Galloping Gertie in Russia 1

[msquared48]

Interesting video in the news tonight showing the same torsional oscillation in the bridge deck as we have all seen in Galloping Gertie, only this one is due to high river flows. Possibly was the Volga River in Russia - at Volgagrade.

The bridge is only a year old. One comment was that a support had "failed". Looks like harmonic response due to vortex shedding off the piers from the high sustained flow. Possibly some base scouring has occured, allowing the pier(s) to twist inducing the response.

Brings back memories...

Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask

 

[msquared48]

Oh...

This is not a suspension bridge as was Galloping Gertie, but more like a causeway.

Chubby Checker would be proud.

Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask

 

[asixth]

Is this it mike

http://www.youtube.com/watch?v=chaiT3RXXRk

 

[msquared48]

Yep. That's it.

Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask

 

[IDS]

Where does it say that it was due to high river flows? Reports I have read say high winds, and that is what it looks like.

Doug Jenkins
Interactive Design Services

http://newtonexcelbach.wordpress.com/

 

[msquared48]

The report on local TV last night said high river flows. The area is currently seeing flooding.

Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask

 

[racookpe1978]

Seems like flooding (scouring of the piers) or even sideways forces (twisting or rolling of the piers) would produce a side-to-side motion.

The piers all appear uniform from the side view, and, from the deck view, are not moving noticeably sideways or twisting.

But the up and down motion of the deck is much, much greater than of the piers directly below them. Which doesn't say a blasted thing about why the deck is moving, only is a symptom that the deck is moving vigorously up and down while piers appear steady. 8<)

 

[TERIO]

Another link to a longer youtube video is posted here:

http://imechanica.org/node/8280

 

[msquared48]

Now a web article is blaming the wind...

Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask

 

[rowingengineer]

If I understand correctly, the wind at the time of the incident was about 14 m/sec (31MPH). your guess is probably better than mine.

An expert is a man who has made all the mistakes which can be made in a very narrow field

 

[apsix]

I convinced myself that it was a fake........

 

[Robertmet]

Tacoma's lessons have been lost on the Russians !
Just open up the sides of the bridge so the wind can go through without problems !

 

[EngineerTex]

But the up and down motion of the deck is much, much greater than of the piers directly below them. Which doesn't say a blasted thing about why the deck is moving, only is a symptom that the deck is moving vigorously up and down while piers appear steady.

I think you may be onto something. Are you thinking it could be that the piers are providing a harmonic excitation (even out of plane) of a very tiny amount, ending up with serious resulting amplitudes in the deck?

Engineering is not the science behind building. It is the science behind not building.

 

[kelowna]

I think you are overcomplicating it.

The armonic excitation has an amplitude of twice the span length. The pier locations are the points in which there is no movement (logic otherwise). While a span goes up, the adjacent ones are going down, not moving at pier locations.

The piers are not doing anything here, the wind is. I guess tjat particular wind speed is causing inestability at precisely that armonic amplitude.

To resolve the issue is relatively simple once you know what caused it. changing the parapet configuration (maybe making it solid or higher) or putting a plate at the bottom of the section will change the bridge response and remove the bridge response from that armonic amplitude. Dampers are another option, to amortiguate the response and avoid amplification, but they would not be so effective.