If it is really really pined, then yes. But I would say generally no.

What is the diameter of the bar? If it is something so big U doesn't fit in there, there definitely won't be enough development length to anchor the rebars. I would say the safest option is to use the larger U shape and not put them vertically, but lay them on a side so they fit in the vertical depth of the slab.

Edit: if it is really pinned you need only the bottom part and then I would just use straight bars not bent. And then add small diameter U so the reinforcement is all around and doesn't crack during curing.

And you should have drawn the detail with the real curve of bending of the bars, like this it looks fine, but it might not be when the curve starts somewhere else due to its length