“(See Niven’s “Ringworld”)”
IIRC, Niven later wrote about how the Ringworld would be unworkably unstable.
Actually, MIT students had to point that out.
Niven corrected this by adding ramscoop drives along the walls in “Ringworld Engineers”.
But he then provided the solution.
Hence "Scrith"
He's said that the tidal forces on the Ringworld would exceed any known substance's ability to resist and hence he invented Scrith and made the walls and floor from that.
I don't recall where I read it, but I've read most of everything that Niven has written but he did an extensive workup of the Ringworld, doing all the math and such. With known substances, it would develop a death wobble almost immediately and fly apart. This of course assumes that you could mine the materials from nearby bodies, manufacture it in space, and move all the bits around. The ringworld would have mass roughly equal to Jupiter and affect every other celestial body in the system. Station keeping alone would require supercomputers continuously fine tuning the orbit. It's a big project :)