacoma Narrows Bridge when it began swaying harmonically because the winds through the Narrows cased the bridge to sway and vibrate until it collapsed. It was also a result of faulty construct but the main cause was the Resonant Frequency...cr8crshr/Bill

Same reason why a car needs a balancer. Resonant frequency amplitude will increase. Until something bad.

 

[toolmanmike]

Interesting stuff. Thanks for posting.

 

[Budnicks]

I saw something on that stuff in college too
harmonics can cause failures too, certain vibrations
synced up

crazy stuff, can take down even structural steel
or iron structures

there was an episode of Mythbusters they tried to do it
couldn't duplicate it, on the old Caruinez Straights bridge
between Crocket & Vallejo (shithole)

 

[HEMIGTX70]

Yup, you never see a squad, platoon, company, what ever group of people march across a bridge. They all break stride. My grandfather told me one time that he was on a covered bridge and a Beagle was coming across it at more than a walk, kind of like a trot I guess and he said that bridge started to move to the rhythm of that dog's trot. I was shocked, but started to think about it. It made sense.