To limit the probability of insufficient horizontal reinforcement or that the horizontal reinforcement will not be adequately encased and bonded to the concrete, which could lead to the cracking of foundation walls due to temperature changes and shrinkage.
This is to limit the probability of:
For floors and elements supporting floors, this is to limit the probability of excessive deflection, which could lead to rough or uneven walking surfaces, which could lead to persons tripping or falling, which could lead to harm to persons.