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nonmetallic manhole cover

wont tempt thieves
  (+6, -2)
(+6, -2)
  [vote for,

In 3rd world countries, poor people resort to stealing stuff made out of metal like manhole covers and the like to sell to shady recycling stores who melt down the metal and sell them, probably to china. Of course a hole in the street is an accident waiting to happen.

I suggest using some sort of composite material instead. Maybe fiber reinforced concrete or plastic. Of course, this assumes that it is possible to make it strong enough.

The covers will most probably cost more and wont last as long but it would be worth it to deny those thieves an easy score and to reduce traffic accidents.

Preferably this would be a drop i replacement for existing covers. Also, since a lot of 3rd world streets save money on road maintenance by just adding more layers of asphalt or concrete on top of the road, leaving the manhole entrance in a depression, it would be possible to make a cover that is thicker and stronger than normal.

vmaldia, May 23 2009


       make them from the material that the rest of the road is made from - you won't even see them then.
po, May 23 2009

       [+] A very real problem here in South Africa.
danman, May 23 2009

       About 20 minutes ago I drove past a man-hole cover replacement team (rare even for us). Four guys loading a metal reinforced concrete circle about 40cm thick, looks like about 300 kg, probably just over 100 kg. I would imagine this is a good enough solution, forcing the "effort over intrinsic value" ratio into a large enough number for the criminals to ignore it. Of course this will see an increase in the theft of things more aligned to the criminal's effort v value equation.   

       An extreme example is the coloured glass imparting red or orange or green at traffic lights. In the copper belt regions in northern Zambia the traffic lights are all one colour, the colour of the bulbs. The coloured glass in front of the bulbs has been taken, broken up and sold off as precious gems to unsuspecting speculators. Weird but true... It goes without saying that there are no more man-hole covers there.   

       To really solve the problem of criminal intent and ingenuity one has to address the problem of poverty, and need (or greed). This can never be done completely (as witnessed in the British Houses of Parliment).   

       Anyhow, a worthless man-hole cover is a good idea. But it is a bit of a WIWCH (what if we could have...)
4whom, May 23 2009

       //Of course, this assumes that it is possible to make it strong enough// easily achieved and most sensible, but is there not some mad voodoo symbol that could be printed unto the metal ones, accompanied by a serious curse that is triggered on the removal of the covers, then activated, released and visited on all those engaged in any subsequent melting process?   

       Well that would be my solution. I'm calling it Voodoo Draindoos.
xenzag, May 23 2009

       What we need at the bakery is a manhole-cover harvester, which lifts covers as it drives over them, using electromagnets.
ldischler, May 23 2009

       There was a problem like this in Mexico 30 years ago, and this solution was implemented: The metal rim and cover where replaced by concrete ones. A metal reinforced rich in concrete disk is a stapple here, for -say- pluvial sewer. The weight is just the same, and the disk has holes in order to use the same tool used to open metal covers.   

       For the case of manhole covers that need to be metal, a metal door with a thick hinge and a trick lock is used.
noyola, May 23 2009

       We could make the man-holes out of extremely dense metals, such as gold or plutonium. That should keep those thieves from taking them, 'cause they'd be too heavy.
MikeD, May 23 2009

       [MikeD] I think you may find that the effort v value proposition would then swing in favour of the criminals, for gold, paladium, platinum, lead, etc. Besides none of these exhibit a strength in compression or torsion anything close to iron, or re-inforced concrete.
4whom, May 23 2009

       I think MikeD is on to something, there. If Diamonds are cast in as well, they would not only show everyone where the manhole cover was at night, but would thwart any attempt to melt the material down and refine it.
Ling, May 23 2009

       Yes, [Ling], the diamonds are an excellent idea, but shouldn't we put rubies on the 'Wrong Way" side, to alert drivers in the same manner that the road reflectors do? Safety is what is most important, and we must not lose sight of this.
MikeD, May 23 2009

       Now if we could only cast or cut big stones.
wjt, May 23 2009

       Rather widespread, as [21_Quest] mentioned
loonquawl, May 25 2009

       Weapons grade plutonium is pretty heavy
Bad Jim, May 25 2009

       Depleted uranium? Osmium? Tiny Neutron stars?   

       Perhaps if the LHC ever gets going again they could produce contained black holes, those would be pretty heavy. Oh no! They would have to be contained in a vacuum, and as such, would fly off directly into space :-).
4whom, May 25 2009

       Some of the larger cities in the US actually weld the covers shut before major holidays and events to keep pranksters from making things dangrous. I don't know the extent of the theft problem but I imagine that welding a cover shut minimizes this problem.
Jscotty, May 25 2009

       What [po] said. [+]
AbsintheWithoutLeave, May 25 2009

       I'm glad they don't weld them shut here. The reservoir would be the only way out then.   

       light/strong ... not steal-able. These two ideas actually preclude each other (no offense intended). My suggestion? Stirpiculture...   

       Yes, it's Eugenics I'm suggestin'. But Wake-up people! (Treat the malady, not the symptoms...)
Speed Razor, May 26 2009

       Would it be cost effective to carve manhole covers out of granite or marble?
Jscotty, May 26 2009


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