How do corrugations form?

They're just very, very, very small sand dunes! I don't believe they're started by vehicles although they do exacerbate the problem. I've driven tracks that haven't seen a vehicle for 6 months & they've got corros. I think wind & rain are influencing factors.

Another effect to cause corrugations is the grader operators grading at too high a gear and this causes the blade to bounce as it cuts the surface so causing resultant corrugation.

We call them rumble strips,we put them there to wake you up/stop you falling asleep:p:p:p:p:p.
They are even copying us by putting audible edge strips on highways.
Andrew

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Originally Posted by Jojo

To quote Tom Sheppard (the offroad and overland "guru"):
Corrugations "...are formed by the action (and harmonics) of the suspension and tyres of the track's major-user vehicles on the soil."

Usually, the heavier the vehicle, the more pronounced the corrugations will be. Hence, most corrugations will be formed by heavy vehicles (i.e. heavier than the average 4x4 truck) and thus being a result of their suspension physics. As their harmonics don't match with the ones of our vehicles, we encounter corrugations as shaking, to express it carefully. By adopting a "compatible" speed at which this effect will be minimised corrugations can be driven, but the unsprung parts of the suspension are put on high strain.

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Sorry but your ''guru'' is wrong.I travelled the Tallawana in Jan this year and it had no tyre tracks on it,it could not have had any heavy vehicles on it,I did more than a few three point turns and the Georgia Bore log had no entries for 12 months previous and the track was heavily overgrown so vehicles of any type could not have caused it,also you might try driving some of the inland tracks as most have corrigations in one spot but not another,depending on the wind direction :). Pat

All this time i thought the simple answer was that they were caused by Toiloters & Nissbums.
never felt them in my D2a
Better theory i think.:D

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Originally Posted by PAT303

Sorry but your ''guru'' is wrong.I travelled the Tallawana in Jan this year and it had no tyre tracks on it,it could not have had any heavy vehicles on it,I did more than a few three point turns and the Georgia Bore log had no entries for 12 months previous and the track was heavily overgrown so vehicles of any type could not have caused it,also you might try driving some of the inland tracks as most have corrigations in one spot but not another,depending on the wind direction :). Pat

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That is very true about the Talawana Pat. I did it in October...didn't fill in the visitors book at Georgia Bore. Not much traffic after Cotton Creek turnoff that I could see.:D

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Originally Posted by austastar

Hi,
Yes, I would put a 'weak link' in the line some where.

cheers

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He's referring to an accident where somebody did that and it broke. I remember vaguely that it was on a station and someone was killed.

When I lived in Winton as a young fellow, old council workers reckoned corrugations were caused by independent suspension. Their theory was that corrugations were not noticed back in the 20's-40's before any vehicles had other than beam axles. They reckon you could stand and watch as IFS cars drove past and see the wheels hammering up and down and thus forming corrugations. This argument falls down when it is recalled that in those times there were no made roads in the district, only formed roads that were usually so chopped up by use when wet that corrugations did not exist, only "roads" that looked like ploughed fields.

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Originally Posted by Quigley

I've often thought about corrugations when driving on them, and wondered how and why they form.
There must be an explanation.
The more you think about it, the harder it is to get to a theory that explains it.
Any answers?

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It starts with a hole in a dirt track and a vehicle with poor damping...

Vehicle hits the hole and the subsequent oscillations in the suspension start forming the corrugations. These corrugations then induce further oscillations, in subsequent vehicles, making them go on further & further.

M

http://www.tobsen77.de/images/shop/vezdekhod_thumb.jpg

The anti 4wd mob have a fleet of these that are rostered on permanent nightshift across the country.

I think pedestrians crossing the road cause the corrugations and the council maintain them. I was told by an old bloke that grading is pointless without a proper deep ripping first as the corrugations go a lot deeper than what you see and the usual quick skim with the blade over the top is next to useless.