How do Apartment/Residential Building Repairs/Foundation Floors Or Hallways structure Get repaired or Renovated, when people Still live in the Buildings? (Like the deep structural elements it’s built with like steel, iron, frames, reinforced concrete)

How do Apartment/Residential Building Repairs/Foundation Floors Get repaired or Renovated, when people Still live in the Buildings?

• Lets say in an apartment that has 8-10+ floors. (IMG 1 for example,) The 4th floor, the FLOOR it’s self that the apartments are in, like the hallway, under it, lets say the material used to build it, like the steel, the frame, or whatever material holding it up. the structure or bricks, or whatever material is used to build it, not just the floor or carpet. is getting decayed and or need to get repaired. Maybe even affecting some apartment floors. area you walk on before need to get repaired. What happens? What is usually done if they don’t want to tear down the whole apartment?