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>though surely this has been dealt with before, as there's a lot of places where they cover parking lots with elevated solar panels like this. As a side note,

by jaclaz 9y ago

>though surely this has been dealt with before, as there's a lot of places where they cover parking lots with elevated solar panels like this. As a side note, you have to consider how in parking lots it is rare to have cars and trucks passing under the panels at 70 Mph, and more generally accidents are usually very low speed. Besides the "normal" resistance to wind, if you want to build a sort of half-pipe covering a highway you need to consider the pressure induced from the inside by high-speed moving objects and the possibility to resist accidents (preventing an 18 wheeler from completely crash a - say - 100 m section of the half-pipe in case of an accident needs a rather sturdy structure). So, more or less it would be needed to build an artificial tunnel (concrete, rather thick) similar to a "snow shed": https://en.wikipedia.org/wiki/Snow_shed https://en.wikipedia.org/wiki/Snow_shed http://wsdotblog.blogspot.it/2014/03/the-i-90-snowshed-retires-after-64-years.html http://wsdotblog.blogspot.it/2014/03/the-i-90-snowshed-retir... The "lighter" metal/lattice ones are only used usually for railways.

SomeCollegeBro 9y ago
> Besides the "normal" resistance to wind, if you want to build a sort of half-pipe covering a highway you need to consider the pressure induced from the inside by high-speed moving objects and the possibility to resist accidents (preventing an 18 wheeler from completely crash a - say - 100 m section of the half-pipe in case of an accident needs a rather sturdy structure). I mean, aren't these issues already basically solved? I frequently drive through miles-long tunnels under Boston at 70mph.
- rtkwe 9y ago
  A tunnel is already massively over specced for that because it's preventing the tons of soil/rock/building overhead from collapsing down. The forces for cars passing underneath is minuscule compared to that. For a hypothetical covered roadway you want something much cheaper and lighter so it's not mind numbingly expensive to build.
gorkonsine 9y ago
That's true, I didn't fully elaborate on all that but yeah, there's concerns there that wouldn't exist for a parking lot. However, you bring up a great point with the "snow shed": covering all or part of a road with solar panels like this would also have the side effect of keeping bad weather off the road. How much money would that save in show-shoveling costs, and the costs to society of having roads blocked by snow (and snowplows), and having weather-induced accidents (both rain and snow)? Now, it's probably not feasible to cover every little road in a city with these things, but at least covering major arteries, while probably somewhat expensive due to the engineering challenges you raise, would have some major benefits: keeping the main roads clear even during horrible weather, and also providing a lot of energy from the solar panels.
- jaclaz 9y ago
  You have an excellent point there, but the costs are unfortunately way too high to be feasible, not even remotely. And you have to consider how - in places where there is snow - you have to choose to either forfeit the (possibly little) energy the panels can produce in winter or anyway clean them from the snow anyway. The good ol' rule of the thumb is that (of course it depends on the country) the cost is 10,000,000 Euro's per km of highway (plain, mainly earthworks), 20,000,000 per km on bridges/viaducts, 30,000,000 per km in tunnels. (the "base" price may of course vary, but the relative proportions remain roughly valid) An artifical tunnel or sbow shed, besides the solar panels, would be probably 1.5 to 1.7 times the cost of the "simple" highway.

by jaclaz 9y ago

SomeCollegeBro 9y ago

> Besides the "normal" resistance to wind, if you want to build a sort of half-pipe covering a highway you need to consider the pressure induced from the inside by high-speed moving objects and the possibility to resist accidents (preventing an 18 wheeler from completely crash a - say - 100 m section of the half-pipe in case of an accident needs a rather sturdy structure). I mean, aren't these issues already basically solved? I frequently drive through miles-long tunnels under Boston at 70mph.

rtkwe 9y ago
A tunnel is already massively over specced for that because it's preventing the tons of soil/rock/building overhead from collapsing down. The forces for cars passing underneath is minuscule compared to that. For a hypothetical covered roadway you want something much cheaper and lighter so it's not mind numbingly expensive to build.

gorkonsine 9y ago

That's true, I didn't fully elaborate on all that but yeah, there's concerns there that wouldn't exist for a parking lot. However, you bring up a great point with the "snow shed": covering all or part of a road with solar panels like this would also have the side effect of keeping bad weather off the road. How much money would that save in show-shoveling costs, and the costs to society of having roads blocked by snow (and snowplows), and having weather-induced accidents (both rain and snow)? Now, it's probably not feasible to cover every little road in a city with these things, but at least covering major arteries, while probably somewhat expensive due to the engineering challenges you raise, would have some major benefits: keeping the main roads clear even during horrible weather, and also providing a lot of energy from the solar panels.

jaclaz 9y ago
You have an excellent point there, but the costs are unfortunately way too high to be feasible, not even remotely. And you have to consider how - in places where there is snow - you have to choose to either forfeit the (possibly little) energy the panels can produce in winter or anyway clean them from the snow anyway. The good ol' rule of the thumb is that (of course it depends on the country) the cost is 10,000,000 Euro's per km of highway (plain, mainly earthworks), 20,000,000 per km on bridges/viaducts, 30,000,000 per km in tunnels. (the "base" price may of course vary, but the relative proportions remain roughly valid) An artifical tunnel or sbow shed, besides the solar panels, would be probably 1.5 to 1.7 times the cost of the "simple" highway.