I usually find the box of my truck is hard to cover with tarps over winter without them sagging from the weight of snow and nice and filling with water.  So this summer I took the time to design a better way. (I can make it better - some great man said that).  So attached are photos of what I think is an easy fix.

My wife threw out some old drapes anmd I decided to use the aluminum parts for 3 cross members - light but strong.  I cut them to length and covered the ends with thick socks so there would be no sharpm edges.  Then a took 4 steel rods from an old clothes line and spaced them across the aluminum.  The I took some old lattice work that had been laying around and laid a few scrap sheets over the 4 rods.  I think this should provide the shape and strength to deter any build up of ice and snow.  Fingers crossed.