In Volgograd a few years ago...

"Grindintosecond" (Grindintosecond) 09/14/2019 at 10:29 • Filed to: None

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I remember, as a kid, seeing footage of the 1940 Tacoma Narrows bridge disaster. And since a bridge across the river in my childhood town had suspension elements,

I was always wondering if it would do the same thing. But in forty years since the Tacoma event, engineers have learned quite a bit.   Since then bridge vs. wind harmonics are studied fiercely if anyone wants to design a bridge. Wind tunnel time, even, as we see in the end of the second video.

. But here we see a new steel construction with concrete pylons. Perhaps they need to construct additional pylons..... pylons...

SBA Thanks You For All The Fish > Grindintosecond 09/14/2019 at 10:51

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Whoa.  I’d love to understand the physics of that.  How does it do that with so many pilings to support the bridge deck?  That’s wild.

gmporschenut also a fan of hondas > SBA Thanks You For All The Fish 09/14/2019 at 15:13

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SBA Thanks You For All The Fish > gmporschenut also a fan of hondas 09/14/2019 at 15:17

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Thanks for the standing node GIF. Yeah, it’s weird. You’d expect the frequency to be a lot higher, but it looks like the side structure is actually making the problem worse— and there must be a lot of mass moving in the vertical axis.

Somebody’s FEM c omputer model screwed the pooch...

gmporschenut also a fan of hondas > SBA Thanks You For All The Fish 09/14/2019 at 17:11

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or they never expected it could get oscillating to that much of a wavelength. In any case, very weird.