Uses same technology like a grid from a heating blanket...or a rear-window defogger...with a bit more wattage. Buried rebar or other similar conducting medium just under the bridge's road surface would be charged with electricity to keep the surface of the overpass above 32 degrees Fahrenheit during freezing weather. Could be powered by a small solar panel or wind-driven turbine located close by. Much more enviromentally friendly than salt or cinders.-- muzer, Oct 02 2003 Same except it's gas lines and flames http://www.halfbake...a/Burning_20Bridges [FarmerJohn, Oct 21 2004] Baked http://www.smartbri...dge/HBTprojects.htmNot Widely, maybe, but they're certainly out there. [DrCurry, Oct 21 2004] Virginia's heated bridge http://www.virginia...e/faq-hotbridge.aspAnother heated bridge, in Virginia [themanfire, Oct 21 2004] Now, with added geothermal-ness http://www.smartbridge.okstate.edu/ [mouseposture, Jun 13 2010] For [goldbb] Not recommended http://www.youtube....watch?v=WEQrt_w7gN4 [mouseposture, Jun 13 2010] I got no problem with salt or cinders-- dickity, Oct 02 2003 also,get a truck if driving over ice is hard for your 1978 Volkswagan-- dickity, Oct 02 2003 Then all the roads will have to have signs every hundred feet saying “Road Ices Before Bridge”.-- pluterday, Oct 02 2003 It's so cold out, you could fry an egg on the freeway.-- Amos Kito, Oct 02 2003 Saw once reference to heat sink under permafrost buildings, to keep from sinking into the earth. What of melt road ice same way, or keep sidewalks clear? Just in reverse -and warm air RISES - must be easier. D.-- dinosnider, Oct 02 2003 The intention is good, but I feel doubtful that enough power would be generated by "a small solar panel or wind-driven turbine." Maybe one of our number-crunchers can supply a guesstimate.-- FarmerJohn, Oct 02 2003 Modern runways are heated!-- grahamhgreen, Oct 03 2003 Welcome to HB, [muzer].
I feel doubtful that a small solar panel will yield power while it is snowing. Is there any way to make a car-heated bridge, using magnetic induction?-- Laughs Last, Oct 03 2003 I know some frat guys who would be willing to stand on the side of the road and melt away the ice with umm, beer induced excretions. And don't worry, they assured me that they'd throw in window defrosting at no extra charge.-- VuDuBlade, Oct 05 2003 Heating bridges would work, but would use a lot of energy. As an alternative, how about cooling the bridge? Traction is lowest when ice is near 32F because it can form a thin layer of water on top. If the ice were cooler, then it wouldn't have the water layer.
To be sure, you wouldn't want to be trying to freeze the bridge when the air temperature is in the 40's or when it's raining, but if the temperature is well-below freezing, cooling the bridge may be easier than heating it.-- supercat, Oct 05 2003 This is already baked in some places in Iceland (using waste Geothermal heat rather than solar or wind power).-- Gordon Comstock, Oct 06 2003 Bridges ice up faster than roads.-- waugsqueke, Oct 06 2003 The Smart Road project near my alma mater Virginia Tech -- which has its own snowmaking machines for testing out various ways of handling icy conditions -- has been looking into heated roadways as a possibility. Here are some URLs:
http://www.ctr.vt.edu/ http://www.techtv.com/news/scitech/story/0,24195,3372585,00.html http://www.virginiadot.org/projects/constsal-smartrdoverview.asp http://www.virginiadot.org/infoservice/technology.asp-- themanfire, Oct 06 2003 This was a very astute idea!:
Is there any way to make a car-heated bridge, using magnetic induction?
Laughs Last, Oct 03 2003
Passing cars would charge up (a) battery or capacitor to keep things warmed up when the sun is obscured. The local bridges here in Sweden are heated by the central heating works, piping hot water to the entire town of 100,000 or so. 'Course, I pay for it, too.-- stringstretcher, Oct 30 2003 I recall mention of a system they were considering implementing here in Ohio that involves sprayer heads recessed at intervals in the bridge's road surface that intermittently spray a de-icing liquid.-- kmrowe6647, Oct 30 2003 Well, I'm sure it's baked somewhere heated sidewalks are all over the place. Probably a good idea, although it take way more power than a small wind turbine or solar panel. Heating with elictricity takes a lot of juice. But if it's just on bridges and only when conditions are right for forming ice on the surface total consuption might not be too high-- tedhaubrich, Jun 02 2004 Taking the brute-force method of simply piling gas/electrical energy into the problem is very american. Perhaps a more elegant solution is to pump water through the road way in a loop that goes DEEP into the foundations (you could design this in when laying the foundations). Below 4/5 metres underground the temperature is around 12 celcius, which is more than enough to melt the ice. A wind turbine would be much more likely to come up with the goods in terms of pumping energy rather than straight heating.-- bs0u0155, Jun 13 2010 [bs0u0155] Excellent idea, and now also baked <link>-- mouseposture, Jun 13 2010 Instead of heating/cooling the bridge, how about vibrating it to break off any accumulated ice?-- goldbb, Jun 13 2010 [goldbb] Also baked, in a manner of speaking <link>-- mouseposture, Jun 13 2010 What's so special about a bridge for heated cars? Are we currently expected to turn on the A/C before we cross bridges?-- swimswim, Jun 14 2010 random, halfbakery