Part of the world not spawning and player falls through it

[GTA 5 GTA 4]

Hi guys , I have a freaking problem with my game ,
literally .. a part of the world doesn't spawn .. and when I go forward to it , I fall ! Just like in this video (

)
NOTE : (I'M NOT THE OWNER OF THE VIDEO)

And I guess it's because some game file are corrupted , but I don't actually know , any help ??