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M62 Street Lights In High Wind - OUCH!

Chrishazle

MB Enthusiast
Joined
Nov 13, 2008
Messages
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Location
Nr Ashford, Kent
Car
2008 S204 C220CDI Elegance Estate Auto, 2008 R171 facelift SLK280 Auto.
Wow. Not good position to be in……wonder if the wind is just the right resonance to affect the lamp posts because the vehicles don't seem affected much?
 
Dunno - I'll be seeing him at the pub tomorrow evening so may get more info. I think these are the new style tall LED columns currently popular with highways because they're cheap to install and run!
 
The one next to the gantry seems to be totally unaffected...
 
Some years ago, a number of the central reservation lights blew over on the moorland section of the M62.

Frightening !!
 
Wow. Not good position to be in……wonder if the wind is just the right resonance to affect the lamp posts because the vehicles don't seem affected much?

Yes. Looks like its just hit the right frequency for them to react like that.

They do look flexible.
 
I'm told Kent is planning to replace all the current orange street lighting with these LED columns - another way of causing chaos on the M2 and M20!
 
I came over the M62 last night on the way back from the Southport curry night. Wind and snow was horrendous light poles waving but not as bad as the video. Only one track through the snow over saddle worth the Volvo with winter tyre romped up it I passed several MB and BMW plus others that could not get up the track meaning I had to go into the deep snow in the outside lane to pass them. A volvo and winter tyres is a hard combination to beat when it gets rough going
 
A volvo and winter tyres is a hard combination to beat when it gets rough going

I can vouch for that - Volvo cars are clearly designed with snowy winter conditions in mind.
 
I once visited a factory making tubular lighting poles. The feedstock was the bottom of the barrel - normal tube that wasn't saleable for anything higher integrity like squirting liquids or gas up the middle. Bish, bosh, weld, weld, quick hot dip galvanise and job's a gud 'un. Stick that in the ground for 20 years.

I hope whoever designed and installed these monsters did all the fatigue life calculations as if they were aircraft wings, otherwise sooner or later there's the risk one will snap near the base.

.
 
Well, apparently this phenomena is down to "Vortex Shredding"

A guy on another forum said the following: -

This is indeed vortex shedding and a pretty cool demonstration of it in action. In a nutshell, as the air flows around the lamp post the flow separates alternately from each side. Each time a vortex is shed the load on the post changes, and due to the design of the post, the elastic properties of the material, the weight of the light etc, there will be a certain frequency at which the oscillatory shedding of the vortices will match the resonant frequency of the lamp post and this can become destructive as the forces involved can be quite large. This is why chimneys often have those spiral runners around the top, these are designed to shed the vortices in a predictable manner, instead of the oscillating vortices shed by a pure cylinder and so stop the chimney from shaking itself apart. Similar to the bridge at Takoma Narrows bridge, when the wind caused it to break apart or when the Millenium Bridge first opened and the movement of people caused it to sway.
The cool thing about vortex shedding is that any cylinder will shed vortices in this way, from a very thin wire that 'sings in the wind' where the shedding frequency is so high it produces an audible pressure wave through to huge vortices that form around entire islands. You can predict the frequency of the vortex shedding if you know the speed of the flow around the object and it's size using the Strouhal Number which is more or less constant for an object like a cylinder.
Wrote a paper about using this phenomenon to scale data generated during CFD simulations last year and this kind of topic is right up my street. Knew one day my PhD would come in handy.

Another expanation from the same forum by another poster was: -

That lorry up ahead is from the magnet factory.

Which is an explanation I much prefer. :D
 
Are the new poles not made of composite? I remember reading a while ago that signposts, lamp standards & road furniture poles were being transitioned to composite as they fail more gracefully in the event of a crash

If you hit a steel pole in a car or motorbike it's liable to write the car, or you, off

Nick Froome
 
Are the new poles not made of composite? I remember reading a while ago that signposts, lamp standards & road furniture poles were being transitioned to composite as they fail more gracefully in the event of a crash

If you hit a steel pole in a car or motorbike it's liable to write the car, or you, off

Nick Froome

I think some are now designed to fail at the bottom in the event of a collision , reducing damage and/or injury .
 
I can vouch for that - Volvo cars are clearly designed with snowy winter conditions in mind.

Thought it was just me!

Left the E Class and ML at home and went to work in the V olvo.
 
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The one next to the gantry seems to be totally unaffected...

Maybe because of it's location it's designed not to move so it doesn't connect with said gantry.
 
I used to go over the M62 Moorland Stretch (and other parts) in my LWB Sprinter. Not for the faint hearted, especially if the van was empty. True Mary Poppins moments which were also in evidence crossing Barton Bridge and the Thelwall Viaduct. EEK!
 
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