The use for a U bolt that comes to mind when I think of them is as a way of for-sure strapping large amounts of running cords to the walls or ceiling. That's what I use them for in my garage (which has been turned into my woodworking shop, and the power tools require a lot of cords and extension cords.)
I've always wondered what U bolts were actually originally intended for, with that distinct shape and design. I had no idea that they were this versatile -- I've just been using them to hold cords when I could have been using them to reinforce concrete! I feel the sudden need to put the ones I use to a higher purpose.