Obtainable Ringworld around the Earth?

Perhaps it would be possible to build a structure which encircles a
planet (such as Earth), but only rotates at orbital speed. This would
make the structure essentially weightless. GEO is probably a good
orbit. The structure could be made very robust. It would not, of
course, be able to support its own weight if spun up to one G, but
then it doesn't have to.

The inside would be, basically, a huge tunnel, perhaps one hundred
kilometers wide and one kilometre high. It wouldn't contain any
atmosphere, and would not be airtight. The inside would be coated
with aluminum.

And maglev vehicles, themselves airtight, would zip around inside the
ring. These vehicles would be one hundred kilometres wide, one
kilometre high, and 264,924 kilometres long, basically filling the
tunnel. This vehicle does rotate fast enough to provide one G, and
cannot support its own weight while doing so. But then it doesn't
have too. The tunnel structure itself does that. As robust as this
structure is, it is also thick enough to serve as a
radiation/micrometeoroid shield.

26,492,400 km of living space, as compared to 148,939,100 km land
area of the Earth itself. So around a fifth of Earth. Not bad.

Would this work, and without unobtainium?