Galloping Gertie in Russia
Galloping Gertie in Russia
(OP)
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...
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






RE: Galloping Gertie in Russia
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
RE: Galloping Gertie in Russia
http://www.youtube.com/watch?v=chaiT3RXXRk
RE: Galloping Gertie in Russia
Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask
RE: Galloping Gertie in Russia
Doug Jenkins
Interactive Design Services
http://newtonexcelbach.wordpress.com/
RE: Galloping Gertie in Russia
Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask
RE: Galloping Gertie in Russia
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<)
RE: Galloping Gertie in Russia
http://imechanica.org/node/8280
RE: Galloping Gertie in Russia
Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask
RE: Galloping Gertie in Russia
An expert is a man who has made all the mistakes which can be made in a very narrow field
RE: Galloping Gertie in Russia
RE: Galloping Gertie in Russia
Just open up the sides of the bridge so the wind can go through without problems !
RE: Galloping Gertie in Russia
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.
RE: Galloping Gertie in Russia
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.