Why are lines etched within sidewalks when they're made? I always figure that lines were put contained by the sidewalk to...
I always figure that lines were put contained by the sidewalk to give the sidewalk a shaky spot to crack when the ground shifted, to make it easier to replace a slot if need be, ,and for looks. The piece that confuses me is that sidewalks crack all over the place anyway! Especially where on earth there's a meter box installed.
Answers: The "lines" are crack control joints; or control joint for short. Ideally, since concrete does crack these are an attempt to control where the concrete will crack a bit than have variable cracks. You're right though, sometimes it just cracks. Concrete is tricky within that temperature, slump, etc. adjectives play a role in the final crack resistance.
Sidewalks are created within blocks, the lines simply represents where one block ends and the contemporary one begins... It does engender it easier for individual repair.