To limit the probability of inadequate support for ties, which could lead to the excessive flexing of ties under lateral loads, which could lead to inadequate load distribution among the wythes of multiple-wythe masonry walls, which could lead to an inability to resist transverse or vertical loads, which could lead to cracking or buckling.
This is to limit the probability of:
For floors and elements supporting floors, this is to limit the probability of excessive movement, deflection or vibration, which could lead to negative effects on the psychological well-being of persons.